Study Of Nozzle And Plug Cooling Techniques With Supersonic Conditions

Based on the development of cooling technology with high efficiency and low resistance in the subsonic and supersonic mainstream conditions,the cooling technology of nozzle and plug is analyzed numerically,and the cooling structure under the supersonic mainstream condition is optimized.In this paper,the problems of flow and heat transfer in supersonic conditions and the cooling problems of rectangular nozzle and plug nozzle are studied.Firstly,the film cooling structure of the typical Rafael nozzle under subsonic,critical and supersonic main stream conditions is designed and the numerical study is carried out.The difference of film cooling characteristics between supersonic and subsonic mainstream conditions is preliminarily analyzed.It is found that the interference between film outflow and supersonic mainstream can be reduced and the cooling efficiency can be improved by optimizing the parameters of film hole.The cooling efficiency of the rear part of the nozzle expansion section is higher due to the mainstream expansion,which can be alleviated by optimizing the arrangement of film holes.At the same time,the research of plug cooling technology is carried out.In order to adapt to the complex aerodynamic characteristics of the alternating subsonic and supersonic zones on the plug wall,the idea of zonal cooling is established,and the impinging film cooling structure on the head and tail of the plug is optimized.The restraint and guidance of secondary flow are strengthened by the cooling structure.At the same time,give full play to the cooling potential of the cooling air.And the tail of the plug is further refined into zones,the optimized multi-oblique film cooling structure is introduced,which effectively reduces the surface temperature of the plug,and controls the plug temperature under long-term service temperature,and the wall temperature uniformity is improved.The structure of the outer wall of the plug at the tail edge of the support plate is optimized to reduce the influence of the support plate on the wall temperature distribution.Finally,based on the scaled plug model,the optimum design of multi-oblique hole film cooling structure is carried out.Under the condition of fixed density ratio,the influence of the geometrical parameters of the film hole on the wall heat transfer characteristics of the plug is obtained by numerical simulation.It is found that the cooling effect can be improved and the aerodynamic loss can be reduced by reducing the film hole angle and diameter of the hole.The research results lay a foundation for future scaled model experiments.