尾缘切除对低压涡轮叶栅气动性能的影响

The effect of trailing edge removal on the aerodynamic performance of low⁃pressure turbine cascade

选取某低压涡轮导向叶片中截面叶型作为研究对象,采用数值模拟方法研究尾缘切除对低压涡轮叶栅气动性能的影响,研究切除长度分别为2.5%、5.0%、7.5%弦长时叶栅气动性能的变化,并且采用尖边倒圆、将尾缘修整为圆弧形、椭圆形三种方式对切尾缘后叶型剩余尾部进行修型。结果表明:尾缘切除可有效增加叶栅槽道的流通能力,并且流通能力随尾缘切除长度增加而增加;切尾缘后叶栅损失增大,并且与尾缘切除长度呈正相关;切尾缘后的修型方式会对叶栅损失水平产生影响,将尾缘修整为椭圆形对损失抑制效果最明显,在同样切除长度下其尾迹损失和端区损失均低于另外两种修型方式;尾缘切除对叶栅出口气流角影响微弱,尾缘切除长度每增加1%弦长,三种修型方式叶栅出口气流角增加量为0.13°~0.16°。

Selecting the cross⁃sectional blade profile of a cer⁃tain low pressure turbine(LPT)guide blade as the research object,numerical simulation methods were used to study the effect of trailing edge cutting on the aerodynamic performance of low⁃pressure turbine cascades.The changes in the aerody⁃namic performance of the cascades were studied when the cut⁃ting lengths were 2.5%,5.0%,and 7.5%chord lengths re⁃spectively.The remaining tail of the blade profile after cutting the trailing edge was modified by using three methods as sharp edge rounding,trimming the trailing edge to a circular and el⁃liptical shape.The results show that trailing edge removal can effectively increase the flow capacity of blade cascade chan⁃nel,and the flow capacity increases with the length of trailing edge removal.After cutting the trailing edge,the blade loss increases and is positively correlated with the length of the trailing edge cut.The trimming method after trimming the trai⁃ling edge will have an impact on the level of blade cascade loss.Trimming the trailing edge to an elliptical shape has the most significant loss suppression effect.Under the same trim⁃ming length,the wake loss and end zone loss are lower than the other two trimming methods.The effect of trailing edge re⁃moval on the outlet airflow angle of the blade cascade is weak,and for every 1%increase in the chord length of trailing re⁃moval,the three modification methods increase the outlet air⁃flow angle of the blade cascade by 0.13°to 0.16°.