射流控制反推力装置流场数值研究

Numerical Study on Thrust Reverser Controlled with

关键词:  涡扇发动机  叶栅  反推力装置  数值模拟  二次流

Key words:  Turbofan engine  Cascade  Thrust reverser  Numerical simulation  Secondary jet

摘要:

针对涵道比为8的涡扇发动机无阻流门叶栅式反推装置，利用CFD技术，计算分析了二次射流孔的位置、角度、孔数以及流量对反推力性能和外涵通道内流场流动特征的影响。计算结果表明:外涵流体与二次射流相互作用后，在二次射流下游产生了一个主涡和副涡，阻碍外涵气体向下游流动；射流孔位置对涡扇发动机的影响不仅体现在反推力效率，而且影响上游风扇后的气体压力不均匀度和背压；二次流射流角度对反推力性能的影响在诸多影响因素中占主导地位，存在一个最佳射流角度；二次流质量流量增加，反推力效率呈增加趋势；二次流入射孔的个数关系到相邻入射气流在周向的覆盖程度，从而影响反推效率；二次流射流位置、角度以及流量对反推性能的影响是相互耦合的，在反推力装置设计时需要综合考虑三者间的相互影响；在研究参数范围内，最佳的射流孔位置范围L=110mm~150mm，最佳射流角度[α]在10°~20°范围内。

Abstract:

For the turbofan engine with bypass ratio 8，the CFD simulations were performed to analyze the effects of the position，inject angle，hole numbers and mass flow rate of the secondary jet flow on the performances of the blocker-less thrust reverser and flow characteristics of bypass flow. The numerical results show that the bypass flow interacts with the secondary jet flow to produce two vortexes located on the downstream of the secondary jet . The vortex block the passage of bypass flow and turn the flow direction of the bypass flow. The position of secondary flow relates to the thrust reverser efficiency and the pressure distribution on the outlet of the engine fan. The inject angle of the secondary flow has a dominant effect on thrust reverser performance. The jet angle is also a determining factor for the thrust reverser. The thrust reverser efficiency improves as the increase of the secondary jet flow rate. The numbers of the jet holes relate to the coverage area of the secondary flow circumferentially. The effects of jet hole position，angle and jet flow rate are connected to consider on the design of the block-less thrust reverser. In this paper，the jet hole position is recommend ranging from 110mm to 150mm，and the inject angle is between 10° to 20°.