MSC.Nastran 2005 r2 Release Guide Addendum

MSC.Nastran 2005 r2

Release Guide Addendum

CorporateMSC.Software Corporation2 MacArthur PlaceSanta Ana, CA 92707 USATelephone: (800) 345-2078Fax: (714) 784-4056

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Worldwide Webwww.mscsoftware.com

DisclaimerMSC.Software Corporation reserves the right to make changes in specifications and other information contained in this document without prior notice.

The concepts, methods, and examples presented in this text are for illustrative and educational purposes only, and are not intended to be exhaustive or to apply to any particular engineering problem or design. MSC.Software Corporation assumes no liability or responsibility to any person or company for direct or indirect damages resulting from the use of any information contained herein.

User Documentation: Copyright 2006 MSC.Software Corporation. Printed in U.S.A. All Rights Reserved.

This notice shall be marked on any reproduction of this documentation, in whole or in part. Any reproduction or distribution of this document, in whole or in part, without the prior written consent of MSC.Software Corporation is prohibited.

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NA*V2005r2*Z*Z*Z*DC-ADD

C O N T E N T SMSC.Nastran 2005 r2 Release Guide Addendum

MSC.Nastran 2005 r2 Release Guide Addendum

Table of Contents

Table of ContentsPreface ■ List of MSC.Nastran Books, vi

■ Technical Support, vii

■ Internet Resources, ix

1Thermal Contact ■ Release Guide Introduction, 2

■ Thermal Contact Analysis in MSC.Nastran, 3❑ Introduction, 3❑ Input , 3❑ Executive Control Statements, 5❑ Case Control Commands, 5❑ Bulk Data Entries, 5❑ Recommendations, 26❑ Limitations, 27❑ Example Problems, 28

2Thermal Analysis ■ Spatial Dependent Heat Transfer Coefficient, 30

❑ Introduction, 30❑ Input, 30❑ Example, 33

■ Two-Variable Heat Transfer Coefficient Tabular Function, 39❑ Introduction, 39❑ Input, 39❑ Basic Theory and Methods, 44❑ Example – Free Convection of a Horizontal Cylinder

(fconv_axi_2dtable.dat), 45

■ Flux Output Modification for Thermal Analysis, 47❑ Introduction, 47❑ Input, 47❑ Output, 48❑ Basic Theory and Methods, 48❑ Example – Free Convection of a Cube (fconv_cube.dat), 50

❑ Guidelines, 52

INDEX MSC.Nastran Release Guide , 55

MSC.Nastran 2005 r2 Release Guide

Preface

■ List of MSC.Nastran Books

■ Technical Support

■ Internet Resources

vi

List of MSC.Nastran Books

Below is a list of some of the MSC.Nastran documents. You may order any of these documents from the MSC.Software BooksMart site at www.engineering-e.com.

Installation and Release Guides

❏ Installation and Operations Guide

❏ Release Guide

Reference Books

❏ Quick Reference Guide

❏ DMAP Programmer’s Guide

❏ Reference Manual

User’s Guides

❏ Getting Started

❏ Linear Static Analysis

❏ Basic Dynamic Analysis

❏ Advanced Dynamic Analysis

❏ Design Sensitivity and Optimization

❏ Thermal Analysis

❏ Numerical Methods

❏ Aeroelastic Analysis

❏ Superelement

❏ User Modifiable

❏ Toolkit

❏ Implicit Nonlinear (SOL 600)

viiPreface

Technical SupportFor help with installing or using an MSC.Software product, contact your local technical support services. Our technical support provides the following services:

• Resolution of installation problems• Advice on specific analysis capabilities• Advice on modeling techniques• Resolution of specific analysis problems (e.g., fatal messages)• Verification of code error.

If you have concerns about an analysis, we suggest that you contact us at an early stage.

You can reach technical support services on the web, by telephone, or e-mail:

Web Go to the MSC.Software website at www.mscsoftware.com, and click on Support. Here, you can find a wide variety of support resources including application examples, technical application notes, available training courses, and documentation updates at the MSC.Software Training, Technical Support, and Documentation web page.

Phone and Fax

Email Send a detailed description of the problem to the email address below that corresponds to the product you are using. You should receive an acknowledgement that your message was received, followed by an email from one of our Technical Support Engineers.

United StatesTelephone: (800) 732-7284Fax: (714) 784-4343

Frimley, CamberleySurrey, United KingdomTelephone: (44) (1276) 67 10 00Fax: (44) (1276) 69 11 11

Munich, GermanyTelephone: (49) (89) 43 19 87 0Fax: (49) (89) 43 61 71 6

Tokyo, JapanTelephone: (81) (03) 6911 1200Fax: (81) (03) 6911 1201

Rome, ItalyTelephone: (390) (6) 5 91 64 50Fax: (390) (6) 5 91 25 05

Paris, FranceTelephone: (33) (1) 69 36 69 36Fax: (33) (1) 69 36 45 17

Moscow, RussiaTelephone: (7) (095) 236 6177Fax: (7) (095) 236 9762

Gouda, The NetherlandsTelephone: (31) (18) 2543700Fax: (31) (18) 2543707

Madrid, SpainTelephone: (34) (91) 5560919Fax: (34) (91) 5567280

viii

TrainingThe MSC Institute of Technology is the world's largest global supplier of CAD/CAM/CAE/PDM training products and services for the product design, analysis and manufacturing market. We offer over 100 courses through a global network of education centers. The Institute is uniquely positioned to optimize your investment in design and simulation software tools.

Our industry experienced expert staff is available to customize our course offerings to meet your unique training requirements. For the most effective training, The Institute also offers many of our courses at our customer's facilities.

The MSC Institute of Technology is located at:

2 MacArthur PlaceSanta Ana, CA 92707Phone: (800) 732-7211 Fax: (714) 784-4028

The Institute maintains state-of-the-art classroom facilities and individual computer graphics laboratories at training centers throughout the world. All of our courses emphasize hands-on computer laboratory work to facility skills development.

We specialize in customized training based on our evaluation of your design and simulation processes, which yields courses that are geared to your business.

In addition to traditional instructor-led classes, we also offer video and DVD courses, interactive multimedia training, web-based training, and a specialized instructor's program.

Course Information and Registration. For detailed course descriptions, schedule information, and registration call the Training Specialist at (800) 732-7211 or visit www.mscsoftware.com.

MSC.Patran SupportMSC.Nastran SupportMSC.Nastran for Windows SupportMSC.visualNastran Desktop 2D SupportMSC.visualNastran Desktop 4D SupportMSC.Dytran SupportMSC.Fatigue SupportMSC.Interactive Physics SupportMSC.Marc SupportMSC.Mvision SupportMSC.SuperForge SupportMSC Institute Course Information

[email protected]@[email protected]@mscsoftware.comvndesktop.support@mscsoftware.commscdytran.support@[email protected]@[email protected]@mscsoftware.commscsuperforge.support@[email protected]

ixPreface

Internet Resources

MSC.Software (www.mscsoftware.com)

MSC.Software corporate site with information on the latest events, products and services for the CAD/CAE/CAM marketplace.

Simulation Center (simulate.engineering-e.com)

Simulate Online. The Simulation Center provides all your simulation, FEA, and other engineering tools over the Internet.

Engineering-e.com (www.engineering-e.com)

Engineering-e.com is the first virtual marketplace where clients can find engineering expertise, and engineers can find the goods and services they need to do their job

CATIASOURCE (plm.mscsoftware.com)

Your SOURCE for Total Product Lifecycle Management Solutions.

x

MSC.Nastran 2004 r3 Release Guidex

CHAPTER

1 Thermal Contact

■ Release Guide Introduction

■ Thermal Contact Analysis in MSC.Nastran

2

1.1 Release Guide Introduction This addendum to the MSC.Nastran 2005 r2 Release Guide is intended to provide information that was inadvertently left out of the MSC.Nastran 2005 r2 Release Guide. Documentation for Thermal Contact Analysis has been provided and updates have been made to the Spatial Dependent Heat Transfer Coefficient, Two-Variable Heat Transfer Coefficient Tabular Function, and Flux Output Modification for Thermal Analysis sections.

3CHAPTER 1Thermal Contact

1.2 Thermal Contact Analysis in MSC.Nastran

IntroductionThe thermal coupling mechanisms of MSC.Nastran are enhanced by supporting the modeling of thermal contact analysis. There are three possible thermal contact conditions: True touching, Near and Far. Current MSC.Nastran thermal analysis does not address these possibilities but MSC.Nastran SOL 600 does. This project applies thermal contact capabilities using the new MSC.Nastran SOL 600 interface.

SOL 600 is a method by which an MSC.Nastran user can access many of the capabilities of contact without needing to create an additional input file. For thermal contact, the first portion of SOL 600 remains the same. A SOL 600 inputfile is created and executed. SOL 600 assesses the state of thermal contact to determine whether bodies are in true contact, near contact or far away. A special SOL 600 file named the .nthcnt file is generated with this information and other associated data. After SOL 600 execution, a subroutine reads the nthcnt file and creates standard MSC.Nastran heat transfer entities related to the contact status such as CELAS2, CHBDYP, PHBDY, CONV, PCONV, MAT4, etc. The additional MSC.Nastran input data is saved in an include file with the extension .ink. The primary MSC.Nastran job then forms a new MSC.Nastran input file named jid.nast.dat (where jid is the original input name), deletes the BCONTACT Case Control commands (see below), adds a statement for the include file, jid.ink, and spawns off a second MSC.Nastran job from the primary MSC.Nastran run. Results for the secondary MSC.Nastran run are the desired outputs. All possible MSC.Nastran outputs are available and are selected by standard. For example, op2, xdb, punch, f06, etc. are all available.

Input In order to run an MSC.Nastran thermal contact analysis the following items must be input to the original MSC.Nastran input file:

Executive Control statements

• Change SOL 153 to SOL 600,153 for steady state thermal analysis.

• Change SOL 159 to SOL 600,159 for transient thermal analysis.

Case Control commands

• Insert BCONTACT=0 above any SUBCASE statement (if present). If SUBCASE is not present, it can go anywhere in the Case Control.

• Only one subcase is allowed.

4

• For Far Thermal Contact mode, SPC and TEMPERATURE(INITIAL) commands must be defined for steady state thermal analysis; SPC and IC commands must be defined for transient thermal analysis.

Bulk Data entries – Include the following entries:

• BSURF entries as described in the MSC.Nastran Quick Reference Guide.

• BCBODY entries as described below (these have been modified from what is shown in the MSC.Nastran Quick Reference Guide).

• BCTABLE entries as described below (these have been modified from what is shown in the MSC.Nastran Quick Reference Guide).

• An optional TCNTPRM entry as described below (this is a new entry).

An optional File in same directory as your MSC.Nastran input file.

• This file must be named heatm.rc (lower case).

• This file is required only when the parameter MARHEATM=1 (see below).

• This file is used as the rc file to control the second MSC.Nastran job.

• As a minimum this file should contain the following lines:

Batch=no

Memory=xxxx (required memory for your job unless it is a small job.)

• Additional lines that are frequently used:

scr=yes

out=jid (where jid is the name of the original MSC.Nastran job.) Note: if out=jid is not included, a set of files named jid.nast.dat, jid.nast.f06, jid.nast.f04, jid.nast.log, jid.nast.op2, etc. contains the final results. If out=jid is included, then jid.nast.dat, jid.f06, jid.f04, jid.log, jid.op2, etc. contain the final results and jid.f06.1, jid.f04.1, jid.log.1 contain the information for the primary MSC.Nastran execution. For both cases jid.marc.dat, jid.marc.out, jid.marc.sts, jid.marc.log, jid.marc.nthcnt and jid.marc.t16 contain the SOL 600 information.

• These jobs should not be run using outdir defined.

• These jobs should be run on the same machine where MSC.Nastran resides.

• These jobs must use a single processor for both MSC.Nastran and SOL 600.


Executive Control StatementsSpecify SOL 600,153 for steady state thermal analysis and SOL 600,159 for transient thermal analysis.

Case Control Commands

BCONTACT

For thermal contact the only allowed option is

BCONTACT=0

All other forms of this entry are not valid for thermal contact. BCONTACT=0 means that a SOL 600 Contact Table will be input to SOL 600’s “Model Definition” section rather than in the history definition. This is required because the initial contact status is the only item examined.

IC

This command must be specified for the transient models with far thermal contact mode.

SPC

This command must be specified for far thermal contact mode.

TEMPERATURE(INITIAL)

This command must be specified for the steady state models with far thermal contact mode.

Bulk Data Entries

Please consult the MSC.Nastran Quick Reference Guide for BSURF entries. These are the same for thermal contact as for structural contact.

BSURF Defines a Contact Surface

BCTABLE Defines a contact table

6

Format:

1 2 3 4 5 6 7 8 9 10

BCTABLE ID NGROUP

“SLAVE” IDSLA1 ERROR FNTOL FRIC CINTERF IGLUE

ISEARCH ICOORD JGLUE TOLID DQNEAR DISTID

FRLIM BIAS SLIDE HARDS

HTC HCV HNC BNC EMISS HBL

“MASTERS” IDMA1 IDMA2 IDMA3 IDMA4 IDMA5 IDMA6 IDMA7

IDMA8 IDMA9 ...

Field Contents

ID ID corresponding to a Case Control BCONTACT entry for the subcase to which this data applies. See Remark 6. (Integer, required)

NGROUP(2,1) [2,1]

Flag to indicate if the continuation entries “SLAVE” and “MASTERS are entered or not. Zero means no continuation entries are entered. Any positive integer means one or more sets of slave/master entries are entered. (Integer; Default = 1)

“SLAVE” Indicates that this line defines the touching body and its parameters.

IDSLA1 (4,1) [3,1]

Identification number of a BCBODY Bulk Data entry defining the touching body. (Integer > 0)

ERROR(3,2) [3,2]

Distance below which a node is considered touching a body. Default = blank, automatic calculation) (Real)

FNTOL(3,5) [5,1]

Separation force above which a node separates from a body. Default = maximum residual force) (Real).

FRIC(3,4) [5,2]

Friction coefficient (Real > 0.0; Default =0.0)

CINTERF(3,6) [5,3]

Interference closure amount, normal to the contact surface. Default = 0.0)CINTERF > 0.0 overlap between bodies; CINTERF < 0.0 gap between bodies. (Real)


IGLUE(3,7) [3,7]

Flag to activate glue option. (Integer > 0; Default = 0, no glue option)

1. Activates the glue option. In the glue option, all degrees of freedom of the contact nodes are tied in case of deformable-deformable contact once the node comes in contact. The relative tangential motion of a contact node is zero in case of deformable-rigid contact.

2. Activates a special glue option to insure that there is no relative tangential and normal displacement when a node comes into contact. An existing initial gap or overlap between the node and the contacted body will not be removed, as the node will not be projected onto the contacted body.

ISEARCH(3,8) [3.8]

Enter a value of 1 to indicate that the searching order for deformable contact bodies is from the touching body to the touched bodies. Enter 2 to let the program decide which searching order is optimal for deformable bodies. (Integer; Default = 2)

ICOORD(3,9), [3,9]

Enter 1 to modify the coordinates of a node in contact with a deformable body so that stress-free initial contact can be obtained. Enter 2 to extend the tangential error tolerance at sharp corners of deformable bodies to delay sliding off a contacted segment. Enter 3 to have both 1 and 2 active. (Integer; Default 0)

JGLUE(3,10) [3,10]

This option is only relevant if the glue option is invoked (IGLUE > 0). Enter 0 if a node should not separate. Enter 1 to invoke the standard separation behavior based on the maximum residual force. (Integer; Default = 0)

TOLID(4,2) [4,2]

Contact tolerance table ID. Used in heat transfer analysis only. (Integer; Default = 0, which means no table ID)

DQNEAR (3,3) [3,3]

Distance below which near thermal contact behavior occurs. Used in heat transfer analysis only. Default = 0 which means near contact does not occur) (Real)

DISTID(4,3) [4,3]

Contact near distance table ID. Used in heat transfer analysis only. (Integer; Default = 0 which means no table ID)

8

FRLIM[5,4]

Friction stress limit. This entry is only used for friction type 6 (Coulomb friction using the bilinear model). If the shear stress due to friction reaches this limit value, then the applied friction force will be reduced so that the maximum friction stress is given by, with the friction coefficient and the contact normal stress. (Real, Default = 1.0E20)

BIAS[5,5]

Contact tolerance bias (value between 0.0 and 1.0). A non-blank entry will override the BIAS entered on the BCBODY entry. (Real, no default)

SLIDE[5,6]

Delayed slide off distance (Real, Default – see next few sentences). This entry should not be made unless ICOORD=2 (see above). When using the delayed slide off option, a node sliding on a segment will slide off this segment only if it passes the node (2-D) or edge (3-D) at a sharp corner over a distance larger than the delayed slide off distance. By default, the delayed slide off distance is related to the dimensions of the contacted segment by a 20 percent increase of its isoparametric domain.

HARDS[5,7]

Hard-soft ratio. This entry is only used if double-sided contact with automatic constraint optimization is used, as defined on the BCBODY entry. The hard-soft ratio can be used by the program if there is a significant difference in the (average) stiffness of the contact bodies (expressed by the trace of the initial stress-strain law). If the ratio of the stiffness is larger than the hard-soft ratio, the nodes of the softest body are the preferred slave nodes. (Real, Default = 2.0)

HTC[7,1] /[8,1]

Contact heat transfer coefficient. If real, the value entered is the contact heat transfer coefficient. If integer, the value entered is the ID of a TABLEM1 entry specifying the contact heat transfer coefficient vs. temperature. (Real or Integer; Default = 0.0 for a heat transfer problem, omit for a structural problem)

HCV[7,2)]/[8,2]

Convection coefficient for near field behavior. If real, the value entered is the near field convection coefficient. If integer, the value entered is the ID of a TABLEM1 entry specifying the near field convection coefficient vs. temperature. (Real or Integer; Default = 0.0 for a heat transfer problem, omit for a structural problem)


Remarks:

1. BCTABLE defines surface contact. Line contact is not available. At present beam-beam, beam-shell and beam-solid contact is not available.

2. BCTABLE is required for thermal contact.

3. Fields 3 and 4 of the first line are not available for thermal contact.

4. NGROUP is required. For thermal contact NGROUP must be zero.

5. For MSC.Nastran thermal contact analysis, parameters SIGMA and TABS must be specified if EMISS is not zero.

6. The maximum number of touching bodies is 99.

HNC[7,3] /[8,3]

Natural convection coefficient for near field behavior. If real, the value entered is the near field natural convection coefficient. If integer, the value entered is the ID of a TABLEM1 entry specifying the near field natural convection coefficient vs. temperature. (Real or Integer; Default = 0.0 for a heat transfer problem, omit for a structural problem)

BNC[7,4] /[8,4]

Exponent associated with the natural convection coefficient for near field behavior (Real; Default = 1.0 for a heat transfer problem, omit for a structural problem).

EMISS[7,5]/[8,5]

Emissivity for radiation to the environment or near thermal radiation. If real, the value entered is the emissivity. If integer, the value entered is the ID of a TABLEM1 entry specifying the emissivity vs. temperature. (Real or Integer; Default = 0.0 for a heat transfer problem, omit for a structural problem)

HBL[7,6]/[8,6]

Separation distance dependent thermal convection coefficient. If real, the value entered is the separation distance dependent thermal convection coefficient. If integer, the value entered is the ID of a TABLEM1 entry specifying the separation distance dependent thermal convection coefficient. (Real or Integer; Default = 0.0 for a heat transfer problem, omit for a structural problem)

“MASTERS” Indicates the start of the list of bodies touched by touching body IDSLA1.

IDMAi(4,i) [15,I]

Identification numbers of BCBODY Bulk Data entries defining touched bodies (Integer > 0).

10

7. (i,j) indicates the ith datablock jth field of SOL 600’s CONTACT TABLE (without tables) history definition. [i,j] indicates SOL 600’s Contact Table (with Tables). Heat transfer options require MSC.Nastran and SOL 600 licensing. All heat transfer options pertain to SOL 600 Contact Table with Tables.

Use only as many forms (i.e. HEAT, PATCH3D, BEZIER, POLY, CYLIND, SPHERE, NURBS2, or NURBS) as necessary to describe the body (if rigid). Deformable bodies are described using as many standard elements as necessary and are specified by the BSID field with BEHAV=DEFORM (only the first line should be entered for deformable bodies). The “RIGID” header may be used with any of the other rigid entries but only once per body. See Remark 5 for an important note regarding how to define the outward direction of rigid bodies (which must point towards a flexible body for contact to occur).

The order by which the bodies are defined is important for flexible surfaces. Fine grid surfaces must be defined first and coarse grid surfaces last. Order the bodes from the most fine to most coarse grids

Examples (of Deformable and Rigid Contact):

Example 1 – Typical deformable body

BCBODY Defines a Flexible or Rigid contact Body in 2D or 3D

1 2 3 4 5 6 7 8 9 10

BCBODY BID DIM BEHAV BSID ISTYP FRIC IDSPL CONTROL

NLOAD ANGVEL DCOS1 DCOS2 DCOS3 VELRB1 VELRB2 VELRB3

“RIGID” CGID NENT Rigid Body Name

“HEAT” CFILM TSINK CHEAT TBODY HCV HNC ITYPE

BNC EMISS HBL

BCBODY 1 DEFORM 101 0 .05


Example 2 – Simple 4-node rigid patch (see note 5 for rigid bodies)

BCBODY 2 RIGID 102 0 .08

RIGID 301 302 303 304

Field Contents

BID(4,1)

Contact body identification number referenced by BCTABLE, BCHANGE, or BCMOVE. (Integer > 0, Required)

DIM Dimension of body (Integer, Default = 3).DIM=2 Planar (2D) body in x-y plane of the basic coordinate system, composed of 2D elements or curves. DIM=3 Any 3D body composed of rigid surfaces, shell elements or solid elements.

BEHAV (4,8)

Behavior of curve or surface. DEFORM body is deformable, RIGID body is rigid, SYMM body is a symmetry body, ACOUS indicates an acoustic body, WORK indicates body is a workpiece, HEAT indicates body is a heat-rigid body. (Character, Default = DEFORM)

BSID Identification number of a BSURF, BCBOX, BCPROP or BCMATL entry if BEHAV=DEFORM. (Integer > 0)

ISTYP(4,3)

Check of contact conditions. (Integer > 0; Default = 2 for deformable and 0 for rigid)

For a deformable body=0 symmetric penetration, double sided contact.=1 unsymmetric penetration, single sided contact (Integer>0). =2 Double-sided contact with automatic optimization of contact constraint equations.

For a rigid body=0 no symmetry condition on rigid body.=1 rigid body is a symmetry plane.

FRIC(6,7)

Friction coefficient. (Real > 0; Default = 0)

12

IDSPL (4,5)

Activates the SPLINE (analytic) option for a deformable body (Integer; Default = 0).

=0 or blank, SPLINE option is turned off.= 1, The body is smoothed out with splines (2D) or Coons surfaces. > 1 Identification number of a BLSEG entry that lists nodes on edges of the body which are excluded from the SPLINE option. These nodes are entered in pairs. For a quad surface (for example CQUAD4 or edge of a CHEXA), usually 4 sets of nodal pairs are needed to describe the surface. For example a CQUAD4 with grid numbering 1,2,4,3 would need pairs of nodes 1,2 2,3, 4,3, and 3,1. The nodal pairs may be entered in any order. For related information please see, MSC.Marc Volume C SPLINE option documentation.

CONTROL (4,6)

Indicates the type of control for the body (Integer), = -1 for position control, =0 for velocity control, = positive number for load control (the positive number is the grid number which has displacement degrees of freedom controlling the body). The position of this grid is at the center of rotation given in the CGID field. The velocity/displacement of the body must be specified by the VELRBi fields rather than SPCD.

NLOAD (4,7)

Enter a positive number if load controlled and rotations are allowed (Integer). The positive number is the grid number which has the rotation(s) of the body as degrees of freedom. The position of this grid is at the center of rotation given in the CGID field.

ANGVEL (6,1)

Angular velocity or angular position about local axis through center of rotation. (Real; Default = 0.0)

DCOS1 (6,4)

3D - First component direction cosine of local axis if ANGVEL is nonzero. 2D -- First coordinate of initial position of rotation of rigid body. (Real)

DCOS2 (6,5)

3D -- Second component direction cosine of local axis if ANGVEL is nonzero 2D -- Second coordinate of initial position of rotation of rigid body (Real).

DCOS3 (6,6)

3D -- Third component direction cosine of local axis if ANGVEL is nonzero 2D -- Not used. (Real)

VELRB1 (5,4)

2D & 3D -- Velocity or final position (depending on the value of CONTROL) of rigid body in first direction. (Real)

Field Contents


VELRB2 (5,5)

2D & 3D -- Velocity or final position (depending on the value of CONTROL) of rigid body in second direction. (Real)

VELRB3 (5,6)

3D -- Velocity or final position (depending on the value of CONTROL) of rigid body in third direction. (Real)

2D -- Not used

“RIGID” The entries of this continuation line are for the rigid body description. (See Remark 5.)

CGID(5,i) i=1,2,3(4,6)

Grid point identification number defining the initial position of the center of rotation for the rigid body or the point where a concentrated force or moment is applied.

NENT(4,2)

Number of geometric entities to describe this rigid surface. A rigid surface can be described by multiple sets of patches, nurbs, etc. For example if it takes 3 sets of PATCH3D entries to describe a rigid surface, then set NENT=3. (Integer>0; Default=1)

Rigid Body Name (4,9)

Name associated with the rigid body. (Default is blank, 24-characters maximum.)

“HEAT” The entries of this continuation line(s) are for contact in heat transfer. Do not enter these line(s) for structural analyses.

CFILM(9,1) /(10,1)

Heat transfer coefficient (film) to environment (Real or Integer; Default=0.0 for a heat transfer problem, omit for a structural problem) If real, the value entered is the film coefficient. If integer, the value entered is the ID of a TABLEM1 entry specifying the heat transfer coefficient vs. temperature. This is usually called Hcve in the SOL 600 documentation.

TSINK(9,2) /(10,2)

Environment sink temperature (Real; Default = 0.0 for a heat transfer problem, omit for a structural problem).

CHEAT(9,3) /(10,3)

Contact heat transfer coefficient (Real or Integer; Default = 0.0 for a heat transfer problem, omit for a structural problem). If real, the value entered is the contact heat transfer coefficient. If integer, the value entered is the ID of a TABLEM1 entry specifying the contact heat transfer coefficient vs. temperature.

TBODY(9,4) /(10,4)

Body temperature. (Real: Default = 0.0 for a heat transfer problem, omit for a structural problem).

Field Contents

14

Remarks:

1. Named continuation entries are ignored for a deformable curve or surface (BEHAV=DEFO), except for “HEAT”.

2. The grid CGID is the reference grid for the rigid body motion. Loads and enforced motion must be defined in the global coordinate system of CGID.

3. Continuation lines are required for thermal contact.

4. BCBODY is recognized only in SOL 600 and SOL 700.

HCV(9,5) /(10,5)

Convection coefficient for near field behavior. If real, the value entered is the near field convection coefficient. If integer, the value entered is the ID of a TABLEM1 entry specifying the near field convection coefficient vs. temperature. (Real or Integer; Default = 0.0 for a heat transfer problem, omit for a structural problem)

HNC(9,6) /(10,6)

Natural convection coefficient for near field behavior. If real, the value entered is the near field natural convection coefficient. If integer, the value entered is the ID of a TABLEM1 entry specifying the near field natural convection coefficient vs. temperature. (Real or Integer; Default = 0.0 for a heat transfer problem, omit for a structural problem)

ITYPE[4,8]

An optional entry for heat transfer only (Integer, no default).

1 – Heat sink

4 – Heat conduction body

BNC(9,7) /(10,7)

Exponent associated with the natural convection coefficient for near field behavior. (Real; Default = 1.0 for a heat transfer problem, omit for a structural problem)

EMISS(9,8)/(10,8)

Emissivity for radiation to the environment or near thermal radiation. If real, the value entered is the emissivity. If integer, the value entered is the ID of a TABLEM1 entry specifying the emissivity versus temperature. (Real or integer; Default = 0.0 for a heat transfer problem, omit for a structural problem)

HBL(7,6)/(8,6)

Separation distance dependent thermal convection coefficient. If real, the value entered is a convection coefficient. If integer, the value entered is the ID of a TABLEM1 entry specifying the convection coefficient versus temperature. (Real or Integer; Default = 0.0 for a heat transfer problem, omit for a structural problem)

Field Contents


5. WARNING: For rigid contact, the right hand rule determines the interior side of the rigid surface. A deformable surface which contacts a rigid surface must be on the exterior side of the rigid surface (i.e. in the direction opposite to the right hand rule). If a rigid surface is described backwards, contact will not occur because the deformable body is already inside the rigid body at the start of the analysis. For 3D patches, if all need to be reversed, the parameter PARAM,MARCREVR,1 may be entered to automatically reverse all 3D patches.

6. (i,j) refers to data block i and field j of SOL 600’s CONTACT model definition entry. IDSPL covers the SPLINE history definition in SOL 600. For structural analysis (i,j) refers to contact without tables. For heat transfer (i,j) refers to contact with tables.

7. The heat transfer options are available starting with MSC.Nastran and must use SOL 600 licensing. Heat transfer uses SOL 600’s Contact with Tables.

8. For MSC.Nastran thermal contact analysis, parameters SIGMA and TABS must be specified if EMISS is not zero.

9. For heat transfer items described using a TABLEM1 ID, the smallest value in the table will be entered into SOL 600’s 9th contact (with tables) datablock. The table ID will be translated directly to SOL 600’s 10th contact (with tables) datablock.

Overrides default values of parameters for thermal contact resistance.

Format:

Example:

TCNTPRM Parameters for thermal contact resistance

1 2 3 4 5 6 7 8 9 10TCNTPRM PARAM1 VAL1 PARAM2 VAL2 PARAM3 VAL3 PARAM4 VAL4

PARAM5 VAL5 PARAM6 VAL6 PARAM7 VAL7 PARAM8 VAL8

TCNTPRM OCELAS 1500 OMAT4 200 ORADBC 9000

16

Remarks:

1. The TCNTPRM entry changes the default starting IDs of the elements, properties, or scalar points that are generated internally for thermal contact resistance. None of the parameters of this entry are required. The default settings should be changed when the IDs are conflicting with the existing entries. Only one TCNTPRM entry is allowed in the Bulk Data Section.

2. The numbering starts with the offset value + 1.

Field Contents

PARAMi Name of the thermal contact resistance parameter. Allowable names are listed in Table 1-1. (Character)

VALi Value of the parameter. (Integer, see Table 1-1.)

Table 1-1 PARAMi Names and Descriptions

Name Type Default Description

OCELAS Integer > 0 700000 Offset for identification numbers of generated CELAS2 elements.

OCHBDY Integer > 0 800000 Offset for identification numbers of generated CHBDYP elements.

OPHBDY Integer > 0 810000 Offset for identification numbers of generated PHBDY element property entries.

OPCONV Integer > 0 820000 Offset for identification numbers of generated PCONV element property entries.

OMAT4 Integer > 0 830000 Offset for identification numbers of generated MAT4 and MATT4 material property entries.

ORADM Integer > 0 840000 Offset for identification numbers of generated RADM and RADMT radiation material property entries.

OSPOINT Integer > 0 900000 Offset for identification numbers of generated scalar points.


Parameter

PARAM,MARHEATM

Determines whether a file named heatm.rc is necessary to run the second phase of SOL 600 heat transfer initial contact jobs (Integer; Default = 0).

Basic Theory and Methods

MSC.Nastran thermal contact analysis applies the algorithms that have been implemented in SOL 600 to determine the following contact data.

1. The nodes that are in contact with the edges or faces of other elements.

2. Contact mode (true thermal contact, near thermal contact, or far thermal contact).

3. The natural coordinate ( ) of the node with respect to the contact edge (2-D), or the natural coordinates ( ) of the node with respect to the contact face (3-D).

4. The effective area ( ).

The above information will be used to calculate the effective thermal conductivity elements or the equivalent convection or radiation elements.

True Thermal Contact

For true thermal contact, the effective heat flow between a node on the contacting body and a node on the contacted body can be expressed as follows.

0 heatm.rc is not required. Defaults will be used. The defaults are scr=yes batch=no mem=80mw

1 A heatm.rc file will be supplied by the user in the same directory as the MSC.Nastran input file. The heatm.rc file can contain any information used by other rc files except that batch=no. If the original MSC.Nastran input file is name jid.dat (or jid.bdf) and out=jid is specified, the final output will be in such as jid.f06, jid.op2, and jid.xdb. If out=jid is not specified, the final output will be in files such as jid.nast.f06, jid.nast.op2, and jid.nast.xdb.

ξξ η,

AreaAA'

AA'

QAA' hCT TA TA'–( ) AreaAA'⋅=

18

where:

For Line Contact Analysis:

where is the natural coordinate of with respect to line segment CD.

Substitute by and in the heat flow equation:

= a point on the contacted body that node contacts.

= the contact heat transfer coefficient.

= the temperature at node .


= the effective contact area associated with node .

A' A

hCT

TA A

TA' A'

AreaAA' A

AreaAA' AB thickness 2⁄⋅=

TA' 1 ξA'–( )TC 2⁄ 1 ξA'+( )TD 2⁄+=

ξA' A'

TA' TC TD

QAA' hCT AreaAA' 1 ξA'–( )⋅ TA TC–( ) 2⁄ +⋅=

hCT AreaAA' 1 ξA'+( ) TA TD–( ) 2⁄⋅ ⋅


The effective stiffness values between A and C and between A and D are listed below.

For Face Contact Analysis:

This is equivalent to four pairs of thermal conductivity elements with the following stiffness.

KAC hCT AreaAA' 1 ξA'–( ) 2⁄⋅ ⋅=

KAD hCT AreaAA' 1 ξA'+( ) 2⁄⋅ ⋅=

AreaAA' AreaABCD 4⁄=

TA' 1 ξA'–( ) 1 ηA'–( )TE 4⁄ 1 ξA'+( ) 1 ηA'–( )TF 4⁄ 1 ξA'+( ) 1 ηA'+( )TM 4⁄ 1 ξA'–( ) 1 ηA'+( )TL 4⁄+ + +=

QAA' hCT AreaAA' 1 ξA'–( ) 1 ηA'–( ) TA TE–( ) 4⁄ hCT AreaAA' 1 ξA'+( ) 1 ηA'–( ) TA TF–( ) 4⁄ +⋅ ⋅+⋅ ⋅=

hCT AreaAA' 1 ξA'+( ) 1 ηA'+( ) TA TM–( ) 4⁄ hCT AreaAA' 1 ξA'–( ) 1 ηA'+( ) TA TL–( ) 4⁄⋅ ⋅+⋅ ⋅

AE hCT AreaAA' 1 ξA'–( ) 1 ηA'–( ) 4⁄⋅ ⋅=

AF hCT AreaAA' 1 ξA'+( ) 1 ηA'–( ) 4⁄⋅ ⋅=

AM hCT AreaAA' 1 ξA'+( ) 1 ηA'+( ) 4⁄⋅ ⋅=

AL hCT AreaAA' 1 ξA'–( ) 1 ηA'+( ) 4⁄⋅ ⋅=

20

If is constant, MSC.Nastran will generate CELAS2 elements with K equal to the effective stiffness.

For Line Contact:CELAS2, EID, , GA, 1, GC, 1CELAS2, EID, , GA, 1, GD, 1

For Face Contact:CELAS2, EID, , GA, 1, GE, 1CELAS2, EID, , GA, 1, GF, 1CELAS2, EID, , GA, 1, GM, 1CELAS2, EID, , GA, 1, GL, 1

If is temperature dependent, MSC.Nastran will generate a set of CHBDYP, PHBDY, CONV, PCONV, MAT4, and MATT4 entries.

For Line Contact:CHBDYP, EID1, PID1, POINT, , , GAPHBDY , PID1,

CONV , EID1, PID, , , GCCHBDYP, EID2, PID2, POINT, , , GAPHBDY , PID2,

CONV , EID2, PID, , , GDPCONV , PID, MIDMAT4 , MID, , , , hctMATT4 , MID, , , , T(H)

For Face Contact:CHBDYP, EID1, PID1, POINT, , , GAPHBDY , PID1,

CONV , EID1, PID, , , GECHBDYP, EID2, PID2, POINT, , , GAPHBDY , PID2, CONV , EID2, PID, , , GFCHBDYP, EID3, PID3, POINT, , , GAPHBDY , PID3, CONV , EID3, PID, , , GMCHBDYP, EID4, PID4, POINT, , , GAPHBDY , PID4, CONV , EID4, PID, , , GLPCONV , PID, MIDMAT4 , MID, , , , hctMATT4 , MID, , , , T(H)

Note that the T(H) ID specified in the MATT4 entry is same as the T(H) ID specified in the original BCTABLE or BCBODY contact entry.

hCT

KACKAD

KAEKAFKAMKAL

hCT

AreaAA ′ 1 ξA'–( ) 2⁄⋅

AreaAA ′ 1 ξA'–( ) 2⁄⋅

AreaAA ′ 1 ξA'–( ) 1 ηA'–( ) ⁄⋅

Area AA ′ 1 ξA'+( ) 1 ηA'–( ) ⁄⋅

Area AA ′ 1 ξA'+( ) 1 ηA'+( ) ⁄⋅

Area AA ′ 1 ξA'–( ) 1 ηA'+( ) ⁄⋅


Near Thermal Contact

For near thermal contact, the geometry computation is same as the previous case; however, the heat transfer includes both convection and radiation boundary conditions. The heat flux equation is more complicated, as listed below.

where:

In this case, the convection terms , , and can be processed in a same way as the true contact mode. The natural convection term can also be processed in a similar way except that the contents of PCONV entry are replaced by the following.

PCONV , PID, MID, BNC-1

For the radiation term, MSC.Nastran will generate a set of CHBDYP, PHBDY, RADBC, RADM, and RADMT entries. The RADMT entry is required only when the emissivity is temperature dependent.

For Line Contact:CHBDYP, EID1, PID1, POINT, , , GAPHBDY , PID1,

= a point on the contacted body that node contacts.

= the convection coefficient for near field behavior.



= the natural convection coefficient for near field behavior.

= the exponent associated with natural convection.

= the Stefan Boltzman constant.

= the effective emissivity of the surface.

= the contact heat transfer coefficient.

= the separation distance dependent heat transfer coefficient.

= the distance between the two surfaces.

= the near contact distance.

qAA' hCV TA TA'–( ) hNC TA TA'–( )BNC σε TA4

TA'4

–( ) + ++=

hCT 1. S DNEAR⁄–( ) hBLS DNEAR⁄+{ } TA TA'–( )

A' A

hCV

TA A

TA' A'

hNC

BNC

σ

ε

hCT

hBL

S

DNEAR

hCV hCT hBL

hNC

Area AA ′ 1 ξA'–( ) ⁄⋅

22

RADBC , GC, 1.0, , EID1CHBDYP, EID2, PID2, POINT, , , GAPHBDY , PID2, Area RADBC , GD, 1.0, , EID2RADM , MID, , RADMT , MID, T( ), T( )

For Face Contact:CHBDYP, EID1, PID1, POINT, , , GAPHBDY , PID1, Area RADBC , GE, 1.0, , EID1CHBDYP, EID2, PID2, POINT, , , GAPHBDY , PID2, Area RADBC , GF, 1.0, , EID2CHBDYP, EID3, PID3, POINT, , , GAPHBDY , PID3, Area RADBC , GM, 1.0, , EID3CHBDYP, EID4, PID4, POINT, , , GAPHBDY , PID4, Area RADBC , GL, 1.0, , EID4RADM , MID, ,RADMT , MID, T( ), T( )

Far Thermal Contact

If neither true thermal contact nor near thermal contact exists, the surface will have a convection and radiation heat transfer to the environment. Therefore, the heat flux is defined as follows.

where:

Note: CHBDYP and PHBDY entries are same as those defined for convection boundary conditions. As a result, only one pair of CHBDYP and PHBDY is required for each entity.

The ID specified in the RADMT entry is same as the ID specified in the original BCTABLE or BCBODY contact entry.

= the heat transfer coefficient to the environment.


= the environmental temperature.

= the Stefan Boltzman constant.

= the effective emissivity of the surface.

AA' 1 ξA'+( ) 2⁄⋅

ε εε ε

AA' 1 ξA'–( ) 1 ηA'–( ) 4⁄⋅

AA' 1 ξA'+( ) 1 ηA'–( ) 4⁄⋅

AA' 1 ξA'+( ) 1 ηA'–( ) 4⁄⋅

AA' 1 ξA'–( ) 1 ηA'+( ) 4⁄⋅

ε εε ε

AA'

T ε( ) T ε( )

qA hCVE TA TENV–( ) σε TA4

TENV4

–( )+=

hCVE

TA A

TENV

σ

ε


For the convection term, MSC.Nastran will generate a set of CHBDYP, PHBDY, CONV, PCONV, SPOINT, SPC, MAT4, and MATT4 entries. The MATT4 entry is required only when is temperature dependent.

CHBDYP, EID, PID, POINT, , , GA, , ,PHBDY , PID, Area CONV , EID, PID, , , S1PCONV , PID, MIDSPOINT, S1SPC , SID, S1, 1, MAT4 , MID, , , , MATT4 , MID, , , , T(H)

Note that the T(H) ID specified in the MATT4 entry is same as the T(H) ID specified in the original BCBODY contact entry.

For the radiation term, MSC.Nastran will generate a set of CHBDYP, PHBDY, RADBC, SPOINT, SPC, RADM, and RADMT entries. The RADMT entry is required only when the emissivity is temperature dependent.

CHBDYP, EID, PID, POINT, , , GA, , , , MIDPHBDY , PID, Area RADBC , S1, 1.0, , EIDSPOINT, S1SPC , SID, S1, 1, TENVRADM , MID, ,RADMT , MID, T( ), T( )

The contact regions should be carefully designed to avoid Far Thermal Contact mode because it is more efficient to model the free convection and radiation boundary conditions directly using the generic CONV and RADBC elements in MSC.Nastran.

Example – Thermal contact of two plates with dissimilar meshes (tcnttr2d.dat)

This example demonstrates the thermal contact analysis between two horizontal plates. In this problem, the contact heat transfer coefficient between these two plates is 500.0 W/ . A heat flux of 1000 W/ is imposed on the upper plate with 7x7 mesh. The lower plate with 10x10 mesh has a free convection heat transfer ( h = 1000.0 W/ to an ambient environment with temperature .

The MSC.Nastran input file is listed below.

Note: CHBDYP, PHBDY, SPOINT, and SPC entries are same as those defined for convection term. As a result, only one set of CHBDYP, PHBDY, SPOINT, and SPC is required for each entity

The T( ) ID specified in the RADMT entry is same as the T( ) ID specified in the original BCBODY contact entry.

hCVE

AA'

TENVhCVE

AA'

ε εε ε

AA'

ε ε

m2 Co⋅ m2

m2 Co⋅ 0.0 Co

24

SOL 600,153CENDANALYSIS = HEATECHO = NONETEMPERATURE(INITIAL) = 2bcontact=0SUBCASE 1$ Subcase name : casea SUBTITLE=casea NLPARM = 1 SPC = 1 LOAD = 3 THERMAL(SORT1,PRINT)=ALLBEGIN BULKPARAM POST 0PARAM AUTOSPC YESPARAM SIGMA 1.714-9NLPARM 1 0 AUTO 5 25 PW NO .001 1.-7$ Elements and Element Properties for region : pshell.1PSHELL 1 1 .01$ Pset: "pshell.1" will be imported as: "pshell.1"CQUAD4 26 1 55 56 64 63 0.CQUAD4 27 1 56 57 65 64 0.:CQUAD4 74 1 109 110 118 117 0.CQUAD4 75 1 119 120 131 130 0.CQUAD4 76 1 120 121 132 131 0.CQUAD4 77 1 121 122 133 132 0.:CQUAD4 173 1 226 227 238 237 0.CQUAD4 174 1 227 228 239 238 0.$ Referenced Material Records$ Material Record : mat4.1$ Description of Material :MAT4 1 150. $ Nodes of the Entire ModelGRID 55 11. 11. 11.GRID 56 11. 10.8571 11.:GRID 117 10. 10.1429 11.GRID 118 10. 10. 11.GRID 119 11. 10. 10.GRID 120 10.9 10. 10.:GRID 238 10.1 11. 10.GRID 239 10. 11. 10.$ Loads for Load Case : casea$ Fixed Temperatures of Load Set : conv.1.1SPC 1 240 1 0.$ Normal Heat Flux of Load Set : qhbdy.1QBDY3 3 1000.0 100001:QBDY3 3 1000.0 100049$ Convection to Ambient of Load Set : conv.1.1PCONV 1 1001 0 0.CONV 100050 1 0 0 240:CONV 100149 1 0 0 240


$ Contact body one = cquad4 eid 75 - 174$ Contact body two = cquad4 eid 26 - 74$ True contact mode hcv = 500.bsurf, 101, 75, thru, 174bsurf, 102, 26, thru, 74bcbody, 111, , heat, 101,, heat, 0., 0., 0., 0., 0., 0., 4, , 0., 0., 0.bcbody, 112, , heat, 102,, heat, 0., 0., 0., 0., 0., 0., 4, , 0., 0., 0.bctable, 0, , , 1, slave, 111, 1.5, , , , , , 2.0, , , 500., 0., 0., 0., 0., master, 112$ Initial Temperatures from Temperature Load SetsTEMP 2 240 0.$ Default Initial TemperatureTEMPD 2 0.$ CHBDYG Surface ElementsCHBDYG 100001 AREA4 55 56 64 63:CHBDYG 100049 AREA4 109 110 118 117CHBDYG 100050 AREA4 119 120 131 130:CHBDYG 100149 AREA4 227 228 239 238$ Free Convection Heat Transfer CoefficientsMAT4 1001 1000.$ Scalar PointsSPOINT 240ENDDATA

The analysis results are shown below.

26

Recommendations• To get better results, it is recommended that the finer mesh be specified as

slave and the coarser mesh be specified as master.

• If contact coefficients HTC/CHEAT, HCV, HNC, BNC, EMISS, and HBL are specified in both BCTABLE and BCBODY entries, the values defined in BCTABLE entry take precedence of those defined in BOBODY entry.

• The tolerances for separation distance are important to decide the thermal contact mode. The user needs to define the following two variables in BCTABLE entry:

ERROR - 4th field of the line begin with “SLAVE”

DQNEAR - 7th field of the line after the one begin with “SLAVE”

Let S be the separation distance between the two contact surfaces (computed by the program), then the thermal contact mode is decided by the following criteria.


In the above example, S=1.0, ERROR=1.5, and DQNEAR=2.0. Therefore, it is a true contact model. Note that we are mainly interested in true contact and near contact in modeling thermal contact analysis.

• To model true contact problems, HTC and ERROR fields of BCTABLE entry must be specified. The other fields in the “SLAVE” section of BCTABLE entry may be ignored.

• To model radiation across gap in near contact mode, EMISS and DQNEAR fields of BCTABLE entry must be specified. In addition, PARAM,SIGMA and PARAM,TABS must be defined.

• If HCT is specified to model the distance dependent contact analysis in near thermal contact mode, the corresponding HBL coefficient must also be specified.

• For the natural convection term in near thermal contact mode, the exponent BNC must be greater than or equal to 1.0.

• To model temperature dependent contact coefficients, specify the integer values that are equal to TABLEM1 IDs in HTC, HCV, HNC, EMISS, and/or HBL fields. The TABLEM1 entry/entries must be defined as well.

• Whenever possible, avoid the use of triangular elements for contact surface because many triangles are required for thermal contact analysis.

• For debugging purpose, it is helpful to check the jid.ink file to see which grid points are connected with CELAS2, CONV, or RADBC entries.

• We recommend that the internally generated CHBDYP elements be excluded from the HTFLOW output request.

Limitations• Higher order elements are not supported.

• Line contact is not supported.

• Thermal contact analysis is currently not supported in the MSC.Nastran Thermal Preference of MSC.Patran.

1. True Thermal Contact: S < ERROR

2. Near Thermal Contact: ERROR < S < DQNEAR

3. Far Thermal Contact: S > DQNEAR

28

• The MSC.Nastran f06 output does not display the convection heat flow for each individual convection term in near thermal contact mode. The contact thermal energies are summed together in FLUX output.

• There is no information message telling the user whether the model is in true, near, or far thermal contact.

Example ProblemsThe data files for all of the example problems contained in this Release Guide can be found in the support section of the MSC.Software website:

http://www.mscsoftware.com/support/online_ex

MSC.Nastran 2005 Release Guide+

CHAPTER

2 Thermal Analysis

■ Spatial Dependent Heat Transfer Coefficient

■ Two-Variable Heat Transfer Coefficient Tabular Function

■ Flux Output Modification for Thermal Analysis

30

2.1 Spatial Dependent Heat Transfer Coefficient

IntroductionA localized heat transfer coefficient is implemented to simulate the non-uniform free convection heat transfer across a single CHBDYi surface element. This functionality also allows users to define a constant free convection heat transfer coefficient directly in the convection property entry (PCONV), instead of referring to a material property entry (MAT4).

InputThe spatial dependent heat transfer coefficient is modeled by the modified PCONV Bulk Data entry.

Specifies the free convection boundary condition properties of a boundary condition surface element used for heat transfer analysis.

Format:

Examples:

Alternate Format and Examples:

PCONV - Convection Property Definition

1 2 3 4 5 6 7 8 9 10

PCONV PCONID MID FORM EXPF FTYPE TID

CHLEN GIDIN CE E1 E2 E3

PCONV 53 2 0 .25

PCONV 4 1 101

PCONV 38 21 2 54

2.0 235 0 1.0 0.0 0.0

1 2 3 4 5 6 7 8 9 10

PCONV PCONID MID FORM EXPF “3” H1 H2 H3

H4 H5 H6 H7 H8

31CHAPTER 2Thermal Analysis

Remarks:

1. Every surface to which free convection is to be applied must reference a PCONV entry. PCONV is referenced on the CONV Bulk Data entry.

2. MID is used to supply the convection heat transfer coefficient (H) for FTYPE=0, or the thermal conductivity (K) for FTYPE=2. MID is ignored for FTYPE=1.

3. EXPF is the free convection temperature exponent.

PCONV 20 3 10.0

PCONV 7 3 10.32 10.05 10.09

10.37

Field Contents

PCONID Convection property identification number. (Integer > 0)

MID Material property identification number. (Integer > 0)

FORM Type of formula used for free convection. (Integer 0, 1, 10, 11, 20, or 21; Default = 0)

EXPF Free convection exponent as implemented within the context of the particular form that is chosen. See Remark 3. (Real > 0.0; Default = 0.0)

FTYPE Formula type for various configurations of free convection. See Remarks 2. and 5. (Integer > 0; Default = 0)

TID Identification number of a TABLEHT entry that specifies the two-variable tabular function of the free convection heat transfer coefficient. See Remark 5. (Integer > 0 or blank)

CHLEN Characteristic length. See Remarks 6. and 8. (Real > 0.0 or blank)

GIDIN Grid ID of the referenced inlet point. See Remarks 7. and 8. (Integer > 0 or blank)

CE Coordinate system for defining the direction of boundary-layer flow. See Remarks 7. and 8. (Integer > 0; Default = 0)

Ei Component of the vector for defining the direction of boundary-layer flow in coordinate system CE. See Remarks 7. and 8. (Real or blank)

Hi Free convection heat transfer coefficient. See Remark 5. (Real for H1 and Real or blank for H2 through H8; Default for H2 through H8 is H1)

32

• If FORM = 0, 10, or 20, EXPF is an exponent of (T - TAMB), where the convective heat transfer is represented as

.

• If FORM = 1, 11, or 21,

where T represents the elemental grid point temperatures and TAMB is the associated ambient temperature.

4. FORM specifies the formula type and the reference temperature location used in calculating the convection film coefficient if FLMND = 0.

• If FORM = 0 or 1, the reference temperature is the average of element grid point temperatures (average) and the ambient point temperatures (average).

• If FORM = 10 or 11, the reference temperature is the surface temperature (average of element grid point temperatures).

• If FORM = 20 or 21, the reference temperature is the ambient temperature (average of ambient point temperatures).

5. FTYPE defines the formula type used in computing the convection heat transfer coefficient h.

• If FTYPE = 0, h is specified in the MAT4 Bulk Data entry referenced by MID.

• If FTYPE = 1, h is computed from , where f is a two-variable tabular function specified in the TABLEHT Bulk Data entry referenced by TID, is the wall temperature, and is the ambient temperature.

• If FTYPE = 2, h is computed from , where or is the Nusselt number, f is a two-variable tabular function

specified in the TABLEHT Bulk Data entry referred by TID, is the wall temperature, and is the ambient temperature.

• If FTYPE=3, hi is the free convection heat transfer coefficient applied to grid point Gi of the referenced HBDY surface element.

6. CHLEN specifies the characteristic length used to compute the average heat transfer coefficient . The following table lists typical values of CHLEN for various convection configurations.

q H= uCNTRLND T TAMB–( )EXPFT TAMB–( )⋅ ⋅ ⋅

q H= uCNTRLND TEXPF TAMBEXPF

–( )⋅ ⋅

h f Tw Ta,( )=

Tw Ta

Nu f Tw Ta,( )= NuL hL K⁄=

Nux hX K⁄=

Tw

Ta

h


7. GIDIN, CE and Ei are used to define the distance from the leading edge of heat transfer. GIDIN specifies the referenced grid ID where heat transfer starts. CE and Ei define the direction of boundary-layer flow. If CE field is blank, the default is CE=0 for basic coordinate system. If E1, E2, and E3 fields are blank, the defaults are Ei = < 1.0, 0.0, 0.0 >, i.e. the flow is in the x direction.

8. CHLEN, GIDIN, CE, and Ei are required only for free convection from flat plates with FTYPE = 2. In this case, if the heat transfer coefficient is spatial dependent, GIDIN must be specified. Otherwise, CHLEN has to be defined for the computation of average heat transfer coefficient . For free convection from tubes (CHBDYP elements with TYPE="ELCY”, “TUBE” or “FTUBE”), CHLEN, GIDIN, CE, and Ei need not be specified, because MSC.Nastran will use the average diameter of tubes as the characteristic length while computing Nu. CHLEN, GIDIN, CE, and Ei are ignored for

.

ExampleMSC.Nastran test file: spatial_h_2005.dat

Up until now MSC.Nastran used an average film coefficient definition per element. Starting with MSC.Nastran 2005 r2 you will be able to specify nodal convection coefficients. This feature will allow the mapping of each of convection coefficient from a CFD analysis into an MSC.Nastran model.

Convection Configuration Characteristic Length CHLEN

Free convection on a vertical plate or cylinder

Height of the plate or cylinder

Free convection from horizontal tubes

Diameter of the pipes

Free convection from horizontal square plates

Length of a side

Free convection from horizontal rectangular plates

Average length of four sides

Free convection from horizontal circular disks

0.9d, where d is the diameter of the disk.

Free convection from horizontal unsymmetric plates

A/P, where A is the surface area and P is the perimeter of the surface.

h

FTYPE 2≠

34

Figure 2-1 h=h(x)=2.7768/SQRT(x)

Thermal boundary conditions:

1. h =h(x)= 2.7768/SQRT(x)

2. The temperature is fixed at

3. 40 watts is applied to the 9 inch by 5 inch plate

4. At x=0, the h(x) is infinite, and therefore h(x=0.1) is used to evaluate the expression at x=0.

20°C


Figure 2-2 Thermal boundary conditions

FTYPE is added to field 6 of the PCONV entry:


Format:

If the FTYPE=3, then h1,h2,h3,h4 up to h8 can be added

In this example CHBDYG,AREA4 is used, and so up to 4 local h values can be specified per element.

pconv,1,302,0,0.0,3,8.7810,2.7768,2.7768,,8.7810pconv,2,302,0,0.0,3,2.7768,1.96349,1.96349,


1 2 3 4 5 6 7 8 9 10



36

,2.7768pconv,3,302,0,0.0,3,1.96349,1.60319,1.60319,,1.96349pconv,4,302,0,0.0,3,1.60319,1.3884,1.3884,,1.60319pconv,5,302,0,0.0,3,1.3884,1.2418,1.2418,,1.3884pconv,6,302,0,0.0,3,1.2418,1.1336,1.1336,,1.2418pconv,7,302,0,0.0,3,1.1336,1.0495,1.0495,,1.1336pconv,8,302,0,0.0,3,1.0495,.98175,.98175,,1.0495pconv,9,302,0,0.0,3,.98175,.9256,.9256,,.98175

Note that a MAT4 ID of 302 is referenced; however, this option does not require a MAT4 definition.

MSC.Nastran test file: spatial_h_2005.dat

$ NASTRAN input file created by the MSC MSC.Nastran input file$ translator ( MSC.Patran 12.0.044 ) on August 19, 2004 at 15:38:11.$ Direct Text Input for File Management Section$ Steady State Analysis, DatabaseSOL 153$ Direct Text Input for Executive ControlCENDANALYSIS = HEATTITLE = MSC.Nastran job created on 19-Aug-04 at 15:37:56ECHO = NONETEMPERATURE(INITIAL) = 1$ Direct Text Input for Global Case Control DataSUBCASE 1$ Subcase name : Default SUBTITLE=Default NLPARM = 1 SPC = 1 LOAD = 2 THERMAL(SORT1,PRINT)=ALL FLUX(SORT1,PRINT)=ALLHTFLOW=ALLBEGIN BULKPARAM POST 0PARAM AUTOSPC YESPARAM SIGMA 1.714-9NLPARM 1 0 AUTO 5 25 PW NO .001 1.-7$ Direct Text Input for Bulk Data$ Elements and Element Properties for region : platePSHELL 1 1 .1$ Pset: "plate" will be imported as: "pshell.1"CQUAD4 1 1 1 2 12 11...


...CQUAD4 45 1 49 50 60 59$ Referenced Material Records$ Material Record : k$ Description of Material : Date: 19-Aug-04 Time: 15:32:47MAT4 1 4.$ Nodes of the Entire ModelGRID 1 0. 0. 0.......GRID 60 9. 5. 0.$ Loads for Load Case : Default$ Fixed Temperatures of Load Set : 40wattSPC 1 61 1 20.$ Normal Heat Flux of Load Set : fluxQBDY3 2 .88889 100001……QBDY3 2 .88889 100045$ Convection to Ambient of Load Set : 40watt$$pconv,1,3002,0,0.0,3,0.12,0.13,0.14,$p,0.15pconv,1,302,0,0.0,3,8.7810,2.7768,2.7768,,8.7810pconv,2,302,0,0.0,3,2.7768,1.96349,1.96349,,2.7768pconv,3,302,0,0.0,3,1.96349,1.60319,1.60319,,1.96349pconv,4,302,0,0.0,3,1.60319,1.3884,1.3884,,1.60319pconv,5,302,0,0.0,3,1.3884,1.2418,1.2418,,1.3884pconv,6,302,0,0.0,3,1.2418,1.1336,1.1336,,1.2418pconv,7,302,0,0.0,3,1.1336,1.0495,1.0495,,1.1336pconv,8,302,0,0.0,3,1.0495,.98175,.98175,,1.0495pconv,9,302,0,0.0,3,.98175,.9256,.9256,,.98175$$PCONV 1 1001 0 0.CONV 100001 1 0 0 61$PCONV 2 1002 0 0.CONV 100002 2 0 0 61$PCONV 3 1003 0 0.CONV 100003 3 0 0 61$PCONV 4 1004 0 0.CONV 100004 4 0 0 61$PCONV 5 1005 0 0.CONV 100005 5 0 0 61$PCONV 6 1006 0 0.CONV 100006 6 0 0 61

38

$PCONV 7 1007 0 0.CONV 100007 7 0 0 61$PCONV 8 1008 0 0.CONV 100008 8 0 0 61$PCONV 9 1009 0 0.CONV 100009 9 0 0 61......CONV 100045 9 0 0 61$ Initial Temperatures from Temperature Load SetsTEMP 1 61 20.$ Default Initial TemperatureTEMPD 1 50.$ CHBDYG Surface ElementsCHBDYG 100001 AREA4 1 2 12 11……CHBDYG 100045 AREA4 49 50 60 59$ Free Convection Heat Transfer CoefficientsMAT4 1001 3.92699MAT4 1002 2.26725MAT4 1003 1.7562MAT4 1004 1.48426MAT4 1005 1.309MAT4 1006 1.18403MAT4 1007 1.08915MAT4 1008 1.01394MAT4 1009 .952435$ Scalar PointsSPOINT 61$ Referenced Coordinate FramesENDDATA 9c8617f3

LOAD STEP = 1.00000E+00 H E A T F L O W I N Q U A D R I L A T E R A L E L E M E N T S ( Q U A D 4 ) ELEMENT-ID SIDE HBDY-ID CONV COEFF APPLIED-LOAD CONVECTION RADIATION TOTAL 1 1 100001 5.778900E+00 8.888900E-01 -9.544129E-01 0.000000E+00 -6.552285E-02 2 1 100002 2.370145E+00 8.888900E-01 -8.710693E-01 0.000000E+00 1.782078E-02 3 1 100003 1.783340E+00 8.888900E-01 -8.793325E-01 0.000000E+00 9.557486E-03 4 1 100004 1.495795E+00 8.888900E-01 -8.833646E-01 0.000000E+00 5.525410E-03 5 1 100005 1.315100E+00 8.888900E-01 -8.852076E-01 0.000000E+00 3.682435E-03 6 1 100006 1.187700E+00 8.888900E-01 -8.860430E-01 0.000000E+00 2.847075E-03 7 1 100007 1.091550E+00 8.888900E-01 -8.859066E-01 0.000000E+00 2.983391E-03 8 1 100008 1.015625E+00 8.888900E-01 -8.832566E-01 0.000000E+00 5.633414E-03 9 1 100009 9.536750E-01 8.888900E-01 -8.714170E-01 0.000000E+00 1.747298E-02 10 1 100010 5.778900E+00 8.888900E-01 -9.544129E-01 0.000000E+00 -6.552285E-02


2.2 Two-Variable Heat Transfer Coefficient Tabular Function

IntroductionA two-variable tabular function of heat transfer coefficient, is implemented to simulate the empirical correlations for free convection. This functionality also provides the capability of modeling the free convection heat transfer on a flat plate. The heat transfer coefficient is recalculated based on element location, element temperature, and ambient temperature at each iteration or each time step.

InputThe two-variable tabular input is modeled by the new TABLEHT and TABLEH1 Bulk Data entries and the modified PCONV Bulk Data entry.

Specifies a function of two variables for convection heat transfer coefficient.

Format:

Example:

Remarks:

1. xi must be listed in ascending order.

2. At least one continuation entry must be present.

TABLEHT - Heat Transfer Coefficient Table with Two Variables

1 2 3 4 5 6 7 8 9 10

TABLEHT TID

x1 TID1 x2 TID2 x3 -etc.

TABLEHT 85

10.0 101 25.0 102 40.0 110 ENDT

Field Contents

TID Table identification number. (Integer > 0)

xi Independent variables. (Real)

TIDi Table identification numbers of TABLEH1 entries. (Integer > 0)

h Tw Ta,( )=

40

3. The end of the table is indicated by the existence of “ENDT” in either of the two fields following the last entry. An error is detected if any continuations follow the entry containing the end-of-table flag ENDT.

4. This table is referenced only by PCONV entries that define free convection boundary condition properties.

Defines a tabular function referenced by TABLEHT for convection heat transfer coefficient.

Format:

Example:

Remarks:

1. yi must be listed in ascending order.

2. At least one continuation entry must be present.

3. Any yi-fi pair may be ignored by placing “SKIP” in either of the two fields used for that entry.

4. The end of the table is indicated by the existence of “ENDT” in either of the two fields following the last entry. An error is detected if any continuations follow the entry containing the end-of-table flag ENDT.

5. TABLEH1 is used to input a curve in the form of

TABLEH1 - Heat Transfer Coefficient Table, Form 1

1 2 3 4 5 6 7 8 9 10

TABLEH1 TID

y1 f1 y2 f2 y3 -etc.=

TABLEH1 123

50.0 5.23 75.0 3.76 110.0 0.97 ENDT

Field Contents

TID Table identification number. (Integer > 0)

yi Independent variables. (Real)

fi Dependent variable. (Real)

f f y( )=


where is input to the table and is returned. The table look-up is performed using linear interpolation within the table and is evaluated at the starting or end point outside the table. No warning messages are issued if table data is input incorrectly.

6. Discontinuities are not recommended and may lead to unstable results.


Format:

Example:


1 2 3 4 5 6 7 8 9 10



PCONV 4 21 1 101

235 0 1.0 0.0 0.0

Field Contents

PCONID Convection property identification number. (Integer > 0)

MID Material property identification number. (Integer > 0)

FORM Type of formula used for free convection. (Integer 0, 1, 10, 11, 20, or 21; Default = 0)

EXPF Free convection exponent as implemented within the context of the particular form that is chosen. See Remark 3. (Real > 0.0; Default = 0.0)

FTYPE Formula type for various configurations of free convection. See Remarks 2. and 5. (Integer > 0; Default = 0)

TID Identification number of a TABLEHT entry that specifies the two-variable tabular function of the free convection heat transfer coefficient. See Remark 5. (Integer > 0 or blank)

CHLEN Characteristic length. See Remarks 6. and 8. (Real > 0.0 or blank)

GIDIN Grid ID of the referenced inlet point. See Remarks 7. and 8. (Integer > 0 or blank)

y f

42

Remarks:

1. Every surface to which free convection is to be applied must reference a PCONV entry. PCONV is referenced on the CONV Bulk Data entry.

2. MID is used to supply the convection heat transfer coefficient (H).

3. EXPF is the free convection temperature exponent.

• If FORM = 0, 10, or 20, EXPF is an exponent of (T - TAMB), where the convective heat transfer is represented as

.

• If FORM = 1, 11, or 21,

where T represents the elemental grid point temperatures and TAMB is the associated ambient temperature.

4. FORM specifies the formula type and the reference temperature location used in calculating the convection film coefficient if FLMND = 0.

• If FORM = 0 or 1, the reference temperature is the average of element grid point temperatures (average) and the ambient point temperatures (average).

• If FORM = 10 or 11, the reference temperature is the surface temperature (average of element grid point temperatures).

• If FORM = 20 or 21, the reference temperature is the ambient temperature (average of ambient point temperatures).

5. FTYPE defines the formula type used in computing the convection heat transfer coefficient h.

• If FTYPE = 0, h is specified in the MAT4 Bulk Data entry referenced by MID.

CE Coordinate system for defining the direction of boundary-layer flow. See Remarks 7. and 8. (Integer > 0; Default = 0)

Ei Component of the vector for defining the direction of boundary-layer flow in coordinate system CE. See Remarks 7. and 8. (Real or blank)

q H= uCNTRLND T TAMB–( )EXPFT TAMB–( )⋅ ⋅ ⋅

q H= uCNTRLND TEXPF TAMBEXPF

–( )⋅ ⋅


• If FTYPE = 1, h is computed from , where f is a two-variable tabular function specified in the TABLEHT Bulk Data entry referenced by TID, is the wall temperature, and is the ambient temperature.

• If FTYPE = 2, h is computed from , where or is the Nusselt number, f is a two-variable tabular function

specified in the TABLEHT Bulk Data entry referred by TID, is the wall temperature, and is the ambient temperature.

6. CHLEN specifies the characteristic length used to compute the average heat transfer coefficient . The following table lists typical values of CHLEN for various convection configurations.

7. GIDIN, CE and Ei are used to define the distance from the leading edge of heat transfer. GIDIN specifies the referenced grid ID where heat transfer starts. CE and Ei define the direction of boundary-layer flow. If CE field is blank, the default is CE=0 for basic coordinate system. If E1, E2, and E3 fields are blank, the defaults are Ei = < 1.0, 0.0, 0.0 >, i.e. the flow is in the x direction.

8. CHLEN, GIDIN, CE, and Ei are required only for free convection from flat plates with FTYPE = 2. In this case, if the heat transfer coefficient is spatial dependent, GIDIN must be specified. Otherwise, CHLEN has to be defined for the computation of average heat transfer coefficient . For free convection from tubes (CHBDYP elements with TYPE="ELCY”, “TUBE” or

Convection Configuration Characteristic Length CHLEN

Free convection on a vertical plate or cylinder

Height of the plate or cylinder

Free convection from horizontal tubes

Diameter of the pipes

Free convection from horizontal square plates

Length of a side

Free convection from horizontal rectangular plates

Average length of four sides

Free convection from horizontal circular disks

0.9d, where d is the diameter of the disk.

Free convection from horizontal unsymmetric plates

A/P, where A is the surface area and P is the perimeter of the surface.

h f Tw Ta,( )=

Tw Ta

Nu f Tw Ta,( )= NuL hL K⁄=

Nux hX K⁄=

Tw

Ta

h

h

44

“FTUBE”), CHLEN, GIDIN, CE, and Ei need not be specified, because MSC.Nastran will use the average diameter of tubes as the characteristic length while computing Nu. CHLEN, GIDIN, CE, and Ei are ignored for

.

Basic Theory and Methods The distributed free convection heat flow on a particular grid of a CONV element is computed by

if FORM = 0 and EXPF = 0.0

where hi or = function of and , is the temperature of the grid, and Tai is the temperature of the corresponding ambient node.

For example, if , , and the model is defined by the following Bulk Data entries.

Then the heat transfer coefficient hi is equal to

If the heat transfer coefficient is computed from the Nusselt number (FTYPE=2 in PCONV entry), the distance d from the leading edge of heat transfer is computed as follows.

1 2 3 4 5 6 7 8 9 10

PCONV 10 1 101

TABLEHT 101

40.0 1004 60.0 1006 ENDT

TABLEH1 1004

10.0 3.74 20.0 2.14 30.0 0.94 ENDT

TABLEH1 1006

10.0 4.16 20.0 2.96 30.0 1.56 ENDT

FTYPE 2≠

i h– iAiucntr dln Twi Tai–( )=

Nui Twi Tai Twi

Twi 42.0= Tai 25.0=

0.5 2.14 0.94+( ) 60.0 42.0–( )60.0 40.0–( )--------------------------------- 0.5+ 2.96 1.56+( ) 42.0 40.0–( )

60.0 40.0–( )---------------------------------⋅ ⋅ ⋅ ⋅

Nux


Where A is the location of GINDIN, B is the centroid of the convection element, and is the unit vector in the direction of boundary-layer flow.

Example – Free Convection of a Horizontal Cylinder (fconv_axi_2dtable.dat) This example (see examples folder for input file) demonstrates the application of a 2D table to specify free convection heat transfer coefficient. In this problem, a horizontal cylinder with 0.3048 m in diameter and 0.3 m in length has a heat flux of 7000 W/m2 applied on one end cap. The heat is lost by free convection through the outside surface of the cylinder to the ambient air at 15 oC.

Under laminar condition, the heat transfer coefficient for free convection to air at atmospheric pressure is equal to

Using the above equation, a 2D table is computed with the following data.

A

B

d

e

d AB= e⋅

e

h 1.32 ∆T D⁄( )0.25 1.32 0.3048⁄( ) Tw Ta–( )0.25 1.77652 Tw Ta–( )0.25= = =

Tw 100°C= Ta 15°C= h 5.3942W m2⁄ °C⋅=

Tw 150°C= Ta 15°C= h 6.0555W m2⁄ °C⋅=

Tw 200°C= Ta 15°C= h 6.5518W m2⁄ °C⋅=

Tw 250°C= Ta 15°C= h 6.9556W m2⁄ °C⋅=

Tw 300°C= Ta 15°C= h 7.2993W m2⁄ °C⋅=

46

These data are converted into PCONV, TABLEHT, and TABLEH1 Bulk Data entries listed as follows.

PCONV,1,,,,1,101TABLEHT,101,100.0,1001,150.0,1002,200.0,1003,250.0,1004,300.0,1005,endtTABLEH1,1001,15.0,5.3942,30.0,5.3942,endtTABLEH1,1002,15.0,6.0555,30.0,6.0555,endtTABLEH1,1003,15.0,6.5518,30.0,6.5518,endtTABLEH1,1004,15.0,6.9556,30.0,6.9556,endtTABLEH1,1005,15.0,7.2993,30.0,7.2993,endt

The analysis results using an axi-symmetric model with 6-node CTRIAX6 elements are shown below.


2.3 Flux Output Modification for Thermal Analysis

IntroductionThe data recovery of MSC.Nastran Thermal Analysis is enhanced by implementing the heat flow output of structural elements. This functionality relates the heat flow output of CHBDYE, CHBDYG, and CHBDYP elements to the structural elements so that users can check the heat balance of the models. The new output also includes convection heat transfer coefficients and side identification numbers to facilitate model checking.

Input The heat flow output of structural elements is requested by the new HTFLOW Case Control command.

Requests heat flow output at selected structural elements.

Format:

Example:

HTFLOW = ALLHTFLOW = 15

HTFLOW - Elemental Heat Flow Output Request

Describer Meaning

PRINT The printer will be the output medium.

NOPRINT Generate, but do not print out, the output.

PUNCH The punch file will be the output medium.

ALL Heat flow for all structural elements will be output.

n Set identification of previously appearing SET command. Only structural elements with identification numbers that appear on this SET command will be included in the heat flow output. (Integer>0)

HTFLOW PRINT, PUNCHNOPRINT

ALL

n

=

48

Remarks:

1. Elemental heat flow output is available for steady state thermal analysis (SOL 101 and SOL 153) and transient thermal analysis (SOL 159).

2. Heat flow is computed from the applied heat loads and the effect of convection and radiation heat transfer on boundary (CHBDYE, CHBDYG, and CHBDYP) elements.

3. See Remarks 6-8 of the descriptions of CHBDYE Bulk Data for the side conventions of solid elements, shell elements, and line elements.

OutputThe output data are grouped by types of structural elements. A sample output is listed below.

The side IDs are consistent with the side conventions of the CHBDYE elements. In the above case, side 1 is the surface of shell elements while sides 2-5 are the four edges of quadrilateral elements.

Basic Theory and MethodsThe formulae used to compute various kinds of heat flow are listed below.

• Free convection if FORM = 0, 10, or 20

if FORM = 1, 11, or 20

• Forced Convection

if FORM = 0, 10, or 20

if FORM = 1, 11, or 21

• Boundary Radiation

H E A T F L O W I N H E X A H E D R O N S O L I D E L E M E N T S ( H E X A ) ELEMENT-ID SIDE HBDY-ID CONV COEFF APPLIED-LOAD CONVECTION RADIATION TOTAL 45 6 451 1.000000E+00 0.000000E+00 -6.892015E+00 -1.159713E+01 -1.848914E+01 5 452 1.000000E+00 0.000000E+00 -7.442470E+00 -1.256259E+01 -2.000506E+01 1 453 1.000000E+00 0.000000E+00 -6.891933E+00 -1.159698E+01 -1.848892E+01 2 454 1.000000E+00 0.000000E+00 -6.846252E+00 -1.151713E+01 -1.836338E+01 46 6 461 1.000000E+00 0.000000E+00 -6.136873E+00 -1.028224E+01 -1.641911E+01 5 462 1.000000E+00 0.000000E+00 -6.341478E+00 -1.063741E+01 -1.697889E+01 1 463 1.000000E+00 0.000000E+00 -6.136881E+00 -1.028225E+01 -1.641913E+01 2 464 1.000000E+00 0.000000E+00 -6.095622E+00 -1.021073E+01 -1.630635E+01 3 465 1.000000E+00 0.000000E+00 -5.932276E+00 -9.927887E+00 -1.586016E+01

F hA–= ucntr dln T Ta–( ) fexpT Ta–( )⋅ ⋅

F hA–= ucntr dln Tfexp

Tafexp

–( )⋅ ⋅

F hA T Ta–( )–=

h coef= Rerexp

Prpexp⋅ ⋅

h coef= Rerexp

Prpexp K

D----⋅⋅ ⋅

F σA–= FAMB ucntr dln εT4 αTa

4–( )⋅ ⋅ ⋅


• Enclosure Radiation

• Applied Heat Flux

• Directional Heat Flux

where:

= the heat flow across the selected boundary element

= the convection heat transfer coefficient

= the area associated with the selected boundary element

= the temperature of the control node

= the wall temperature

= the ambient temperature

= the Reynolds number

= the Prandtl number

= the thermal conductivity

= the average diameter or the characteristic length

= the Stefan-Boltzmann constant

= the radiation view factor between the surface and the ambient point

= the emissivity of the selected boundary element

= the absorptivity of the selected boundary element

= the grid point temperatures to element temperatures transformation matrix

= the element radiation matrix

= the temperature origin in absolute scale

= the heat flux applied to the selected boundary element.

= the vector of the radiation beam

= the outward surface normal vector

F Gge[ ] Re[ ]{ } TT Tabs+( )4

–=

F q0A= ucntr dln⋅

F α–= e n⋅( ) q0A ucntr dln⋅ ⋅ ⋅

F

h

A

ucntr dln

T

Ta

Re

Pr

K

D

σ

FAMB

ε

α

Gge[ ]

Re[ ]

Tabs

q0

e

n

50

Example – Free Convection of a Cube (fconv_cube.dat) This example demonstrates the heat flow output of a HEXA element requested by the HTFLOW Case Control command. In this problem, a cube with 0.20 m in each side is maintained at 60 oC and is exposed to air at 10 oC. The thermal conductivity of the cube is equal to 0.02685 , while the heat transfer coefficient between the cube and the air is 9.07 .

The heat flow across each face of the cube can be computed as follows.

The MSC.Nastran input file is shown below.

SOL 153CENDANALYSIS = HEATTITLE = EXAMPLE HTFLOW REQUESTTEMPERATURE(INITIAL) = 1SUBCASE 1$ Subcase name : Default SUBTITLE=Default NLPARM = 1 SPC = 1 THERMAL=ALL HTFLOW=ALLBEGIN BULKNLPARM 1 0 AUTO 5 25 PW NO .001 1.-7$ Elements and Element Properties for region : solidPSOLID 1 1 0$ Pset: "solid" will be imported as: "psolid.1"CHEXA 1 1 1 2 4 3 5 6 8 7$ Referenced Material Records$ Material Record : alum$ Description of Material : Date: 01-Apr-04 Time: 23:04:54MAT4 1 204. 896. 2707.$ Nodes of the Entire ModelGRID 1 0. 0. 0.GRID 2 .2 0. 0.GRID 3 0. .2 0.GRID 4 .2 .2 0.GRID 5 0. 0. .2GRID 6 .2 0. .2GRID 7 0. .2 .2GRID 8 .2 .2 .2GRID* 999 .256948 .140484* -.026591$ Loads for Load Case : Default$ Fixed Temperatures of Load Set : fixSPC 1 1 1 60. 2 1 60.

W/m °C⋅W/m2 °C⋅

F hA Tw Ta–( )– 9.07–= = 0.04 60 10–( )⋅ ⋅ 18.14W–=


SPC 1 3 1 60. 4 1 60.SPC 1 5 1 60. 6 1 60.SPC 1 7 1 60. 8 1 60.$ Fixed Temperatures of Load Set : convSPC 1 1000 1 10.$ Convection to Ambient of Load Set : convPCONV 1 1001 0 0.CONV 100001 1 0 0 1000CONV 100002 1 0 0 1000CONV 100003 1 0 0 1000CONV 100004 1 0 0 1000CONV 100005 1 0 0 1000CONV 100006 1 0 0 1000$ Initial Temperatures from Temperature Load SetsTEMP 1 1 60. 2 60. 3 60.TEMP 1 4 60. 5 60. 6 60.TEMP 1 7 60. 8 60. 1000 10.$ Default Initial TemperatureTEMPD 1 0.$ CHBDYG Surface ElementsCHBDYG 100001 AREA4 1 2 6 5CHBDYG 100002 AREA4 3 7 8 4CHBDYG 100003 AREA4 1 3 4 2CHBDYG 100004 AREA4 2 4 8 6CHBDYG 100005 AREA4 6 8 7 5CHBDYG 100006 AREA4 5 7 3 1$ Free Convection Heat Transfer CoefficientsMAT4 1001 0.02685 9.07$ Scalar PointsSPOINT 1000ENDDATA

The output data from HTFLOW request are listed in the following.

H E A T F L O W I N H E X A H E D R O N S O L I D E L E M E N T S ( H E X A ) ELEMENT-ID SIDE HBDY-ID CONV COEFF APPLIED-LOAD CONVECTION RADIATION TOTAL 1 2 100001 9.070000E+00 0.000000E+00 -1.814000E+01 0.000000E+00 -1.814000E+014 100002 9.070000E+00 0.000000E+00 -1.814000E+01 0.000000E+00 -1.814000E+01 1 100003 9.070000E+00 0.000000E+00 -1.814000E+01 0.000000E+00 -1.814000E+01 3 100004 9.070000E+00 0.000000E+00 -1.814000E+01 0.000000E+00 -1.814000E+01 6 100005 9.070000E+00 0.000000E+00 -1.814000E+01 0.000000E+00 -1.814000E+01 5 100006 9.070000E+00 0.000000E+00 -1.814000E+01 0.000000E+00 -1.814000E+01

52

where:

Guidelines• If HTFLOW is specified, users may avoid duplicate heat flow output by

specifying FLUX=NONE or omitting the FLUX command. This will reduce processing time and the sizes of output data for big models.

• When CONVM elements are used to model fluid flow, the HTFLOW output will not show the heat flow from forced convection unless there exists dummy CROD elements associated with the CHBDYP elements. In this case, it is recommended to use the original FLUX command to view the heat flow output.

• The HTFLOW command only outputs the heat flow of the boundary elements (CHBDYE, CHBDYG, and CHBDYP) that are associated with the surfaces, edges, or points of the selected structural elements. The following table lists the associated boundary elements for each kind of structural elements.

APPLIED-LOAD Heat flow from applied heat flux (QBDY1, QBDY2, QBDY3, and QVECT).

CONVECTION Heat flow from free convection (CONV) and forced convection (CONVM).

RADIATION Heat flow from boundary radiation (RADBC) and enclosure radiation (RADSET).

TOTAL Total heat flow (sum of the above three entities).

Structural Elements Boundary Elements

Solid elements:CHEXA, CPENTA, and CTETRA.

CHBDYECHBDYG (AREA3, AREA4, AREA6, and AREA8)

Shell elements:CQUAD4, CQUAD8, CTRIA3, and CTRIA6.

CHBDYECHBDYG (AREA3, AREA4, AREA6, and AREA8)CHBDYP (LINE, ELCYL, FTUBE, and TUBE)


Line elements:CROD, CONROD, CBAR, CBEAM, CTUBE, and CBEND.

CHBDYP (LINE, ELCYL, FUTPBE, TUBE, and POINT)

Axisymmetric elements:CTRIAX6

CHBDYECHBDYG (REV)

Structural Elements Boundary Elements

54

I N D E XMSC.Nastran Release Guide

I N D E XMSC.Nastran Release Guide

BBFRIC Bulk Data entry

specification of, 15Bulk Data Entries

PCONV, 30TABLEH1, 39, 40TABLEHT, 39

CCase Control Commands

HTFLOW, 47CHBDYi surface element, 30convection heat transfer coefficients, 47

FFlux Output, 47free convection heat transfer, 39

Hheat flow output, 47heat transfer coefficient, 30, 39

Nnodal convection coefficients, 33non-uniform free convection heat transfer,

30

PParameters

PCONV, 30, 35, 41PCONV Bulk Data entry

specification of, 41

Sspatial dependent heat transfer coefficient,

30

INDEX56

Documents

MSC.Nastran 2005 r2 Release Guide Addendum