Central Propellant Deflection Angle Model of Pintle Injector

In order to accurately predict the central propellant deflection angle of pintle injector, the theoretical model of central propellant deflection angle was established based on flow field analysis. A central propellant deflection angle formula was deduced from the momentum conservation equation, which was verified by numerical simulation and experimental results. Moreover, the effects of structure parameters and working parameters on the central propellant deflection angle were analyzed. The results show that the predicted values of the theoretical model are in good agreement with the numerical and experimental results. The injection area of sleeve shielding has the greatest influence on the deflection angle of the central propellant. In the case of variable thrust, the central deflection angle decreases as the injection area of sleeve shielding increases. Injection pressure drop, wall thickness and cavity depth at the bottom of central cylinder have little effect on central deflection angle. When the injection area of sleeve shielding is constant, the deflection angle with a cavity at bottom of the central cylinder is about 6° larger than that without a cavity. This model can provide an important reference for the engineering design and the further accurate calculation of spray angle at variable thrust of pintle injector. © 2021 Editorial Department of Journal of Propulsion Technology. All right reserved.