【摘要】 基于Converge软件建立了包含简化化学反应机理的氢燃料内燃机CFD仿真模型,研究了氢燃料内燃机缸内燃烧和NO生成机理。仿真结果表明,氢燃料内燃机缸内燃烧经历了椭球型火焰稳定传播和快速湍流燃烧两个阶段。氢气的燃烧非常迅速,在快速湍流燃烧结束时OH浓度迅速降低,出现温度和NO质量峰值,其后缸内温度逐渐降低,NO质量逐步减小。最终的排放取决于高温区域的峰值温度和NO分解时间。最高温度越高NO的质量峰值越大,降温越快则NO分解越少。采用EGR能降低最高缸内温度,低转速时NO分解充分,因而NO的排放较低。更多还原

【Abstract】 The CFD simulation model of a hydrogen-fueled internal combustion engine(HICE) including the simplified chemical reaction mechanism was established based on Converge software and the in-cylinder combustion progress and NO generation characteristics of HICE were studied. The simulation results show that the in-cylinder combustion progress is composed of ellipsoid flame stable propagation and rapid turbulent combustion in turn. Due to the very rapid combustion of hydrogen, the OH concentration decreases rapidly at the end of turbulent combustion and the temperature and NO mass reach the peak, then the in-cylinder temperature and NO mass decrease gradually. The final emission depends on the peak temperature and NO decomposition time in the high-temperature area. The peak of NO mass increases with the increase of peak temperature and the NO decomposes less due to faster temperature decrease. The maximum in-cylinder temperature becomes lower by using exhaust gas recirculation(EGR) and NO decomposes completely at low speed, which leads to lower NO emissions.更多还原