Tail Flame Impact Characteristics And Launcher Structure Optimization Design For Thermal Launch At Sea

With the advantages of flexible launch point selection,safe landing area,lower launch and operation costs,the sea rocket launch technology can extremely well adapt to the launch needs of small satellite constellations from different angles,effectively use civilian ships,ports,measurement and control resources,realize the effective combination of space technology and marine engineering,and promote the development of commercial spaceflight in China.Compared with cold launch,the system is highly versatile,simple in structure and improves the launch efficiency of rocket during hot launch,however,during the rocket launch,the high-speed,high-temperature and highpressure gas jet ejected generates a large amount of heat energy,which generates a large impact load and heat load on the surface of the launcher,directly affecting the structural stability and safety of the launcher.Therefore,the study of gas jet characteristics during the thermal launch of offshore rockets,through the analysis of the jet pressure loading mechanism of the launcher,improves the rocket thermal launch technology,provides technical support for the structural safety design of the launcher,and is of great significance to boost the rapid development of commercial spaceflight.In this paper,we firstly take a certain type of sea rocket thermal launcher as the object of study,establish a symmetric model of 1/2 gas jet calculation domain,and investigate the impact characteristics between the gas jet and the launcher using theoretical analysis and numerical simulation methods,and on this basis,carry out thermal protection and structural optimization design of the launcher,the main work is as follows.(1)According to the solid device for the thermal launch of the offshore rocket,a three-dimensional fluid domain model of the single-nozzle launch vehicle engine is established by CATIA software,and the k-ω shear stress transfer(SST)turbulence model based on Reynolds averaging method in density basis is adopted in the FLUENT software of fluid dynamics through the basic assumption of ideal gas,and the flux difference discrete splitting(FDS)The results show that: with the increase of rocket flight distance,the jet appears to oscillate and decay continuously,and the jet impacts the deck at 1.092de(de is the nozzle exit diameter size)with a velocity of about 2400m/s,and the jet generates a concentrated high temperature of 3300 K in the deck stagnation zone,when the pressure changes most drastically to 1.8 When the distance exceeds 5de,the temperature of the rocket wake drops rapidly,and the speed and pressure distribution pattern along the nozzle axis is basically the same.30 de,the deck recovers the ambient pressure,the temperature is about 1500 K,the jet impact deck speed is about 500m/s,and the effective impact range is 2m.(2)The flow field simulation of the rocket belt launcher explores the effect of jet flow on the wall of three launchers under different launch heights and offset conditions,the extreme value curves of pressure measurement points of 17 cross-sections of the deflector are extracted,and the optimal launcher configuration is selected,c model increases the distance from the nozzle outlet of the first stage engine to the ridge of the deflector,and the environment of the launching platform is obviously improved,and the environment of the outrigger leg is also greatly improved,which is more favorable for the use of the rocket during multiple hot launches,extend the life of the launcher.(3)Finite element modeling of the launcher jet impact area using ABAQUS finite element analysis software.Through the input of boundary conditions,the p-r fitting equation of the applied pressure with the radial distance of the deflector,and the division of the structural mesh,the mechanical response of the launcher structure was obtained.The results show that the yield strength of the C model is less than the allowable stress value and the strain variation is smaller,and the structural strength meets the launch requirements and stability requirements,and there is a certain optimization margin.(4)Based on the temperature distribution characteristics and structural mechanical response of the launcher under the action of the jet,the thermal protection design and structural optimization design of the launcher were carried out.