叶栅反推器几何进气角、压比对反推性能的影响

Effect of Blade Entrance Angle and Pressure Ratio on Cascade Thrust Reverser Performance

航空发动机叶栅反推器叶型参数与反推效率、流量系数之间的规律对于反推装置的设计具有重要意义。建立了外涵叶栅反推器的轴对称计算模型,给出了内涵计算域的有效处理方法。利用数值模拟手段研究了叶片几何进气角、外涵入口压比的变化对反推效率、流量系数等的影响规律,并将计算结果与可能得到的试验结果的数据点进行了比较。结果表明,计算结果与实验结果吻合。当β1γ小于30°时,随着几何进气角的增加,反推效率快速增加,流量系数则迅速下降;当30°<β1γ<55°时,反推效率和流量系数随压比的变化都有较大波动;当β1γ大于55°时,继续增大叶片几何进气角β1γ,流量系数和反推效率均大幅下降。反推效率随着压比的增大而降低。在较小几何进气角时,流量系数随压比增大而增大,在较大几何进气角时,流量系数随压比变化不大。

It is important to study the mechanism between the cascade blade profile parameters and the thrust reverser effectiveness. By the numerical methods,the efficient and reliable numerical axisymmetric models have been established, especially the inner core passage, the effect of blade entrance angle and fan nozzle pressure ratio on thrust reverser effectiveness and discharge coefficient is investigated, the calculated results and the available experimental data are compared. Results show that the calculated and the experimental results are identical. When blade entrance angle less than 30° ,the effectiveness increase quickly, but the discharge coefficient decrease rapidly. When blade entrance angle is in the middle of 30°and 55°,the effectiveness and the discharge coefficient have a large fluctuate as the entrance angle increases. When the entrance angle more than 55 °, continue to increase the entrance angle, the effectiveness and the discharge coefficient decrease rapidly at the same time. The thrust reverser effectiveness declines quickly. The thrust reverser efficiency declines as the increase of the pressure ratio. The discharge coefficient increases rapidly as the increase of the pressure ratio in the small blade entrance angle while change smoothly in the big blade entrance angle.