基于三维建模和数值模拟的CNG发动机进气系统分析

Analysis on Intake System of CNG Engine Based on 3D Modeling and Numerical Simulation

发动机进气系统的结构直接影响到发动机各缸的燃烧情况以及热负荷等各项性能,利用CFD技术建立三维流动模型,根据CFD计算经验将进气管内的气体流动视为三维可压缩定常流动。根据进气系统的CAD图利用GAMBIT软件建立三维模型并进行网格划分,最后用FLUENT软件进行三维流动的模拟计算,得到流场内各处流体速度的分布和变化情况,计算出各歧管出口处的流体质量流量,并分析了进气的不均匀性。

A 3D flow model of intake system in CNG engine is built by using CFD technology. The gas flow in intake pipes is considered as a 3D compressed steady flow based on CFD experience. According to the CAD drawing of air intake system,a 3D model grids is built with the help of CAMBIT software. Finally,the FLUENT software is used to establish a 3D flow simulation, and then the fluid velocity distribution in flow field is obtained. The fluid mass flow at the exit of each manifold＇is calculated,and the inhomogeneity of the inlet air is also analyzed.