The “Virtual Manikin” ProjectThe “Virtual Manikin” Project
Andy Buxton
Adrian Huggins
&
David Glynn
The Defence Evaluation & Research Agency The Defence Evaluation & Research Agency The Defence Evaluation & Research Agency The Defence Evaluation & Research Agency
This work was carried out as part of Technology Group 5 (Human Sciences and Synthetic Environments) of the MoD Corporate Research Programme
DERA’s Ultimate Customers: DERA’s Ultimate Customers: the Front Linethe Front Line
Fundamentals of heat stressFundamentals of heat stress
Climate Clothing
Physical work
Experiment or Model?Experiment or Model?
Experimental methods– Laboratory or field based
Expensive Specific Possibly hazardous
Instrumented manikins for clothing Instrumented manikins for clothing evaluationevaluation
Thermal manikin– Thermal resistance (insulation)
‘Sweating’ manikin– Evaporative resistance
Virtual Manikin Project ObjectivesVirtual Manikin Project Objectives
Create a tool for modelling and assessing potentially
hazardous environments
Create a tool for assessing clothing systems prior to
construction
Reduce costs and time-scales for equipment
procurement
Geometry - STL file produced by laser Geometry - STL file produced by laser scanningscanning
Cartesian grid detailsCartesian grid details
Grid dimension– 38x52x56
Domain dimension– 2.5 x 2.0 x 1.9 m
Boundary Conditions & Source TermsBoundary Conditions & Source Terms
Open pressure boundary conditions at front, sides and top of domain
Inlet boundary condition specified at front for “forced convection” case
Initial and inlet temperatures 20oC Bouyancy forces represented
using Boussinesq model k-e turbulence model used Manikin heat source:
CO=1.E+5,VAL=34oC
Air movement and temperature contoursAir movement and temperature contours
Predicted manikin heat loss Predicted manikin heat loss
120
140
160
180
200
220
240
0 0.5 1 1.5 2
Air speed (ms-1)
Pre
dic
ted
hea
t lo
ss f
rom
man
ikin
(w
atts
)
Human thermo-physiological modelHuman thermo-physiological model
Information exchangeInformation exchange
Virtual Manikin-CFD model
calculates local boundary
conditions for physiological
model
Physiological model dictates
heat and mass (sweat)
sources for the CFD model
Virtual Manikin - CFD model
Thermo-physiological model
Information flowInformation flow
Flow calculation
Calculation of local boundary
conditions
2-D Thermal model
Calculation of segmental heat
and mass sources
Initial conditions
CFD model
Current PARSOL treatmentCurrent PARSOL treatment
PARSOL currently treats fluid flow differently from heat transfer (see figures)
Fluid - Solid interfaces are treated correctly as a “spline” for fluid flow and as a “staircase” for heat transfer
There can only be one fluid- solid interface in a given mesh cell
SOLID
FLUID
SOLID
FLUID
Extended PARSOL treatmentExtended PARSOL treatment
FluidFluid
SolidSolid
FluidFluid
Clothing simulationClothing simulation
The clothing model will require integration of a number of features in PHOENICS
– Moving objects– Stress-Strain– Fluid flow– Heat transfer
Pre-existing algorithms will be used for the deformation of clothing
Summary - 1Summary - 1
An STL file of a manikin was produced by laser scanning
This was imported into PHOENICS Flow simulations were produced and heat transfer
predictions made Further grid refinement is required A parallel cluster of PCs will be used for future work
Summary - 2Summary - 2
The CFD model will be linked to a human thermo-physiological model
More complex environments will be evaluated, e.g. vehicles, aircraft
PARSOL will be enhanced:-– Unify current treatment of Fluid Flow and Heat Transfer
– Extend PARSOL to allow multiple interfaces in any given cell
– The extended PARSOL feature will be available to all PHOENICS users
Points of contactPoints of contact
Andy Buxton, David Glynn,
Protection and Performance Department, Flowsolve Ltd.
Centre for Human Sciences, Arthur Road,
DERA, Ively Road, Wimbledon Park,
HANTS. GU14 OLX. Tel. +44 208 944 0940
United Kingdom Fax. +44 208 944 1218
Tel. +44 1252 393626 [email protected]
Fax +44 1252 392097
email: [email protected]