Effect of tangential swirl air inlet angle on the combustion efficiency of a hybrid powder-solid ramjet

Abstract A new ramjet configuration using powder and solid fuel as propellant is investigated, namely, hybrid powder-solid ramjet (HPSR). Boron particles were used as the powder in this study. In order to improve combustion efficiency of boron and simplify the engine structure, a tangential swirl air inlet is adopted on the HPSR. Ignition model based on the multi-layer oxide structure and Global reaction combustion model of boron particles, the Lagrangian particle trajectory model and the realizable k-e turbulence model were implemented to calculate three-dimensional two-phase flow and combustion in the HPSR with the different tangential air inlet angles (0°,5°, 10°, 15°, 20°, 25°). The effects of tangential air inlet angles on the ignition and combustion of boron were analyzed. The results show that when the tangential swirl air inlet angle is 10°, the combustion efficiency of boron particles and the total combustion efficiency of engine are the highest; the temperature distribution in the second combustion chamber is uniform, and the ignition distance of particles is small, for the HPSR configuration tested.