Study on breakup length of liquid jet by liquid-gas coaxial injector - Evaluation of atomization characteristics of rocket engine injectors

Abstract

Based on the experimental observations using a liquid-gas coaxial injector with fairly dense liquid injection, an empirical calculation model of the breakup length of a liquid jet was derived. It is based on the one-dimensional momentum conservation equation for two-phase flow, as well as on the critical Eötvös number, which was derived experimentally by the author in a previous study. This model was applied to evaluate the local stripping rate of the liquid mass at the interaction surface between a liquid and a gas, and was applied to calculate the size of the formed droplets. Comparisons of the mean droplet size, distribution histogram of the size, and breakup length of the liquid jet were made with experimental data. This calculation model was also applied to evaluate the characteristics of the rocket injectors chosen as candidates for the LE-5, the liquid oxygen/hydrogen engine of the second stage of the Japanese H-1 launcher. © 2006 The Japan Society for Aeronautical and Space Sciences.