Research on ignition matching for magnesium-based water ramjet engines

This paper addresses the ignition compatibility issues of the water ramjet engine (WRE). It studies the impact of several engine parameters on the ignition process and performance, including the primary water injection angle, primary water-fuel ratio, igniter mass, and igniter position. Based on the specified parameters, a multiphase flow computational model for the ignition process of the WRE developed. The obtained results show that the ignition performance of the engine is significantly affected by the primary water-fuel ratio, igniter mass, and igniter location. When the primary water-fuel ratio increases, the equilibrium temperature in the combustion chamber tends to initially increase and then decrease, reaching a maximum value for a ratio of 0.55. Criteria are then proposed to determine whether the WRE can transition into the self-sustained combustion phase. These ignition criteria are established by considering the relationship between the mass of the igniter charge, its location, and the surface area of the burning surface of the propellant. The results obtained by the proposed model demonstrate that the engine will not extinguish when this value is greater than 46.65.