Research on the flow field characteristics of solid rocket motor work at high altitudes based on immersed boundary method

Abstract Due to the difficulty of using the body-fitted mesh method to deal with complex moving boundaries, this article proposes to use the immersed boundary method to handle the combustion surface regression generated by the propellant combustion. The effectiveness of the immersed boundary method is verified through simulation calculations of the working process of the rocket engines working at high altitudes, and the flow field characteristics are analysed. The research finds that the higher the flight altitude is, the larger the initial expansion angle of the gas jet, the radial boundary of the jet flow-field, and the length of the jet starting section are. The larger the flight Mach number is, the smaller the initial expansion angle, radial boundary, and length of the starting section of the gas jet are. However, the length of the jet transition section has increased, and the fully developed section of the jet has moved back.