LPG发动机稀燃流场优化及排放特性研究  

Optimization of Lean Combustion Flow Field and Emission Characteristics of LPG Engine

作　　者：李思成 姚玉南[1] LI Sicheng;YAO Yunan(School of Energy and Power Engineering, Wuhan University of Technology, Wuhan 430063, China)

机构地区：[1]武汉理工大学能源与动力工程学院

出　　处：《船舶工程》2019年第5期67-72,共6页Ship Engineering

基　　金：国家自然科学基金(51179144);武汉理工大学自主创新研究基金项目(2017-ND-A1-02)

摘　　要：将传统燃油发动机改装为LPG稀燃发动机,并在进气口处安装涡流挡板,该挡板可根据发动机负载进行不同进气模式切换,以达到分层燃烧和均质燃烧。然后,建立LPG发动机三维数值仿真模型,分别进行稳态、瞬态流场优化以及缸内油气分布数值计算,并对稀薄燃烧试验与仿真结果进行对比。结果表明:均质模式与分层模式下的稳态流场分析结果与试验结果相吻合,流量系数误差均在6%以内;瞬态流场结果显示,分层模式下进气气流因涡流挡板作用,气缸涡流增强,燃料能有效地集中在火花塞中心,火花塞周围则为较稀的混合气,形成油气高度分层分布状态,从而提高稀薄燃烧极限,降低LPG发动机CO2、NOX排放量。The traditional fuel engine is converted to LPG lean burn engine, and a swirl baffle is installed at the intake port, which can be switched between different intake modes according to the engine load to achieve stratified combustion and homogeneous combustion. Then a three-dimensional numerical simulation model of LPG engine is established to optimize the steady and transient flow fields and calculate the distribution of oil and gas in cylinder respectively. The simulation results are compared with the lean combustion experiments. The results show that steady state flow field in homogeneous mode and stratified mode is consistent with the experimental results, and the error of flow coefficient is less than 6%. The transient flow field shows that the air flow in the cylinder is enhanced by the diversion of the swirl baffle in the stratified mode. The fuel can be effectively concentrated in the spark plug center and the mixture around the spark plug is thinner, thus a highly stratified distribution of oil and gas is formed,which increase the limit of dilute oil and reduce the emission of CO2 and NOX of LPG engine.

关 键 词：LPG发动机 稀薄燃烧 稀薄燃烧极限 流场分析 排放特性 

分 类 号：TK431[动力工程及工程热物理—动力机械及工程]