Study On The Effect Of Flank Grooves And Oblique Wing On Engine Performance

The air rocket were non-guided munitions that equipped on fighter or helicopters,which powered by solid rocket engine.Taking an air rocket as the research object,this paper first calculates the internal ballistic of the engine and obtains the internal ballistic performance parameters of the engine at high,low and normal temperatures.Then the numerical simulation of the jet flow field of the air rocket launcher was carried out,and the influence of the nozzle vane slot and the inclined fin on the engine performance was obtained.Finally,through the unsteady calculation,the change of the guidance torque of the rocket launcher tube with time is obtained,and the muzzle velocity of the rocket launcher is obtained.Details were as follows:(1)With reasonable assumptions,the ballistic performance of the air rocket engine was calculated.By the fourth-order Runge-Kutta method,the internal ballistic equations of the engine are solved,and the internal ballistic performance of the engine under three working states of high,low and normal temperature is obtained.The accuracy of the interior ballistic calculation is verified by comparing with the static experimental data.(2)The physical model of air rocket is modeled and simulated by Fluent.The steady flow field of the engine nozzle under different working pressures is numerically simulated.The variation of the flow field and the nozzle jet flow under different working pressures is analyzed.Comparing the literature data before the calculation,the numerical calculation method was verified.The characteristic parameters such as the nozzle Mach number along the axis and the intersection angle of the shock wave inside the nozzle were lower than the experimental results in the literature to meet the demand.The correctness of the calculation results is verified by one-dimensional isentropic calculation.(3)The numerical simulation of the nozzle flow field and the nozzle flow field under the condition of ignoring the existence of the vane are carried out.The influence of the vane groove on the performance of the engine is obtained by comparing with the calculation results of the single nozzle.The research shows that the vane slot affects the integrity of the nozzle surface,which increases the axial flow velocity loss of the gas,resulting in the decrease of the nozzle outlet velocity and the thrust of the engine.(4)The numerical simulation of the nozzle flow field under the converging wing condition was carried out.The influence of different inlet pressure and wing inclination angle on the performance of the engine under the confined wing condition was analyzed.Rocket muzzle velocity at oblique angle.Research shows that the inlet pressure has little effect on the outlet velocity of the nozzle.The larger the inlet pressure,the greater the impact of the gas on the fins,the greater the torquing torque experienced by the rocket.The increase of the inclined angle of the fins will increase the steering torque of the rocket and the thrust of the engine and the outlet flow rate will remain basically unchanged.The greater the inclination of the fins,the larger the rocket muzzle velocity.