Numerical Simulation Of Drag Reduction By Magnetic Fluid Opposing Jet In Hypersonic Vehicle

Supersonic vehicle refers to an aircraft flying at a speed above Mach5.Hypersonic vehicle is of great significance to civil and national defense security,and it is also an important index to judge a country’s military and aerospace strength.Because of its absolute superiority in speed,hypersonic vehicle has a broad development prospect in the civil and national defense.Many countries in the world are developing hypersonic vehicle technology,among which drag reduction and thermal protection are two important problems need to be solved.The heat generated by friction with incoming streams during flight of a hypersonic vehicle can lead to complex physical phenomena,the most obvious of which is the thermal ionization.This phenomenon enables the fluid around the aircraft have certain electrical conductivity.Using this characteristic to control the flow field to reduce the resistance has become a research hotspot.In this paper,the finite volume method is applied to simulate the flow field of blunt body in hypersonic flight by solving the n-s equation and coupling the magnetofluid equation.According to the results,the drag reduction effect of the backward jet charged particles coupled with magnetic field interference and electric field is analyzed.In this paper,the interaction between the dipole magnetic field with different intensity and charged fluid from incoming flow is studied,and the structure of flow field,state parameters on stagnation point and resistance changes on blunt surface are analyzed.The results show that with the increase of the magnetic field strength,the distance of shock wave detachment increases within a certain range,the shock wave widens gradually on both sides of the blunt body,the drag coefficient decreases,and the pressure between the shock wave layer and the blunt body decreases.Secondly,the influence of different injection pressure ratios on the flow field under the same magnetic field is studied.The results show that with the increase of spray pressure ratio,the distance of shock wave detachment increases,and the surface pressure and temperature of blunt body decrease gradually.In addition,the pressure peak position on the blunt body surface changes.The interaction between dipole magnetic field and charged fluid is also studied under different Mach number conditions.The structural changes of flow field and surface pressure of blunt body under the interaction of magnetic field and charged fluid at different inlet Mach Numbers are analyzed.In addition,the changes of shock wave detach distance and resistance coefficient are analyzed.It is found that when the inlet Mach number increases,thedistance of shock wave detachment decreases,the surface pressure of the blunt body gradually increases,and the drag coefficient increases.By establishing a calculation model under the action of a uniform magnetic field,the flow field structure under the uniform magnetic field was simulated,and the variation law of the shock separation distance and the drag coefficient was analyzed.The calculation results show that the uniform magnetic field can change the structure of the flow field;when the magnetic field is added,the distance of shock wave separation increases with the increase of the magnetic field strength,and the resistance coefficient gradually decreases with the increase of the magnetic field strength.