加力燃烧室双层壁隔热屏综合冷却效率的实验研究

In order to study the cooling characteristics of the afterburner double-wall heat shield, the overall cooling effectiveness was modeled and the key parameters were matched. The overall cooling effectiveness distribution on the mainstream side of the film plate was measured by using IR thermography. Effects of opening rates of the impingement plate (φ=0.5%, 0.6%, 0.7%, 0.8%) and momentum flux ratios (I=0.02~1.38) on the cooling characteristics were investigated experimentally. The results indicate that the deviation of the overall cooling effectiveness between laboratory conditions (the temperature ratio of mainstream flow to secondary flow T_g/T_c=2) and engine conditions (T_g/T_c=4) is within 0.054. Along the mainstream direction, the overall cooling effectiveness on the mainstream side of the film plate fluctuates and increases. As the momentum flux ratio increases, the overall cooling effectiveness near the impingement stagnation point increases.The shape of the film cover in the middle and downstream region of the film plate gradually disappeared, and the overall cooling effectiveness of upstream region of the film plate increased the most. With the increase of the opening rate, the arrangement of impingement holes and film holes becomes denser, the impingement heat transfer and the film superimposition effect are enhanced, so that when the opening rate increases from 0.5% to 0.8%, the area averaged overall cooling effectiveness increases 21.2%, and the mixing of the mainstream flow and the secondary flow enhances the heat transfer on the mainstream side of the film plate, which leads to a decrease of the overall cooling effectiveness growth rate.