Reconstruction Of Supersonic Flowfield And Investigation On The Drag Reduction And Thermal Protection Properties Of The Porous Opposing Jet

Compared with traditional vehicle,the hypersonic vehicle has the advantages of fast flight speed,short response time and strong penetration ability.Its huge economic benefits and military value make it become one of the most potential technologies in the field of civil and military applications in the future.Generally,the efficiency and performance of the vehicle depend on the physical characteristics of the flow field of the vehicle or the propulsion system.The supersonic/hypersonic flow field is characterized by a strong shock wave system,and the shock wave intensity increases gradually with the increase of the Mach number.The vehicle will suffer from the huge aerodynamic drag and thermal,and its performance will decline sharply.Therefore,reducing the aerodynamic drag of hypersonic vehicle head and improving the aerodynamic thermal phenomenon become the key issues in the development of hypersonic technology.In order to improve the drag reduction and thermal protection performance on the head of the hypersonic vehicle,in this analysis,the three-dimensional compressible Reynolds Averaged Navier-Stokes(RANS)equations coupled with the SST k-ωturbulence model are used to perform the numerical simulation in the flow.The reliability of the numerical approaches is verified by comparing with the available experimental data from the published literature.Parametric investigation on drag reduction and thermal protection characteristics of the porous opposing jet is studied.The flow field characteristics of the diameter,the spacing and the number of jet orifices are compared and analyzed.The obtained results show that the porous opposing jet can play a good role in both drag reduction and thermal protection.Changing the parameters of the porous opposing jet has a great impact on the drag reduction and thermal protection of the hypersonic vehicle,and the effect on the thermal protection is more obvious than that on the drag reduction.It is found that when the number of jet orifices is odd,the influence of drag reduction and thermal protection is better than that when the number of jet orifices is even.It is further found that in the study of the influencing factors of the porous opposing jet on drag reduction and thermal protection have shown that an important performance of the drag reduction variation and thermal protection effect caused by structural parameters is the variation of mass flow rate.Therefore,this paper takes the mass flow rate of the porous opposing jet as the main influencing parameter,and discusses the influence of the variation of different structural parameters on the drag reduction and thermal protection effect with the constant mass flow rate through numerical study.The obtained results show that the flow field pattern similar to the long penetration mode(LPM)in the single orifice opposing jet appears with the variation of the PR value.With the constant mass flow rate,the minimum value of the drag coefficient all appears in the transition stage from LPM to SPM,and the wall areas are all in the environment of low temperature by adjusting the structural parameters,which is the desired effect of the thermal protection.Finally,the effect of the porous opposing jet configuration on the aerodynamic performance of the blunted waverider vehicle is studied,and the heat flux peak can be further reduced by adjusting the distribution of the PR value.At the same time,the effect of different angle of attack and side slip on drag reduction and thermal protection is analyzed.The results show that the aerodynamic performance of the blunted waverider vehicle can be effectively improved by adding the porous opposing jet configuration,and the flight attitude with small angle of attack is beneficial to the lift-drag ratio of the blunted waverider vehicle.