Abstract: 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. 

Key words: Hot water rocket engine；Internal ballistic performance；Experimental investigation

摘要： 为了解热水火箭发动机的内弹道性能,分别在不同初始压强、不同喷喉直径、不同加水量的情况下进行了实验。获得了不同情况下发动机工作的数据。通过数据的分析,总结提出了发动机工作的四个阶段:初始段、过渡段、近似线性段和拖尾段；得出初始压强、喷喉直径、加水量对发动机内弹道性能的影响规律,同时发现了在发动机工作工程中,其压强曲线都是经历一个先急剧下降后缓慢下降的过程,但是当初始压强较低时,压强曲线在过渡段会出现一个短暂的先升后降的波动。分析得出:热水火箭发动机的比冲受初始压强值的影响较大,而与喷喉直径或者加水质量无关；常规火箭发动机的推力计算公式并不适用于热水火箭发动机。 

关键词: 热水火箭发动机;内弹道性能;实验研究 