摘要：The shear-stress transport(SST)turbulence model is incorporated into Navier-Stokes equations to simulate a turbomachinery flowfield.A staggered finite volume method is used to make the mean flow equations and turbulence model equations strongly coupled and enhance the stability of the numerical *** implicit treatment of the source terms is applied to the SST model.A steady state solution is obtained using five-stage Runge-Kutta time-stepping scheme with local time stepping and residual smoothing to accelerate convergence. The wall distance d,a key parameter in the SST model,is solved by a partial differential *** validations of the code are conducted on rotor 37,wp11 at design and off-design conditions by comparison with measurements and the Spalart-Allmaras(SA)turbulence *** flow within the tip is calculated with a multi-block grid.

摘要：It is one of the most efficient ways to greatly improve aero-engines' performance by utilizing vaneless counterrotating turbine(VCRT) *** supply sufficient power,VCRT turns to be high Mach number,large flow angle at high-pressure turbine(HPT) rotor exit,and low blade camber angle,which increase difficulties to turbine *** the axial velocity ratio of HPT rotor is much larger than the conventional ones,the optimal selection of VCRT velocity triangles based on theoretical analysis is developed,and how the efficiency varied by HPT stator/rotor exit flow angle is also figured *** key points to design a high efficient practicable VCRT are to select velocity triangles that are characterized by low flow coefficient,high outlet flow angle and large axial velocity ratio of HPT ***,performance comparison between convergent blade and convergent-divergent blade shows the latter is more appropriate for VCRT.