Numerical Simulation Of Scramjet Inlet/isolator

The development of Hypersonic vehicle has been pushed to a new climax.Hypersonic inlet/isolator supplies high quality air flow for supersonic ramjetcombustion chamber and plays a key role in the achievement of the Hypersonic flight.Its performance directly affects the combustion in the combustion chamber.This article describes the numerical simulation method. The used numericalcalculation methods and software of the in this article are given. We choose theFLUENT software. And using the finite volume method, implicit second-orderupwind format and density based solver, using AUSM+format. Laminar flow viscouscoefficient adopt the Sutherland formula, turbulence model adopts theSpalart-Allmaras(S-A) model. This paper also describes the numerical calculationprocess. Pre-treatment uses the GAMBIT software for geometric modeling andmeshing. FLUENT is used to numerical calculation and after-treatment and the resultsoutput.In this paper, the flow field in the inlet and isolator under different airflowcondition are investigated. The flow field and performance index of the inlet andisolator of two levels of conical compression on non-uniform airflow are obtained.The influence and improved method of the inlet and isolator are analyzed. At first thecomputerized data are compared with Experiment data from NASA. The resultsshows that the calculation procedures used in this paper is applicable to supersonicinlet/isolator flow. Numerical simulation`s result shows that the total pressurerecovery coefficient is decreased on high Mach and non-uniform airflow. The resultsof numerical simulation shows that the performance of ramjet inlet is reduced byincreasing of Mach number. The shock rebound angle and the isolator entranceboundary layer separation are increased. Distortion index of the exit of the isolator isincreased. The total pressure recovery coefficient is decreased by non-uniform flow.The distortion of isolator exports was increased. It causes great impact to theperformance of scramjet inlet and isolation.In this paper, adjusted the isolated section of the up and down the wall at theentrance and through numerical simulation the law of the change of the improvementof inlet performance parameters are obtained. The improved model B is obtained. Theresults shows that the flow field of improved inlet/isolated is more stable onnon-uniform flow field and has a stronger anti-disturbance ability. Although the export total pressure distortion index and Mach number ofinlet/isolator have a little change. The total pressure recovery coefficient is increased13%.The performance of the inlet is improved. The thrust of the engine is increasedand the fuel consumption is decreased. At last this article calculates and analyzes theflow field on different attack angle. The result shows that Model B has a betteradaptability of attack angle.