壁面粗糙度对轴流压气机气动性能的影响

Effect of Wall Roughness on Aerodynamic Performance of Axial Compressors

以某典型压气机级为研究对象,利用三维数值模拟方法系统、定量地研究了壁面粗糙度变化对轴流压气机气动性能的影响,揭示了壁面粗糙导致压气机性能退化的内在机制。结果表明:壁面粗糙度增大会降低压气机总压比和等熵效率,且粗糙度越大,性能衰退越快;当壁面粗糙度超过90μm时,压气机的总压比和等熵效率分别下降2.58%和7.15%;近壁区气流的黏性耗散,分离区气流掺混、堵塞的增强,以及激波损失是导致压气机性能退化的主要原因;壁面粗糙度增大将使压气机特性线向流量减小的方向移动,近失速点的特性参数减小得更快,压气机的稳定工况范围有所增大,但通流能力大幅降低;当壁面粗糙度超过150μm时,失速工况提前发生,压气机稳定工作范围迅速减小6.21%。

A typical compressor stage was taken as the research object and the effect of wall roughness variation on the aerodynamic performance of axial compressor was investigated quantitatively with a three dimensional numerical simulation.The underlying mechanism of compressor performance degradation caused by wall roughness was revealed.The results show that the increasing wall roughness reduces total pressure ratio and the isentropic efficiency of compressors,and the greater the roughness,the faster the performance degradation.When the wall roughness exceeds 90μm,the total pressure ratio and isentropic efficiency of compressors decrease by 2.58% and 7.15% respectively.The viscous dissipation of airflow in near wall region,enhancement of the mixing and blockage of airflow in the separation zone and loss of the shock wave are the main reasons of worsened compressor performance.In addition,with the increasing wall roughness,compressor characteristic curves move toward mass flow decreasing direction,and characteristic parameters near stall point decrease faster.The steady working range of compressors is thus widened,but flow capacity is greatly lowered.When wall roughnessexceeds 150 μm,stall condition occurs in advance,and compressor steady working range is rapidly reduced by 6.21%.