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根据二甲醚发动机燃烧过程的特点,提出一种湍流燃烧模型。该模型在传统化学动力学模型的基础上,增加了拟序火焰片湍流燃烧模型以考虑湍流对燃烧的促进作用。数值模拟表明,二甲醚在发动机中油束贯穿度比柴油短;油孔附近的油束上边缘处具有合适的燃料浓度和较高温度,最先发生自燃;在扩散燃烧时燃料与空气混合速度慢,燃烧速度慢,持续时间长。计算结果与试验观察基本相符。
According to the characteristics of DME engine combustion process, a turbulent combustion model is proposed. Based on the traditional chemical kinetic model, the model adds a turbulent combustion model of the pre-programmed flames to consider the effect of turbulence on combustion. Numerical simulations show that DME has a lower penetration rate of diesel fuel in the engine than diesel fuel. The upper edge of the oil bundle near the oil hole has suitable fuel concentration and high temperature, and spontaneous combustion occurs first. At the time of diffusion combustion, the mixing speed of fuel and air Slow, slow burning, long duration. The calculated results are in good agreement with the experimental observations.