Simulation study on combustion flow in low-pressure condition of hydrogen-oxygen torch ignitor

The effects of hydrogen-oxygen injection interval and droplet mean diameter on the combustion flow of the low-temperature liquid hydrogen and liquid oxygen torch electric ignitor in low-pressure condition were investigated by numerical simulation.Discrete phase model（DPM） and 16-step，6 species hydrogen-oxygen chemical reaction mechanism were applied for the analysis.Considering the turbulent combustion effect，the eddy dissipation concept combustion model was utilized for simulation calculation.The temperature results obtained by simulation were in good agreement with those obtained by experiment，and the deviations of pressure were within 5%，thereby verifying the accuracy of the numerical models.As the results shown，under low-pressure condition，when the hydrogen-oxygen injection interval increased，the ignitor head inner wall temperature increased，the chamber pressure decreased，and the combustion length decreased.The larger liquid hydrogen droplets diameter resulted in the longer combustion length and higher head inner wall temperature，besides，the pressure in the ignitor chamber was slightly reduced.The diameter of liquid oxygen droplets had little effect on combustion flow of the ignitor.