扇形与平面叶栅内高负荷叶片的换热特性实验研究

To explore the overall heat transfer characteristics of highly-loaded blades with sector cascade and linear cascade，the effects of Reynolds numbers（Re）and turbulence intensity（Tu）on the Nusselt number （Nu）of highly-loaded blades with small aspect ratio were measured by using the transient liquid crystal measurement technique with a sector cascade（curved endwall）. The results were compared with those of a linear cascade （straight endwall）. The results reveal the asymmetric distribution of heat transfer along the blade height of the curved endwall. That is because the radial inlet angle increases by 21.5° of curved endwall compared with straight endwall and the upper and lower endwalls have different curvature of curved endwall. With the increase of Re，the heat transfer at each position of the blade is obviously enhanced，and the transition point of the laminar boundary layer on the suction surface is approaching to the leading edge. The effects of Re on straight endwall are greater than those on curved endwall. With the increase of Tu，the overall Nusselt number（Nu）increases. The transition point on the suction surface moves forward，and the transition phenomenon on the pressure surface is obviously enhanced. The one-dimensional characteristic of Nu on the middle chord is more obvious. Tu has similar effects on the blades of two endwalls. In the study of the influence of low Re or Tu on the heat transfer of highly-loaded blades，the straight endwall can be used for simplification. But in order to ensure the accuracy of high Re，the experiment should be carried out in the real sector cascade of the engine.