【摘要】 以二甲基醚着火反应机理和热力学燃烧模型为基础,建立了二甲基醚着火数据库及发动机工作过程的数学模型,藉此进行了发动机的循环模拟计算.计算结果与验证实验结果对比表明,Wiebe模型、Watson模型和Whitehouse-Way模型均可应用于二甲基醚发动机工作过程的模拟计算.应用化学反应动力学模型对DME发动机着火过程模拟计算结果所建立的着火数据库表明,滞燃期是缸内温度、压力和燃空当量比的函数,在一定的燃空当量比范围内,着火滞燃期随燃空当量比增大而变小.而采取将着火数据库与Watson燃烧子模型相耦合的模拟计算能够与实验结果相吻合.更多还原

【Abstract】 Based on the kinetics mechanism of the ignition reaction and thermodynamic combustion sub-model of the engine fuelled with dimethyl ether, an ignition delay database library and working process simulation of the engine were set up. The comparisons computational to experimental data showed that combustion sub-models such as Wiebe model, Watson model and Whitehouse-way model are suit to predict the performance characteristics of engines operated on DME. The ignition delay database library developed on the numerical calculation results by using a detailed chemical kinetic model for the ignition process of DME engine indicated that the ignition delay is the functions of temperature, pressure and fuel/air equivalence ratio. In a certain range of fuel/air equivalence ration, the ignition delay becomes shorter with the increase of fuel/air equivalence ratio. The coupling of the Watson model with the ignition delay database library would show better results for predicting the engine performances.更多还原