Research On The Ignition And Combustion Performance Of Gas Generator

The ignition characteristic and combustion performances of the gas generator are studied by means of theoretical analysis, experimental investigation and numerical simulation in the paper. The factors that have significant influences on the ignition process and combustion performances of the gas generator and the influence laws are respectively acquired. Several measurements that could improve the ignition characteristic and combustion performances of the gas generator are presented and verified by tests. The results are helpful to understand the inner operation process of the gas generator and important for application and optimization design of the gas generator.Key difficulties in the research of the gas generator are pointed out through theoretical analysis, so the main research contents are confirmed. The analysis shows that the ignition and combustion performances of the gas generator are markedly worsened although the combustion chamber temperature is lowered by adding water ; Combustion efficiency of the gas generator with Oxygen/ Lf80 is closely related to the evaporation rate of the liquid fuel of Lf80;The gas flow velocity being too high so the flame could not stay steadily in the combustion chamber is the main reason of the ignition difficulty in gas generator with Air/ Lf80-01 propellants.Based on the theoretical analysis and experimental results, the primary factors affecting markedly the ignition characteristic of the gas generator as well as the influence laws are studied. The results indicate that the combustion gas temperature plays the most important role on the ignition capability of the torch igniter. For gas generator, the ignition difficulty mainly comes from the addition of water that slows down the chemical reaction rate and flame propagation speed. The results also indicate that many factors have obvious influence on the ignition characteristic of the gas generator, including the temperature of the igniting combustion gas of torch igniter, the water fraction of the special fuel, the gas flow velocity in the combustion chamber, excess oxidizer coefficient and mass flux of propellants. On the foundation of the research, the paper presents a right method outstandingly improving the ignition reliability of the gas generator.The combustion performance of the gas generator with Oxygen/ Lf80 propellants is studied by experiments and numerical simulation. The influence on the combustion performance of the gas generator of injector structures, water fraction of liquid fuel, disturbing ring, excess oxidizer coefficient and mass flux are studied by experiments.According to the numerical simulation, the combustion characteristics of the gas generator with disturbing ring are analyzed. The results show that addition of water has a notable effect on lowering the combustion temperature since the whole combustion chamber has a low temperature. The evaporation rate is the essential factor, which has great influence on the combustion efficiency of the gas generator, so the efficient method to increase the combustion efficiency is to speed up the evaporation. The combustion efficiency can also be notably improved by optimizing the injector structure, decrease the water fraction of fuel and fixing the disturbing ring in the combustion chamber through which the combustion stability is also improved.