高压共轨直喷柴油机缩口燃烧室内混合气形成的多维数值研究  

Multi-dimensional numerical study on mixture formation in reentrant combustion chamber of high-pressure common-rail direct-injection diesel engine

作　　者：林学东[1] 田维[1] 黄丫[1] 李德刚[1] 刘忠长[1] 

机构地区：[1]吉林大学汽车动态模拟国家重点实验室,长春130022

出　　处：《吉林大学学报（工学版）》2010年第2期363-369,共7页Journal of Jilin University:Engineering and Technology Edition

基　　金：国家自然科学基金项目(59676028)

摘　　要：改进设计了高压共轨直喷式柴油机缩口型燃烧室,利用FIRE软件针对不同燃烧室结构对燃烧室内气流特性的影响进行了多维数值模拟。研究了高压共轨喷射系统与缩口直喷式燃烧室匹配时不同喷射参数对燃烧室内流场、浓度场和温度场分布特性的影响,以及混合气形成过程的微观特性。研究结果表明:改进后的缩口直喷式燃烧室能够合理地利用喷雾的动能,提高燃烧室内的气流强度及其保持性,从而加强燃烧开始后燃油与空气的混合能力,促进扩散燃烧过程。因此,合理的燃烧室形状配合喷射时刻和压力的有效控制能在提高发动机性能的同时降低排放,是高压共轨直喷式柴油机实现高效率低排放的有效途径。To improve the shape of the reentrant combustion chamber of a high-pressure common-rail direct-injection diesel engine,3-D CFD simulations were performed using the software FIRE to investigate the effect of the combustion chamber geometry on the in-cylinder flow field characteristics.The microscopic characteristics of the air-fuel mixture formation process as well as the effect of the fuel spray on the flow field,air-fuel ratio field,and temperature field were studied as the reentrant combustion chamber matched with different fuel injection parameters.The results show that in the improved combustion chamber,it can make full use of the kinetic energy of the fuel spray to increase the intensity and the preserving ability of the air flow,thus enhance the air-fuel mixing during the combustion period,promote the diffusion combustion process.Therefore,the reasonable combustion chamber shape matched with the appropriate fuel injection timing and pressure can effectively improve the efficiency and reduce the exhaust emissions of the high-pressure common-rail direct-injection diesel engine.

关 键 词：动力机械工程 直喷式柴油机 高压共轨 缩口燃烧室 数值模拟 流场 喷雾 

分 类 号：TK421[动力工程及工程热物理—动力机械及工程]