点火参数对煤油活塞发动机燃烧影响的数值模拟

为了了解点火参数对某2冲程航空活塞煤油发动机燃烧及温度场的影响,利用GT-Power和Fire软件对该发动机整机及燃烧室分别建立了仿真模型,选取扭矩、功率以及缸压数据验证了该模型的正确性,并对发动机在6000 r/min、全负荷工况下的燃烧和温度场分布等特性进行分析.结果表明:当点火时刻由335°CA变化至331°CA时,缸内混合气燃烧放热量增多,放热率峰值增大,放热率峰值对应曲轴转角的提前量变大,燃烧放热速率加快,混合气温度和压力上升变快,高温区范围增大;当点火能量由28.02 mJ增加至46.73 mJ时,双火花塞附近的温度升高,火花塞点火产生的火核尺寸增大,缸内燃烧温度与压力升高,燃烧放热速率加快,缸内高温区分布范围增大.

Numerical Simulation on Influence of Ignition Parameters on Combustion of Kerosene Piston Engine

In order to understand the influence of ignition parameters on combustion and temperature distribution of two-stroke kerosene piston engine, the simulation models of engine and combustor were established respectively using GT-Power and AVL Fire. The experiment data of torque, power, and cylinder pressure have been selected to verify the correctness of the model. The combustion and temperature distribution were analyzed at the 6000 r/min and full load condition. The results show that: when ignition time varied from 335 to 331° CA to ignite the air/fuel mixture in the cylinder, the greater the amount of the advance ignition timing, the amount of the combustion heat release increased, the peak of heat release rate increased and appeared earlier, the heat release rate of combustion was faster, the mixed gas temperature and pressure rose faster, the range of high temperature zone increased; when the spark plug ignition energy increased from 28.02 to 46.73 mJ to ignite the air/fuel mixture in the cylinder, the temperature increased in the vicinity of the dual spark plug, the flame kernel size increased, the temperature and pressure increased, the heat release rate of combustion was faster, the range of high temperature zone increased.