Combustion characteristics of rotating detonation based on liquid hydrocarbon fuel

The liquid hydrocarbon fuel droplets need to be broken up and vaporized before further participating in detonation combustion, resulting in a more complex phenomenon in liquid-hydrocarbon fueled rotating detonation combustors (RDCs). To explore the incomplete combustion phenomena in liquid hydrocarbon-fueled rotating detonation, the conservation element and solution element method (CE/SE method) was used to simulate a two-phase three-dimensional RDC fueled with a liquid gasoline/air mixture. The Euler-Euler model was used to establish the three-dimensional gas-liquid two-phase governing equations in the cylindrical coordinate system. The source terms were solved by the fourth-order Runge-Kutta method. The phase transition was described by the droplet stripping and evaporation model. Furthermore, the energy and momentum exchange between the two phases was considered. The internal energy of the components was calculated from the enthalpy values of the polynomial fitting and the temperature was solved by Newton iteration. The injection conditions of the gas and liquid phases were assigned by different back pressures. The reactant equivalence ratio can be obtained by the area ratio of the droplets and the gas flow. The effects of the injection pressure and the equivalence ratio on the structure and performance of the rotating detonation flow field were analyzed. When the total equivalent ratio is fixed to 1.00, the inhomogeneous distribution of the fuel in the combustor is enhanced with the increase of the fuel injection pressure, resulting in some local fuel-rich areas. The fuel fails to completely combust in the combustor, leading to a decrease of the specific impulse. With a constant injection pressure and a reduced equivalent ratio, there are still local fuel-rich areas, resulting in incomplete combustion and reduced specific impulse performance. The results show that the reactant injection scheme has a significant effect on the incomplete combustion of the gas-liquid two-phase rotating detonations. © 2022, Editorial Staff of EXPLOSION AND SHOCK WAVES. All right reserved.