地外天体起飞羽流导流气动力效应仿真

During the return progress of the detector from the extraterrestrial celestial body after sampling, the ascent engine plume flows back to the ascender after the reflection from the launching pad upper surface, which causes aerodynamic effect and disturbing torque effect on the ascender. Numerical simulations have been done with the computational fluid dynamics and direct simulation Monte Carlo (CFD/DSMC) coupling method to analyze the plume aerodynamic effect during the takeoff. The influences of takeoff distance of 200-700 mm and deflection angle from 0° to 5° of ascender on plume aerodynamic effects have been considered in this paper. It has been found that with the increase of takeoff distance and deflection angle, the torque of the ascendere has been changed from positive to reverse, which seriously affects the takeoff stability. The reason of this phenomenon is considered to be that, when deflection angle increases, the impact point between the plume on the further side of the ascender from the launching pad and the launching pad has moved from the cone flame deflection to the plane. This phenomenon causes plume flow direction to change suddenly from close to the launching pad and flow to the side to rebound from the launching pad and flow to the bottom of the ascender. Eventually, the side of the ascender far from the launching pad is subjected to a higher torque than the side closer to the launching pad, and a reverse torque is generated.