泡沫陶瓷中燃油喷雾液滴蒸发混合的数值研究

将孔隙率0．85的泡沫陶瓷简化为由128个正方形格栅等间距排列构成的区域,在二维计算区域中,用反弹模型模拟液滴与泡沫陶瓷及边界壁面碰撞后液滴运动轨迹的变化．在不同的栅格壁面温度、喷雾锥角及燃料喷雾速度时,在常压及层流状态下,研究喷雾液滴在泡沫陶瓷中的蒸发特性．计算结果表明,泡沫陶瓷温度是决定燃油蒸发速率的关键因素;大喷雾锥角时,燃油蒸气分布较均匀;减小喷雾速度会使燃油蒸气分布不均匀．

Numerical Investigation of the Spray Droplets Evaporation and Mixing Inside Ceramic Foam

The ceramic foam with porosity of 0. 85 was modeled by an array consisting of 128 rectangles distributed regularly in a two-dimensional computational domain. The process of droplets impingement on the walls was simulated with the rebound model. By changing the temperature of ceramic foam wall, spray cone angel and injection speed, the evaporation and mixing of fuel droplets were investigated numerically under laminar and 0. 101 MPa condition. The simulation results show that the temperature of ceramic foam wall is the key factor for determining the fuel evaporation rate. The fuel vapor distributes more homogeneously at bigger spray angle, and less homogeneously at low injection speed.