Hui Wang
N–S equation, direct simulation Monte Carlo, vacuum plumecnumerical simulation
A large number of aircraft need to be launched in space engineering, but the gas plume jetted by the engine which provides power in the weightless vacuum environment of space will expand rapidly and affect the aircraft. In this study, the N–S equation used for simulating continuous flow and the direct simulation Monte Carlo (DSMC) method used for simulating rarefied gas were briefly introduced first. Then after coupling the two methods, the vacuum plume of an engine was simulated by ABAQUS software. The distribution law of the vacuum plume was analysed. Moreover, the simulation results were compared with the numerical simulation results of the DSMC method and the actual results of model test. The results showed that the vacuum plume of an engine could be divided into continuous zone, transition zone and free distribution zone according to Kn, in which the transition zone is generally elliptical, and the transition zone of the DSMC simulation was larger. Then according to the distribution law of the pressure, Kn, temperature and Mach in the X-axis direction and exit section of the engine nozzle and the speed in the X and Y directions, it was found that the distribution tendency of the two methods was basically consistent, i.e., the vacuum plume of engine suddenly swelled after leaving the exit, the swelling became slower with the increase of the distance, and a reverse speed region generated around the exit, affecting the stability of the aircraft. But compared to the actual data, the coupling algorithm proposed in this study was more close to the actual result. In conclusion, the numerical simulation algorithm of the DSMC method coupled with N–S equation can effectively simulate vacuum plume, which can provide an effective support for the motion law of vacuum plume and a data reference for the design of space craft nozzle.
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