4. Thermal decomposition of hydrogen peroxide in the combustion zone of a gas generator. Simulation of the process

Annotation: Two models have been developed to investigate the thermal decomposition of concentrated hydrogen peroxide: in a fl ow of high-temperature decomposition products (1) and for an analysis of properties of decomposed products after a catalyst bed (2). The fi rst model assumes steady, adiabatic fl ow and accounts for mass balance conditions, drop evaporation, decomposition in the gas phase, and conservation laws for a volume under analysis. The model considers various CHP concentration levels for both primary and secondary fl ows, mass fl ow rates for both fl ows, and initial temperatures of liquid CHP fed to diff erent zones of the preburner. The second model is suitable for analyzing the properties of decomposition products after a catalyst, where the complete decomposition of concentrated hydrogen peroxide occurs. The parameters of steam gas are determined by energy balance in a CHP decomposition reaction. This model also accounts for the concentration of liquid CHP and its initial temperature. The analysis results for the fi rst model indicate the signifi cant eff ect of droplet size and the rate of the secondary injectant fl ow on the decomposition process. In general, the results demonstrate a limitation for the amount of the secondary fl ow (the mass of the secondary fl ow should not exceed ~30–40 % of the total mass in the preburner volume under analysis, as the process of liquid hydrogen peroxide evaporation consumes heat from the primary fl ow, and its temperature drops at the beginning of the mixing zone). The results also reveal that the optimal droplet size of injectant fl ow exists, caused by the admissible time of residence in the preburner’s fl ame zone. The droplet size also impacts the allowable level of local temperature drop at the CHP injection area: the smaller the drop size, the more intense the evaporation, and the more heat is consumed from the high-temperature gas. A simplifi ed analysis of properties of CHP decomposition products is off ered, assuming the mass fl ow rate of the secondary fl ow is less than ~25 % of the total amount.