A NUMERICAL SIMULATION OF 3D VISCID STEADY FLOW IN A TURBINE STAGE

A 3D numerical methodology is presented for simulating blade rows in a turbine stage by solving 3D time-dependent compressible Navier-Stockes equations.This numerical method is based on Godnov's finite volume scheme with third-order-accuracy and TVD property.Baldwin-Lomax algebraic turbulence model is employed to simulate largely separated flow.The principal assumptions are made as follows:the flow is steady between stator and rotor and these rows can communicate via inter-row mixing plane.These reformative "mixing planes" introduce circumferential averaging of flow properties but preserve general radial variations.The circumferential disequilibrium in the same row is assured by using non-reflecting extrapolated boundary condition.In view of wide working temperature range in turbine stage,varying specific heat is applied in this method.The calculation instability resulted from inter-row mixing treatment is improved remarkably by using Riemann solver and lax gene in the case of small inter-row gap.The application of this method is illustrated for an axial high-pressure turbine stage in an areoengine.The results show that this method not only is available but also reveals flow phenomenon in rows very well.