Study On The Structure Of Shock Reflection Induced By Separation Based On The Principle Of Minimum Entropy Production

The separation-induced shock wave reflection widely exists in the internal flow field of the hypersonic aircraft’s propulsion system.External factors can affect this kind of flow field easily,causing the flow parameters to change dramatically.And that will pose a threat to the performance of the propulsion system.Therefore,it is necessary to conduct a more detailed study of the separation-induced shock reflection structure.Firstly,the flow field of separation-induced shock wave reflection is divided into three sub-flowfields,and all these sub-flow-fields including shock reflection and the boundary layer are analyzed theoretically using the minimum entropy production principle,free interaction theory and inviscid shock wave theory.Then,two theoretical methods of solving separation shock angle are proposed.According to the methods,two theoretical solutions of the shock strength are obtained through numerical calculation.Account for the deference between the two theoretical solutions,it is considered that the two theoretical solutions actually represent the separation shock angles of different meanings.The combined effect of multiple factors causes the entire separation shock wave to bend.Furthermore,according to the relationship between the two theoretical solutions,different scales of separation region are also divided.Subsequently,a series of simulated flow fields are obtained by the CFD method,and the results are in good agreement with the solutions predicted by theoretical analysis,which can verify the reliability of minimum entropy production principle.Finally,the factors that may affect the flow field induced by separation are analyzed,and the results of CFD simulation are given to verify the influence of factors like the expansion fan angle,on the structure of the flow field.