基于液体碳氢燃料的旋转爆轰燃烧特性研究

为了探索液体碳氢燃料参与旋转爆轰所产生的不完全燃烧现象，采用守恒元与求解元方法，开展柱坐标系下的汽油/空气两相旋转爆轰燃烧室三维数值模拟研究，针对燃料喷注压力和反应物当量比对旋转爆轰流场结构及燃烧室性能的影响进行分析。分析结果表明:保持总当量比为1.00，随着燃料喷注压力的上升，燃烧室内燃料不均匀分布增强，产生局部富燃区，燃料在燃烧室未能完全反应，导致燃烧室燃料比冲下降；保持喷注压力不变，减小当量比，在贫燃工况下依然存在局部富燃区，导致燃烧室内出现不完全燃烧现象，降低燃烧室比冲性能。由此可知，反应物喷注方案对气液两相旋转爆轰的不完全燃烧有显著影响。

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.