带肋壁与气膜孔内流通道中肋高度对流量系数的影响

Effect of Rib Height On the Discharge Coefficients of film Hole in the Internal Passage

在根据相似理论放大的模型上,测量了同时带肋壁与气膜孔内流通道中沿主流流向分布的各气膜孔的流量系数Cd。实验在内流通道进口雷诺数Re为20000～80000,通道总出流比SR为0 30～0 60,肋截面高宽比h/e为1 0和2 0以及肋角为60°的范围内进行,重点分析了肋高度对Cd的影响规律,并且进行了相应的数值模拟研究。结果显示:在低进口雷诺数Re(20000)和低通道总出流比SR(0 3),沿内流通道布置的各出流孔Cd通道前半部是上升的,在第五对孔时达到最大值,然后又沿通道而下降;在相同流动状况下,随肋高度的增大,肋所诱导的二次流强度增大,对带60°肋的通道而言,气膜孔流量系数降低。

Measurement of film hole discharge coefficients(Cd) in an internal passage with rib turbulators and film holes are presented.The internal passage is rectangular channel with two opposite ribbed wall,the aspect ratio is 1.0,and the rib turbulators are staggered arranged on the two wider walls.The cylindrical film holes are 45° inclined and perpendicular oriented,they are placed on one ribbed wall.Tests were run at rib orientation 60°,varying rib height-width ratio 1.0 to 2.0,Reynolds numbers (Re) changing from 20000 to 80000 and suction ratios (SR) changing from 0.30 to 0.60.Influences of rib tuburlators height on Cd are studied.Results indicate:1.At low Re(20000)and SR(0.3),Cd increase at first along the internal passage ,then decrease after the fifth pair holes;2.increasing rib turbulator's height lead to stronger secondary flows induced by ribs,thus lower Cd.