Endwall Contouring, Using Continuous Diffusion Technology, A Breakthrough Technology and its Application to a Three-Stage High Pressure Turbine Introduced

Endwall Contouring, Using Continuous Diffusion Technology, A Breakthrough Technology and its Application to a Three-Stage

High Pressure Turbine

Introduced byTurbomachinery Performance and Flow Research Laboratory,

Texas A&M University

Sponsored by DOE, National Energy Technology Laboratory

Efficiency Improvement by Endwall Contouring

TPFL: The Turbomachinery Performance and Flow Research LaboratoryTexas A&M University

M. T. Schobeiri

Project DE-FOA-0000031ASME-IGTI-2011

June 06-10


M. T. Schobeiri

Pressure difference between suction and pressure side causes:

•Systems of secondary vortices•Generation of induced drag forces•Total pressure reduction•Secondary flow losses•Efficiency decrease

Introduction: Endwall Secondary Flow, Reduction


June 06-10


M. T. Schobeiri

Breakthrough Technology, Disclosure of Invention TAMUS 3259

Unlike methods available in the literature, the Continuous Diffusion

Technology introduced by TPFL is physics based and can be applied to

P, IP, and LP turbines and compressors regardless the load coefficient,

flow coefficient and degree of reaction. Details are explained in the

ASME paper GT2011-45931 Presented at the ASME-IGTI-Turbo-Expo

2011, June 06-10, 2011, Vancouver, Canada


June 06-10


M. T. Schobeiri

TPFL Research Turbine Used for Endwall Contouring Research

A Three-stage Turbine Rotor with two Independent Coolant Flow Loops

Mainstream Flow

Rotor-Seal Ejection Cooling

Platform Discrete Hole Film Cooling

Tow Independent Coolant Loops for Coolant Injection from Stator-Rotor Seal and Downstream Film Cooling

Holes


June 06-10

Numerical Methodology

Steady state models used, convergence was assessed through monitoring of:

Equation RMS and maximum residual values Inlet and exit mass flow Area-averaged pressure and velocity at turbine exit

Turbulence model

Shear Stress Transport (SST) model CFX Automatic wall treatment employed

Switches between wall functions to a low-Reynolds number near wall formulation

Requires y+<2, and at least near-wall nodes

Boundary conditions Ptin, Ttin, Pb Fixed rotation speed Adiabatic and non-slip conditions on the wallTPFL: The Turbomachinery Performance and Flow Research Laboratory

Texas A&M University


June 06-10

Numerical Simulation Mesh

Rotor mesh has over 2 million elements Extensive grid sensitivity tests Wall regions use 22 nodes The entire model involves over 9 million elements


M. T. Schobeiri


June 06-10

Blade Loading of Second Rotor


M. T. Schobeiri

Blade Loading at Hub

pinew

pitarget

piref

Target Pressure Range

Nomalized axial chord

Pre

ssu

re[P

a]

0 0.25 0.5 0.75 1

80000

82000

84000

86000

reference casenew contouring

Geometry needs to be further optimized.

Geometry needs to be further optimized


June 06-10

Blade Loading of Second Rotor

Pressure distribution at two different span locations


M. T. Schobeiri

Geometry needs to be further optimized.

Blade Loading at Hub Blade Loading at 2% SpanRad distance from hub

1.3 mm


June 06-10

Continuous Diffusion Technology Applied to Endwall sign

The design of contouring considers both the direction of streamlines and pressure gradient near hub. Currently there is no positive portion.


M. T. Schobeiri


June 06-10

Pressure Distribution at Hub

Comparison of pressure distributions


M. T. Schobeiri

reference case partial contouring extended

new contouring


June 06-10

Total Pressure Loss Coefficient for Second Rotor


M. T. Schobeiri

Normalized span

Pt

0 0.1 0.2 0.3 0.4 0.50.00

0.05

0.10

0.15

0.20

reference casenew contouring

Mass-Averaged Total Pressure Loss Coefficient at x=1.07Cax


June 06-10


M. T. Schobeiri

Efficiency Improvement Using New Technology

From Literature

TPFL Conventional Designs

Documents

Endwall Contouring, Using Continuous Diffusion Technology, A Breakthrough Technology and its Application to a Three-Stage High Pressure Turbine Introduced