微型燃气轮机向心透平导向器的流场分析与设计研究

对微型燃气轮机向心透平导向器叶片型线的设计原则进行了探讨,设计出了5种尾缘厚度的导向器叶片,并分别对其通道流场进行了全三维黏性数值模拟.研究结果表明:以该型线设计原则设计出的高亚音速向心透平导向器叶片具有较高的流动效率,并且可以有效减小向心透平的径向尺寸;尾缘相对厚度对导向器叶片流动特性及效率影响较大,尾缘相对厚度每增加1%.叶轮进口气流角将减小约0.03°,速度系数将降低约0.1%.考虑到目前高温合金精密铸造的工艺水平,导向器叶片尾缘厚度取0.6~1.0 mm、尾缘相对厚度小于15%可以获得较高的气动性能.

Flow Analysis and Design of Radial Inflow Turbine Guide Vanes for Microturbine

The general design principles on shape-design of radial inflow turbine guide vanes were discussed. Five kinds of guide vanes were designed with different thickness of trailing edges, and the flow fields in the guide vanes passage were investigated by 3-dimensional viscous numerical simulation. The results indicate that with the present general design principles for radial inflow turbine guide vanes, high flow efficiency of the high-subsonic guide vane can be obtained, and the radius of the radial inflow turbine can be reduced effectively. Relative thickness of the trailing edge has important impact on flow efficiency and characteristics. If relative thickness of trailing edge increases 1%, inlet flow angle of the impeller will reduce 0.03 degree and velocity coefficient of the guide vanes will reduce 0.1%. Therefore, in order to achieve high aerodynamic performance the thickness of trailing edge of guide vanes should be within the range of 0.6 to 1.0 millimeter and the relative thickness of trailing edge less than 15%, based on the present study with consideration on the available super alloy cast technology.