Investigation on turbulent mixing and combustion for air-turbo-rocket engine with turbine partial admission

In order to reveal turbulent mixing enhancement and chemical reaction mechanisms of the fuel-rich gas and airflow under turbine partial admission conditions in the combustion chamber of air-turbo-rocket engine, numerical simulations on turbulent mixing and combustion of the fuel-rich gas and airflow were carried out. A quantitative analysis was also conducted to study turbulent mixing and combustion efficiency of two kinds of mixing scheme by taking advantage of experimental results. Analysis results show that the convective mixing and streamwise vortices induced by a spanwise array of large scale secondary flows play dominant role in the introduction of lobed mixers to augment mixing of the bypass and core flows with a partial admission turbine. Partial admission flow conditions have significant effect on three dimensional distribution and the vorticity of initial vortices. Whether partial admission enhances turbulent mixing quality downstream of the lobe trailing edge or not rests with the lobed configuration. Furthermore, results indicate that hydrogen oxidation and ammonia free radical decomposition which involve a branched chain process are the main chemical reactions for fuel-rich hydrazinolysis gas. Thermal mixing efficiency is valuable reference quantity to estimate the turbulent combustion efficiency.