Investigations of entrainment characteristics and shear-layer vortices evolution in an axisymmetric rear variable area bypass injector  

作　　者：Guoping HUANG Chao LI Chen XIA Qian LI 

机构地区：[1]College of Energy and Power Engineering,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China

出　　处：《Chinese Journal of Aeronautics》2022年第4期230-244,共15页中国航空学报（英文版）

基　　金：supported by National Major Science and Technology Projects of China(J2019-Ⅱ-0007-0027);Fundamental Research Funds for the Central Universities,China(3082018NP2018102);National Natural Science Foundation of China(12002162);Jiangsu Province Natural Science Foundation,China(BK20200449)。

摘　　要：In this study,firstly,for the axisymmetric RVABI,the change-rule of adverse pressure gradient caused by radial velocity during the transition of internal flow mode in variable geometry is summarized,and a Bypass Ratio(BR) iterative algorithm based on the empirical correlation of non-equilibrium pressure is proposed.The algorithm can estimate the nonlinear relationship between area ratio and BR,with an error range falling below 6.5%.Then,we discuss the favorable effect of uniform mixing on the thrust augmentation of mixed exhaust under variable BR conditions.From this point of view,the characteristics of vortices evolution in different shear strength jets are compared,to clarify the effect of variable cycle parameters on jet mixing.As the results suggest,when ■ is as low as 0.22,the K-H disturbance is of high-frequency wavelet property,and it is difficult to induce large-scale spanwise vortices.The macro migrations of fluid elements in span wise vortices and the diffusion effect caused by edge tearing is weak,which is not conducive to the energy exchange between the two streams.However,the low ■ jet will also correspondingly weaken the viscous dissipation effect of vortices.It is concluded that the dissipation level is proportional to the 2.31 power of the ■.

关 键 词：Variable cycle engine Rear variable area bypass injector Bypass ratio adjustment Mixed exhaust Thermal mixing Spanwise vortex 

分 类 号：V23[航空宇航科学与技术—航空宇航推进理论与工程]