直喷式柴油机缸内气体运动和燃油喷雾的二维数值分析

本文应用任意拉格朗日-欧拉法(ALE)对直喷式柴油机缸内气体运动及燃油与空气的混合过程进行数值模拟。采用二维轴对称坐标系和按规定速度运动的任意四边形网格单元,燃烧室可具有较复杂的几何形状。燃油喷雾用气体射流模拟。湍流模型采用简化的亚网格尺度湍流粘性公式。对两台具有伞喷系统的柴油机做了模拟计算,其结果与实验相吻合。

TWO-DIMENSIONAL NUMERICAL ANALYSIS OFIN-CYLINDER AIR MOTION AND FUEL SPRAY IN DIRECTINJECTION DIESEL ENGINES

The ALE method is used to simulate the air motion and the fuel-air mixing in cylinders of D. I. diesel engines. Two-dimen-sional axisymmetrical coordinates and mesh cells with the shape of an arbitrary quadrilateral are employed, which can move with a pre-scribed velocity. The combustion chamber may be complex geometrically. The effects of turbulence are modeled with a simplified subgrid-scale eddy viscosity. The fuel spray is simulated by a gaseous jet. Sample computations have been carried out for two test engines with the hol-low-cone-spray combustion system. The results are in good agreement with experiments.