关键词: 对转涡轮+;激波;叶型;流场数值模拟

Abstract: In order to reveal the flow characteristics in a VCRT,a three-dimentional,viscous,steady CFD analysis was performed for investigating the turbine performance.Results show that the performance of this VCRT basically reaches the original objective,which indicates that a convergent-divergent blade passage in the high pressure rotor and a convergent-divergent meridian plane of the VCRT are suitable for the VCRT.All of these blade rows of the VCRT,especially high pressure rotor,need much more optimization.The efficiency of the VCRT can be improved through some optimized methods,such as blade curving,throat location adjusting,and so on.The results of the numerical simulations also show that the pitch-averaged Mach number of the outflow of the high pressure rotor is about from 1.4 at the hub to 1.6 at the shroud.The strength of oblique shock waves is strongest on the midspan in the trailing edge of the high pressure rotor.However,it is weaker on the hub and the shroud.Meantime,the results also indicate that the performance of the VCRT will decrease with the increase of the outlet pressure.The performance of the high pressure rotor is retained with the change of outlet pressure.However,performance of the low pressure rotor is greatly influenced with the change of outlet pressure.

Key words: Counter-rotating turbine~+;Shock wave;Blade airfoil;Flow field numerical simulation