来流湍流度及端壁效应对涡轮叶片上对流换热的影响

利用大尺寸低速开式叶栅风洞对涡轮叶片表面的对流换热进行了实验测量，叶片高度方向布置了３个测量位置，距端壁距离分别为５ｍｍ，３０ｍｍ及１５０ｍｍ。重点对比研究了高来流湍流度、端壁效应及来流雷诺数对涡叶片中部及根部区的过渡起始点、过渡区长度及换热的影响。实验参数范围是：来流湍流度Ｔｕ＝０．７５～１３．５％，来流雷诺数Ｒｅ＝６００００～２４００００。

INFLUENCES OF MAINSTREAM TURBULENCE AND END-WALL EFFECT ON CONVECTIVE HEAT TRANSFER OF TURBINE BLADE

The influences of mainstream turbulence,end-wall effect and mainstream Reynolds number on the beginning location of transition,transition length and heat transfer both in the middle region and root region of a turbine blade were comparatively studied.A five-blade linear cascade in a large-scale low-speed opening wind tunnel was used in the experiment.A thin-foil thermocouple technique was applied to determining the heat transfer coefficients on the blade surface.Three row of thermocouple located 5 mm,30 mm and 150 mm in the span-wise direction of blade from end-wall.The mainstream Reynolds number changed from 60000 to 240000.The mainstream turbulence varied from 0 75% to 13 5%.The results showed that the mainstream turbulence enhanced heat transfer coefficients on the suction surface to a great extent,and also increased the heat transfer coefficients on the pressure surface.Both onset and end of transition on the suction surface boundary layer move forward with increase of mainstream turbulence intensity.The end-wall effect region emerged at the root region of x/C >0 24 of suction surface for the present turbine blade.The end-wall effect raised on the heat transfer coefficients for a low mainstream turbulence,but diminished for a high mainstream turbulence at the end-wall effect region.The influence of mainstream turbulence on the heat transfer coefficients vanished at the end-wall effect region.