Numerical study of hydrogen hydrothermal combustion characteristics in a coaxial nozzle burner

This study aims to investigate the characteristics of hydrogen hydrothermal combustion in a coaxial nozzle burner (CNB). A computational fluid dynamics model, which is validated against the experimental data, is developed to simulate the flow field, the flame stabilization process, and the influence of different operating conditions on combustion in the CNB. Results show that the combustion primarily occurs in a V-shaped zone downstream of the injector, where the recirculation zone makes reactants flow back and enhances turbulence and heat transfer. The gravity in the same direction as the jet shortens the length and width of the flame, making the combustion zone move closer to the nozzle outlet. The increase in feed temperature and concentration can promote the kinetic rate along with the peak temperature. The feed flow rate mainly affects the axial temperature gradient near the nozzle outlet by changing the residence time of the reactants.