Study On Base Thermal Environment Of Vertical Round-trip Rocket Considering Afterburning

With the increase of space launch missions and the intensification of space market competition,the development of reusable rockets has become an urgent choice for large space powers.At present,many tests have been carried out on the vertically returned rockets by the United States,and the vertical landing on land and at sea has been successfully realized.Great breakthroughs have been made in the reuse of rockets.With the increasing number of space launch missions in China,the demand for autonomous reusable launch vehicles will become more urgent.However,there is no relevant content about the test or numerical calculation of reusable launch vehicles in China from published articles.In this case,the numerical calculation of the base thermal environment of a full flight for a new type of liquid rocket was carried out.Based on the existing theory,the CFD method,combined with HITRAN database and the ray tracing method,was used to establish the corresponding flow field,afterburning and thermal radiation calculation models for each stage of the rising and returning process of a new type of liquid rocket.In our country,we took the lead in the numerical calculation of the base thermal environment of the first-stage rocket during the whole flight,especially during the various stages of the rocket's return process,and verify the correctness of the flow field calculation model and the radiation model respectively.Then,in view of the serious scouring of the bottom of the rocket body caused by the reverse jet during the second ignition stage of the rocket return process,the effect of the afterburning on the base thermal environment of the liquid rocket's return stage was first considered in China.By comparing the spectral radiation characteristics calculated in this paper with the experimental data in the literature,it shows that the calculation model and algorithm in this paper are credible.The results show that the maximum convective heat flux is 18.57kw/m~2 and the maximum radiative heat flux is 42.101 kw/m~2 in the base thermal environment of the rocket during the rocket ascending stage.During the rocket return process,the maximum convective heat flux and radiative heat flux are 411.589 kw/m~2 and 49.749 kw/m~2,respectively.The maximum convective heat flux on the landing legs is 105.712 kw/m~2 and the maximum radiative heat flux is 39.149 kw/m~2.Through the analysis of the flow field contour and the heat flow environment of each measuring point during the return process,it is found that the rocket jet directly washes the rocket at the altitude of 22.262 km-33.04 km,which has the most severe impact on the rocket.Therefore,considering the effect of the afterburning reaction at the altitude of 29.009 km,it is found that the afterburning reaction is the most intense at the altitude of 29.009 km,and the afterburning reaction has the greatest impact on the bottom,side wall and landing branch of the rocket.The convection and radiation heat flux of legs increased greatly,up to 80%.In addition,when the rocket returns,the effect of afterburning on convective heat flux is much greater than that of thermal radiation,which is different from the trend calculated in literature.The models,codes and results presented in this paper can be applied to the differential fine thermal design of the bottom of a repeatable liquid rocket.