Combustion and detonation of paste fuel of rocket engine

Abstract

Purpose. Confirmation of the possibility of using a paste fuel based on ammonium perchlorate in a rocket engine and identifying the characteristics of its combustion. Methodology. Previous experimental studies on the burning of paste fuel in a constant pressure bomb determined the burning rate at different pressures. The stability of deflagration combustion without transition to the detonation mode was confirmed. An explosion occurred during the fire test of the engine model on paste-like fuel. The analysis of the causes of the explosion made it possible to put forward a hypothesis about the enrichment of the paste fuel with ammonium perchlorate, which created the prerequisites for its detonation. The conducted additional experiments showed a change in the combustion mode when enriching paste fuel with ammonium perchlorate. Findings. Theoretical and experimental studies have shown the possibility of obtaining detonation fuel based on the enrichment of paste fuel with ammonium perchlorate. It has been proven that, under certain production conditions, paste fuels can detonate, which opens up a new way of using such fuels for rocket engines. The conditions for the transition of the burning mode of pasty fuel from deflagration to detonation combustion are determined. The speed of the engine element during the explosion was evaluated and it was shown that during explosive combustion due to the large area and, accordingly, the mass flow, it is not possible to obtain a pressure value that could ensure the movement parameters registered in this engine design. Originality. Another criterion is established of engine operability when designing an engine on paste fuel. The effect of enrichment of pasty fuel with ammonium perchlorate during its flow through the supply system at the time of start-up was revealed. Practical value. The given information makes it possible to improve the design of the engine on paste fuel and to modernize the stand for its tests.