Influence Of Injection Parameters On Performance Of Rectangular Supersonic Nozzle

Rectangular nozzle is conducive to flat body aircraft design and optimization,it can reduce aircraft supersonic drag and have excellent aerodynamic efficiency.Rectangular nozzle can enhance jet and outflow or jet turbulent flow mixing,reduce jet noise,and suppress the infrared radiation signature of hot jet.However,the vector control capability of rectangular nozzle is weak.If fluidic thrust vetoring applied to rectangular nozzle,it can change the thrust vector performance of rectangular nozzle effectively.Based on numerical simulation,the flow characteristics of rectangular supersonic nozzle was investigated,the flow characteristics and thrust performance of fluid thrust vectoring or shock vector control rectangular nozzle were investigated.The nozzle exit was a rectangle with an aspect ratio of 2.05.Performance analysis are conducted and basic conclusions are draw in terms of flow parameters(mainflow nozzle pressure ratio NPR,secondary pressure ratio SPR)and secondary injection geometric parameters(the injection position and angle,the slot length).The disseration is divided into five chapters as follows:In the first chapter,the research background is introduced,and then the progress of studies of rectangular nozzle and fluidic vector controlling nozzle.The principle of fluidic control and the analysis modle of fluidic vector controlling nozzle are introduced.An introduction of main research contents is following.In the second chapter,the design mothodolgy of nozzle is introduced,including the design of circular-to-rectangular convergence duct of supersonic nozzle and building the nozzle modle.The numerical methods employed are introduced and validated,indicating the engineering practical value of the numerical methods.In the third chapter,the effect of flow parameters on flow characteristics and thrust performance of nozzle is obtained.Off-design overexpanded rectangular nozzle flow was dominated by shock induced boundary layer separation.When fluidic thrust vetoring applied to rectangular nozzle,the secondary gas injection into the divergent of supersonic nozzle leads to shock intercation and separation zone upstream the inject slot,the shock/boudary layer interaction also generates a ? shock,the overpressure in the main je separation area induces an pressure force acting on the nozzle,generating a foce component on the direction oppsite to secondary jet.The unbalance pressure force and the secondary jet momentum produce the total side force and the desired thrust vector deflection.With the increase of main flow nozzle pressure ratio,main flow momentum increase,the effect of secondary injection on the main flow decreases,the pitch thrust vector angle and the pitch vector efficiency decrease.With the secondary pressure ratio is increased,secondary injection momentum increases,the effect of secondary injection on the main flow is intensified,the pitch angle increases and the pitch vector vector efficiency decreases.In the forth chapter,the effect of secondary injection geometric parameters on flow characteristics and thrust performance of nozzle is obtained under NPR=4.6.With secondary injection position move downstream,the position of shock move downstream and the strength is increased,but the affected area of secondary injection is decreased,the peak pitch thrust vector angle is at 0.605 jX l(28).With the secondary injection angle increases,the strength of shock increases,he peak pitch thrust vector angle is at ?=120°,and the pitch vector efficiency increases.With the slot length increses and the slot area unchanged,secondary injection momentum of per slot length decreases,but the affected area of secondary injection is increased,when the secondary pressure ratio is greater than 1,the pitch thrust vector angle increases with the slot length increased.