Numerical simulation of unsteady working process of hot water rocket motorr

In order to understand the working performance in the hot water rocket motor better, a numerical model of the flow field of hot water rocket motor was established and then the unsteady working process was simulated. And the numerical model was validated via comparing with the experimental data. According to the study of the working process of the motor, it is found out that in the working process, phase change process is slow in the main body while it is severe in the nozzle, so the gradient of vapor volume fraction in the nozzle is larger. The closer to the nozzle exit, the greater the vapor volume fraction, vapor volume fraction at the exit is above 90%, and the lower the temperature. The pressure in the motor firstly drops to the saturated pressure corresponding to the initial temperature and then decreases slowly. And the working process are divided into three stages, which are initial segment, middle segment, and a trailing segment. Total impulse of the motor is mainly concentrated in the middle segment, which is about 70% above of total impulse.