某MW级燃机非对称排气道性能分析

Performance Analysis of Non-Symmetric Exhaust Duct in A MW-Level Gas Turbine

针对某MW级燃机动力透平及非对称排气道,本文采用CFD方法首先单独研究了不同进口条件下排气道的性能,发现该排气道性能良好,总压损失较低,且对15°以内的入口旋流角具有较好的适应性。由于动力透平与排气道之间存在相互作用,将整周动力透平与排气道进行耦合计算,发现由于动力透平设计存在一定的缺陷,单级计算时动叶根部存在大范围的气流分离,与排气道耦合后,透平功率略有下降,但动叶根部气流展向分离范围有所减小,且分离程度出现周向不均匀现象;同时,由于气流分离导致动力透平出口气流的旋流角较大,耦合条件下排气道性能明显恶化,总压损失增加较大。

According to the power turbine and non-symmetric exhaust duct, the duct performance at different inlet boundary conditions is studied using CFD method, and the duct turns out to perform well with a low total pressure loss and good adaptability to inlet swirl less than 15 degree. As the interaction between power turbine and duct, coupled calculation is needed. Result shows that large separa- tion exists near the rotor blade root due to the irrational design of power turbine . When coupled with duct, the power of turbine decrea- ses a little and the spanwise separation range is smaller with circumferential variations occurred. Meanwhile, the coupled performance of duct deteriorated seriously due to the large inlet swirl caused by the separation in rotor.