Experimental investigation on hot water rocket engine

In order to understand the internal ballistic performance of the hot water rocket engine, the experiment was performed in different initial pressure, different spray pipe diameter and different water added. Through the experiment, the working data of the engine under different conditions were obtained. Through the analysis of the data, four working stages of the engine were put forward, which were initial segment, transition segment, approximately linear segment and a trailing segment, respectively. The influence law of the initial pressure, nozzle diameter, the amount of water added on the internal ballistic performance of the engine were obtained. Meanwhile, it has been found that in the engine working process, the pressure curves experience a sharp decline first and then slow drop, but when the initial pressure is lower, the pressure curve in the transition period would experience a short rise first then decrease fluctuation. And it is observed that the specific impulse of the hot water rocket engine is greatly influenced by initial pressure, but has nothing to do with spray pipe diameter or water added and the thrust calculation formula of the conventional rocket engine is not suitable for hot water rocket engine.