宽速域引射喷管巡航状态流动特性仿真

Numerical study on the flow characteristics of ejector nozzle with wide-speed range under cruise state

为了获得宽速域引射喷管在巡航状态下的流动特性,设计了工作范围为马赫数0~4的引射喷管,仿真分析了巡航状态4 Ma其内部的典型流动结构,并重点研究了引射系数(次主流流量比和总温比平方根的乘积)对引射喷管流动以及推力性能的影响规律。研究结果表明:巡航状态下,引射喷管内部的流动结构主要由主/次流剪切层、激波所组成,沿着激波方向,激波逐渐增强;引射喷管内部的剪切层存在“附壁”和“脱体”两种典型状态。随着引射系数的增加,剪切层从“附壁”状态切换至“脱体”状态,并且管内的激波强度呈现出逐渐减弱的趋势,推力系数呈现出先增加后降低的趋势。当引射系数在0.006~0.06时,引射喷管的推力系数可达到0.95以上。

To obtain the flow characteristics of an ejector nozzle under the cruise state,an ejector nozzle operating in the range of Mach number 0~4 is designed.The typical flow features under the 4 Ma cruise state are analyzed,and the effects of ejecting coefficient,which is defined as the product of the square root of total-temperature and the flow ratio between the secondary flow and the primary flow,on the flow structure as well as the thrust performance are studied emphatically.The results indicate that the main flow structure inside the ejector nozzle is mainly composed of the shock wave and the shear layer between the main flow and secondary flow under the cruise state.The shock gets intensified gradually along the shock direction.The shear layer inside the ejector nozzle has two typical states of“attached to the surface”and“detached from the surface”.As the ejecting coefficient increases,the shear layer transforms from the state of“attached to the surface”to the other one,and the shock strength in the tube shows a gradual weakening trend,while the thrust coefficient increases first and then decreases.When the ejecting coefficient is between 0.006 and 0.06,the thrust coefficient is higher than 0.95.