Flow field and heat transfer analysis in a MON/MMH bipropellant rocket engine

The development of mixed oxides of nitrogen/monomethylhydrazine (MON/MMH) small bipropellant rocket engines still mainly relies on a trial-and-error approach due to the fairly complex phenomena occurring inside the rocket engines. In order to support the design and optimization of small bipropellant rocket engines, simulation tools have been developed to predict thrust and heat load based on three-dimensional RANS simulations with a theoretical atomization model for the unlike doublet impinging jet that specify the particle velocity and size generated from the liquid sheet edge by the impinging jet. This paper outlines the modeling methods applied to approximate the physical phenomena in a bipropellant rocket chamber. Tool validation was performed based on the thrust and heat load of a 500N MON/MMH bipropellant rocket engine, which is the main thruster of the Japanese H-II Transfer Vehicle. Detailed three-dimensional flow and thermal characteristics in the thrust chamber were obtained. The interaction between the core and the film cooling flow was better understood as a result of this study. The simulation results regarding outer wall temperature distributions agreed well with the experimental data and reproduced the effect of the mixture ratio, which influences development of a thermal boundary layer and heat flux on the thrust chamber wall. The computed results clarified that a high mixture ratio induces high wall temperature in the MON/MMH bipropellant thrust chamber. © 2017 by Begell House, Inc.