Abstract: The filter was simplified into a series of pipes with different diameters，and a model of a new type of dry and wet composite air filter in series connection was established.The non-circular cross section of pipeline was simplified into a circular cross section of pipeline，and the equivalent diameter of the non-circular cross section of pipe was used to replace the diameter of the circular pipe.Furthermore，the steel wire mesh and filter core in the air filter were also simplified into porous media.The total pressure drop of the pipeline system was the sum of the pressure loss along the flow paths and the local pressure loss.The proposed model was expressed as a function of the frictional resistance coefficient λ，local resistance coefficient ζ，penetration rate K，fluid density ρ，fluid velocity v and so on.The results show that most of the pressure drop of dry and wet composite air filter is concentrated in the coarse filter and fine filter，and most of it is concentrated in the steel wire mesh of the coarse filter.And the calculated results are compared with the experimental and simulation results，which verify the rationality of the model.

Key words: vehicle engineering；air filter, pressure drop, series, simplify, porous media

摘要： 将滤清器简化成由多段不同管径的管道串联而成，建立了一种新型的干湿复合式空气滤清器的串联模型。把非圆形截面管道简化成圆形截面管道来分析，用非圆形截面管道的当量直径来代替圆管直径；把钢丝滤网和滤芯部分简化成多孔介质来分析。整个管路系统的压力损失等于沿程压力损失和局部压力损失之和。所得到的模型是紊流沿程阻力系数λ、局部阻力系数ζ、穿透率K、流体密度ρ、流体平均速度v等的函数。计算结果表明：干湿复合式空气滤清器的压力损失大部分集中在粗滤和精滤部分，且大部分是集中在粗滤部分的钢丝滤网部分，并将计算结果与相关实验以及仿真结果进行对比，验证了模型的合理性。

关键词: 车辆工程, 空气滤清器, 压力损失, 串联, 简化, 多孔介质