NUMERICAL PREDICTION OF SECONDARY FLOW LOSS IN A TURBINE CASCADE BY USING TVD SCHEME TO SOLVE N-S EQUATIONS

Harten's TVD scheme and Baldwin-Lomax turbulence model are applied to solving 3D N-S Equations for simulation of emergence and development of secondary flow and its loss in a rectilinear turbine cascade at a-8° incidence.The computation simulates successfully the vortex structure of the secondary flow and its loss distribution in the cascade passage.The predicted pitch averaged cascade distribution along blade height is consistent with the experimental data well.The mechanism of secondary flow loss emergence and development is revealed.It is found out that the incoming endwall boundary layer,the horse shoe vortex and its induced separation,and the shear motion of the horse shoe vortex with that of passage vortex are the major sources of the loss production,and the cascade boundary layer development and the passage vortex play an important role in the cascade loss development and redistribution.As a result,the numerical technique developed by the authors has a high accuracy and resolution,and can be adopted in the engineering application.