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 Guoping HUANG;Chao LI;Chen XIA;Qian LI

作者机构：College of Energy and Power EngineeringNanjing University of Aeronautics and AstronauticsNanjing 210016China 

出 版 物：《Chinese Journal of Aeronautics》 (中国航空学报（英文版）)

年 卷 期：2022年第35卷第4期

页      面：230-244页

核心收录：

学科分类：08[工学] 082502[工学-航空宇航推进理论与工程] 0825[工学-航空宇航科学与技术] 

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)。 

主　　题：Variable cycle engine Rear variable area bypass injector Bypass ratio adjustment Mixed exhaust Thermal mixing Spanwise vortex 

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 ■.