Research On Drags Of Two-dimensional Hypersonic Inlet

When flight mach number is greater than2~3, ramjet becomes the inevitable choice forhypersonic vehicle. Studies have shown that the thrust produced by scramjet is limited, therefore, inorder to obtain sufficient thrust, its drag must be reduced. As inlet is an important component ofscramjet, and it is the primary drag part, studying the drag characteristics of inlet is important.In this paper, numerical simulation is used to analyze the friction drag coefficient and thepressure drag coefficient impacting on the single and folding wedge. Then, a two-dimensionalhypersonic inlet was designed, and effects on drags of inlet caused by blunted leading edge and lipwere investigated. As the radius of blunted leading edge and lip were increased due to aerodynamicheating and ablation in hypersonic flight, Variation of different kinds of inlet drags were studied.Secondly, in order to improve the matter that traditional blunting way could seriously reduce thetotal pressure recovery coefficient and flow rate coefficient, a detailed study, which adopting severaldifferent asymmetric blunting ways, was performed for aerodynamic performance. The study showsthat asymmetric blunting can improve the total pressure recovery coefficient and flow rate coefficientof hypersonic inlet, but inlet’s ability of anti-ablation declines.Then a detailed study on internal drags of wall cooling is performed by theoretical analyses andnumerical simulations. With incoming Ma of6, the effects of wall surface temperature, whichinfluencing internal friction drag, pressure drag of simple compression surface and two-dimensionalhypersonic inlet, are discussed and the distribution of drag is given.At last, the internal drags of inlet with different wall roughness are investigated. The ability ofFluent on predicting drag of inlet with wall roughness is verified. The variation of friction drags andthe pressure drags of inlet with different wall roughness are discussed under the conditions that theMach number of incoming flow is varied from4to6. It is discovered that changes in wall roughnessimpact the friction drag greatly and effects pressure drag changes slightly.