结构参数和涵道比对新型漏斗/环形组合式混合扩压器性能影响的数值研究

Numerical Investigation of Effects of Geometrical Parameters and Bypass Ratio on Performance of a Funnel/Ring Hybrid Mixing Diffuser

关键词:  组合式混合扩压器  漏斗高度  进气冲角  进气节角  涵道比

Key words:  Hybrid mixing diffuser  Funnel height  Inlet attack angle  Inlet throttle angle  Bypass ratio

摘要:

为了提高航空发动机加力燃烧室总体性能，提出了一种新型漏斗/环形组合式混合扩压器。采用数值模拟方法研究了结构参数和涵道比对该组合式混合扩压器流动和混合性能的影响规律。结构参数包括漏斗高度、进气冲角、进气节角。结果表明：组合式混合扩压器下游呈现剪切与涡流同时存在的流动和掺混特征。漏斗下游会形成一对旋向相反的流向涡对，支板下游形成剪切层。漏斗高度对组合式混合扩压器性能影响较大，其值越大热混合效率越高，同时总压损失也越大。组合式混合扩压器初始热混合效率随着进气冲角和进气节角增大而升高，混合充分发展后热混合效率相差不大，总压损失随着进气冲角的增大而增大，随着进气节角的变化差别不大。热混合效率随着涵道比增大逐渐降低，当涵道比大于0.8时基本保持不变。

Abstract:

The idea of a novel funnel/ring hybrid mixing diffuser is proposed to improve the performance of aero-engine afterburner. The effects of geometrical parameters and bypass ratio on the flow and mixing performance of the mixing diffuser are investigated by numerical methods. The geometrical parameters include funnel height， inlet attack angle and inlet throttle angle. The results show that a counter-rotating vortex pair is formed near the funnel exit， shear layer is formed near the ring exit， therefore， the hybrid mixing diffuser downstream flow features both vortical mixing and shear mixing. Funnel height shows a significant influence on the performance of the hybrid mixing diffuser. Both the thermal mixing efficiency and total pressure loss increase as the funnel height increases. The initial thermal mixing efficiency increases with the increase of the inlet attack angle and inlet throttle angle. After the mixing is fully developed， the thermal mixing efficiency varies little as the inlet attack angle and inlet throttle angle variations. The total pressure loss increases with the increase of inlet attack angle and keeps nearly constant with changes of inlet throttle angle. The thermal mixing efficiency decreases with the increase of bypass ratio， and remains unchanged when bypass ratio is more than 0.8.