Study On The Mechanism Of Gas Jet Penetration And Mixing On Supersonic Flow At Different Jet Parameters

The scramjet engine is one of the most efficient engines for future aspirating hypersonic flight.However,due to the high inlet velocity of the combustion chamber,the airflow in the combustion chamber has a short residence time,so it is difficult to obtain stable and efficient combustion.The mixing of fuel and air molecules in the combustion chamber must be done within a limited length of the combustion chamber.The rapid mixing and combustion process that is almost simultaneously done in the combustion chambe.Based on the flow field simulation software of FLUENT,this paper systematically studies jet penetration depth and mixing characteristics for different injection angles,different Mach numbers and different jet exit shapes.The effect of the change of injection angle on the mixing efficiency,total pressure recovery coefficient and penetration depth is different: the larger the injection angle,the higher the mixing efficiency,and the lower the total pressure recovery coefficient;for the penetration depth,the injection angle It has the maximum penetration depth at 90°.Changing the Mach number of injection has little effect on the penetration depth of the jet,and only when the Mach number increases greatly,the penetration depth will increase significantly.With the increase of the injection Mach number,the jet is more likely to form a reverse vortex pair in the transverse section,which may improve the mixing characteristics of the jet.When only the shape of the injection hole is changed while ensuring other conditions,the elliptical,circular,and rhombic penetration depths are approximately the same,and the square is slightly larger.The total pressure loss square,the diamond shape is smaller than the ellipse and the circle.The mixing efficiency square and the diamond shape are larger than the circular shape and the elliptical shape..The dissertation selects the appropriate physical model and numerical method,and forms a complete numerical simulation method.Based on this,the distribution of flow field under different injection parameters is analyzed,and the mixing under various working conditions is quantitatively analyzed.The efficiency,total pressure recovery coefficient and penetration depth are summarized.The variation of various parameters on the mixing efficiency,total pressure recovery coefficient and penetration depth is summarized,which provides a theoretical basis for the fuel injection design of scramjet.