Soot Formation Numerical Simulation in Reducing Gas Generators of Oxygen-Methane Liquid Rocket Engines

A method for numerical simulation of operating processes in reducing gas generators with calculation of the condensed phase (soot) formation process detailed structure has been developed. It is assumed that soot is formed from gas-phase fuel in two stages. At the first stage, active radical nuclei are formed, and at the second stage, carbon black particles are formed from these nuclei. Numerical modeling of processes, fuel mixing and combustion, as well as soot formation in model reducing oxygen-methane gas generators with gas-liquid coaxial mixing elements of jet-jet type has been performed. Gas generators of this type can be used in promising oxygen-methane liquid rocket engines operating on open and closed circuits with reducing gas generators, as well as on the gas-gas circuit having reducing and oxidizing gas generators. A comparative analysis of soot formation features in gas generators with single- and multi-nozzle mixing heads has been performed. It is shown that a decrease in the pitch between the mixing elements leads to a significant change in the mixture formation processes, fuel combustion and the flow of combustion products (all other conditions being equal), which significantly reduces the intensity of condensed phase formation in reducing gas generators. The numerical simulation method will be used for studies of fuel combustion and condensed phase formation in regenerative gas generators of modern and advanced liquid rocket engines at the stages of development, design and improvement