Effect of gas injection holes on mixing and combustion in solid propellant ducted rockets. (25th May 2023) - Zhang, Yiqiao
Highlights: A ground direct-connected experiment is carried out to verify the numerical method. Effects of the number and position of gas injection holes on combustion are studied. Number has more effect on combustion efficiency than position. The results of the study on the number of holes show that 5-hole has the best result. Less gas injected toward the exit of the air inlets leads to a better mixing effect. Abstract: Combustion efficiency is an important parameter of the combustion chamber. Gas injection holes have an important influence on the mixing and combustion in solid propellant ducted rockets, but there is currently little research on gas injection holes. This paper describes numerical simulations of solid propellant ducted rocket combustion chambers, with the numerical method verified through a direct-connected experiment. We investigate the effect of adding injection holes to the gas generator nozzle on the mixing and combustion performance, and examine the mixing degree, combustion efficiency, and flow field characteristics. This paper focuses on the number and the position of the gas injection holes. The results show that, when the total mass flow rate is constant, the mixing effect becomes better as the dispersion degree of gas injection increases and the mass flow rate of each hole decreases. For this study, the 5-hole scheme has the best performance, and when the total mass flow rate and the number of injection holes are fixed, a smaller mass flow rate of gas injected toward the outlet of each air inlet is more conducive to better mixing and combustion effects. When the total mass flow rate is constant and the shape of the injection holes are complete circles, increasing the number of holes is more effective than decreasing the mass flow rate of gas injected toward the outlet of the air inlets in improving combustion efficiency.