An improved thermal jet for the propellant launching system

Abstract

This work is focused to study the energy release and flow behavior of liquid propellant during internal ballistics cycle of liquid launching system on the base of the thermal gas jet. Especially, an improved thermal jet is proposed via new type of stepped-wall chamber structure and thus the energy release efficiency is also enhanced with a decrease of pressure oscillation. The combustion of the liquid propellant in this system with a base ignition strongly depends on hydrodynamic instability of gas-liquid mixing process with high temperature and high pressure. The chamber structure has been verified to be as a means for controlling the instability problem in this propulsion process and three types of stepped-wall chambers are investigated to account for the effect of the stage on the flow and energy release behavior of liquid propellant based on this improved thermal jet. For the stepped-wall structure with three stages, the local liquid can be entrained into the Taylor cavity with more intense turbulent mixture at the corner of steps because of the existence of vortices under Taylor-Helmholtz effect. The corresponding propulsion efficiency γ only reaches to 1.003 mm−2 ms−1 and the muzzle velocity of the vehicle is 911 m/s with the maximum pressure of 317 MPa. Consequently, the heat transfer process from the high-temperature combustion-gas to the liquid propellant is also enhanced for the chamber with three stages, and more liquid propellant can be involved into the chemical reaction with providing more energy for the propulsion process of the launching system.