Investigation and Modelling of Coaxial Atomization in Liquid Rocket Engines.

Abstract

The mixing efficiency of injection is an important performance parameter in liquid rocket engines. Coaxial injectors have proven to be advantageous for the injection, atomization and mixing of propellants in cryogenic H2/O2 rocket engines. For these, a round liquid oxygen jet is atomized by a fast coaxial gaseous hydrogen jet.This paper briefly summarizes phenomenlogical studies of coaxial spray generation which based on the most important processes leading to atomization. These are indentified as turbulence in the liquid jet, surface instability, surface wave growth and droplet detachment.An attempt has been made to describe the main atomization processes using analytical and numerical methods. In the proposed atomization model, sub-models for primary break-up and droplet flow are solved in conjunction with the calculation of mean flow properties of gas and liquid flow. The model has been applied to several injection conditions and a comparison of simulation results and experimental data is described. The model limitations and possible extensions are also discussed.