Numerical Study of Effect of Turbulence at Entrance on Flow Within Turbine Cascades

The turbulent flow within cascades of VKI low speed axial turbine is being numerically investigated with Navier-Stokes equations by respectively making use of Spalart-Allmaras and k-eps turbulence models. Both the calculation results, obtained by using respectively the two models, agree with experiments. Composition and distribution of the cascade's flow losses, as well as calculation accuracy, depend in the main on boundary layer conditions at entrance. End wall losses are mainly caused by the boundary layer at entrance. Under high velocity flow conditions, cascade losses are mainly caused by radial drift of the boundary layer along the suction surface and by blade wakes. Figs 14 and refs 8.