Simulation Of The Aerodynamic Parameters Of Counterflow Thrust Vectoring Nozzle

Counterflow thrust vectoring, based on fluidic techniques, employs a secondarycounterflow stream to develop deflection of the main stream which will result inthrust vectoring. Compared to mechanical control thrust vectoring nozzle, it has amore simple structure, lighter quality and lower thrust loss, and also has obviousadvantages in reliability and stealth。This paper studied the aerodynamic parametersand the flow field’s structure of the counterflow thrust vectoring, the impact ofexternal flow on the performance of counterflow thrust vectoring nozzle, and theaerodynamic parameters and the flow field’s structure in unsteady situation.The aerodynamic parameters and structure of the internal flow field of thetwo-dimensional counterflow thrust vectoring nozzle under the impact of the externalflow were studied by numerical simulation. The results show that, the vectoring anglewill decrease as the Mach number of the external flow increases, when the Machnumber is less than0.7. But when the Mach is higher than0.7, the vectoring anglewill stop from decreasing. And the mass flux ratio of secondary flow will increase inforward flow direction as the Mach number increases. When the angle of the externalflow increase in positive way, the vectoring angle will increase and the mass flux ratioof secondary flow will increase in forward flow direction. When it increases innegative way, the vectoring angle will increase in backward flow direction.The aerodynamic parameters and structure of the internal flow field of themulti-axis diamond counterflow thrust vectoring nozzle, the impact of the externalflow, and the achieve of three-dimensional deflection angle were studied by numericalsimulation. The results show that, the largest deflection angle(24°) can be achievedwhen the secondary mass flow rates less than0.01and the thrust rate is bigger than0.92. When the Mach number of the external flow increases, vectoring angle and themass flux ratio of secondary flow will increase, and the thrust rate will decrease.When the angle of the external flow increase in both positive and negative way, thevectoring angle will increase and the thrust rate will decrease. When two suction gapswork together, a three-dimensional deflection angle can achieve, which is a littlebigger than that with one suction gap working.The aerodynamic parameters and structure of the internal flow field of the two-dimensional counterflow thrust vectoring nozzle under the unsteady situationwere studied by simulation. The result shows that, when φp=0.26、0.41、0.54, thechange of the boundary conditions will change the flow field and aerodynamicparameters, but they will eventually become stable. When φp>0.63, the flow field andaerodynamic parameters can’t become stable after the change of the boundaryconditions, instead they will present great unsteady volatility shocks.