基于CFD流场特性分析发动机进排气系统设计  

Design of Engine Intake and Exhaust System based on CFD Flow Field Characteristics

作　　者：郭晟[1] 于国庆[2] GUO Sheng;YU Guo-qing(Department of Modern Manufacturing Engineering,Yibin Vocational and Technical College,Sichuan Yibin 644000,China;Hebei University of Science&Technology,Hebei Shijiazhuang 050018,China)

机构地区：[1]宜宾职业技术学院现代制造工程系,四川宜宾644000 [2]河北科技大学,河北石家庄050018

出　　处：《机械设计与制造》2021年第10期133-137,共5页Machinery Design & Manufacture

基　　金：四川省教育厅科研项目(18ZB0673)。

摘　　要：进排气系统是发动机重要的附属结构,对保证发动机正常工作具有重要意义。根据发动机进排气系统的结构特点,针对进气系统、排气系统、消声器等进行选型设计和结构设计;保证各部分结构满足发动机的压力和流量要求;采用理论分析计算、CFD建模仿真分析、试验台验证分析等相结合的方法进行设计分析。对排气管和消音器进行三维计算流体模拟仿真,得到速度场、压力场的分布图,并对设计关心的进出口压差进行计算;特别对消声器的穿孔板部分采用了多孔阶跃边界条件进行处理;采用试验方法对消声器设计进行验证。结果可知:空滤器进气阻力(滤芯干净时):8英寸/237mm水柱高度;管道总阻力为2.079英寸/52.8mm水柱高度;单个最大流量是:972.27L/s>904.5L/s,满足发动机要求;排气系统的排气管路和消声器总压损为3.52KPa,满足发动机排气背压要求;系统的CFD分析结果表明管道布局合理,无真空区和负压区,气流顺畅;试验结果表明,消声器消声效果最高可达40dBA;而达到发动机的排气流量流速时,压力损失为1869.12Pa,而设计值为1802.38Pa,二者的误差为3.72%,结果基本一致,表明设计结果可靠;为同类设计提供参考。The intake and exhaust system is an important accessory structure of the engine,which is of great significance to ensure the normal operation of the engine.According to the structural characteristics of the engine intake and exhaust system,the selection design and structural design for the intake system,exhaust system,muffler,etc.Ensure that all parts of the structure meet engine pressure and flow requirements.Design analysis uses a combination of theoretical analysis and calculation,CFD modeling and simulation analysis,test bench verification analysis,etc.The three-dimensional computational fluid simulation of the exhaust pipe and the muffler is carried out to obtain the distribution map of the velocity field and the pressure field,and calculate the pressure difference between the inlet and outlet of the design.In particular,the perforated plate portion of the muffler is treated with a porous step boundary condition.And verify the muffler design using test methods.The results show that the air filter inlet resistance(when the filter is clean):8 inches/237mm water column height.The total resistance of the pipeline is 2.079 inches/52.8 mm water column height.The single maximum flow is:972.27L/s>904.5L/s,which meet engine requirements.The total pressure loss of the exhaust system and muffler of the exhaust system is 3.52kPa,which satisfies the engine exhaust back pressure requirement.At the same time,the CFD analysis results of the system show that the pipeline layout is reasonable,no vacuum zone and negative pressure zone,and the airflow is smooth.Test results show that the muffler has a noise reduction effect of up to 40dBA.When the engine exhaust flow rate is reached,the pressure loss is 1869.12Pa,and the design value is 1802.38Pa.The error between the two is 3.72%.The results are basically the same,indicating that the design result is reliable;provide reference for similar design.

关 键 词：汽车 发动机 进排气系统 流场特性 计算流体力学 模型 

分 类 号：TH16[机械工程—机械制造及自动化] P733.22[天文地球—物理海洋学]