微型燃气轮机是微小型分布式供能系统的核心设备，叶片扩压器对于微型燃机离心压气机的性能有重要影响。该文对某kW级微型燃机的扩压器进行了设计，对带扩压器的微型离心压气机进行数值模拟，着重探讨了扩压器进口冲角对压气机性能的影响。数值模拟结果表明，扩压器进口负冲角很大时，在小流量的工况下压比和效率很高，在大流量工况下压比和效率迅速降低，特性曲线陡峭，工作范围变窄。扩压器进口冲角绝对值较小时，压气机特性曲线较为平坦，工作范围宽广，冲角的较小变化对于压气机性能的影响不显著；正冲角情况下，扩压器的静压恢复系数最高，负冲角越大，静压恢复系数越小。由此可见，扩压器进口冲角的最优值并不固定，应当根据压气机具体工作要求进行选择，同时还需要考虑为保证燃烧器有较高的燃烧效率而带来的对静压恢复系数的要求。

Micro gas turbine is the core device of micro distributed energy system, and the vaned diffuser has significant influence on the compressor performance of micro gas turbine. The diffuser of a kW-class micro gas turbine was designed, and the numerical simulation was made on the micro compressor with vaned diffuser, especially the influence of vane incidence on the compressor performance. The results show that the pressure ratio and efficiency of compressor are very high in the case of large negative incidence at small flow rate, while the parameters drop quickly at large flow-rate condition with steep characteristic curve and narrowed working range. When the absolute value of diffuser incidence is relative small, the compressor shows a relative flat characteristic curve and wide working range. The slight variation of incidence contributes less to the performance of compressor. The static recovery coefficient is higher under positive incidence condition, and it becomes lower as the incidence decreases. The optimum incidence of vaned diffuser is not fixed and should be determined according to the specific working condition and the requirements for higher combustion efficiency.