一种降低端壁温度的离散气膜孔布置

A Discrete Film-Hole Arrangement to Reduce Endwall Surface Temperature

本文利用端壁表面耦合传热温度分布作为设计依据,提出了一种可以降低端壁表面整体温度、强化前缘与压力面根部冷却效果的离散气膜孔布局。在主流温度T_∞=200℃和冷热气流质量流量比MFR=1.0%的工况下,实验比较了这种离散气膜孔布局与顺排布局对端壁冷却带来的影响,可以发现:1)二次流导致顺排气膜孔布局并不能获得均匀的端壁表面温度分布;2)在相同孔数下,对压力侧根部使用小径向角孔及孔加密,前缘吸力侧进行孔加密和使用对冲孔,以及其他区域均匀布孔,可以使端壁表面温度分布更加均匀、温降更大;3)较顺排布局而言,离散布局使得端壁吸力侧前缘和压力侧根部冷却效果分别提高了36.4%和32.7%,即使在最小温降区域,其冷却效果也提高了10%左右.

In this paper,a discrete film-hole arrangement,which can reduce the temperature at the entire surface and improve the cooling effect in the pressure side (PS)and the leading edge (LE)of suction side (SS)at a vane end-wall,was proposed based on the conjugate temperature.The comparison under the condition of the mainstream temperature T∞=200℃ and coolant-to-mainstream mass flow ratio MFR=1.0% revealed that:1)the complicated secondary flow results in a non-uniform temperature distribution at the end-wall with the tactic film-hole layout;2)under the same number of holes,the proposed discrete hole-layout can obtain the more uniform surface-temperature distribution and the larger temperature drop,through arrangements of the holes with the smaller radial angle and pitch in PS,the holes with the smaller pitch and the opposite flowing angles in LE of SS,and the uniform holes in the other region;and 3)comparing with the tactic film-hole layout,for the proposed hole-layout,the cooling effect at LE of SS and the root of PS can be respectively increased by 36.4% and 32.7%,even at the region with the smallest temperature drop,the cooling effect can still be improved by about 10%.