液态LPG喷射发动机混合气分层构造的数值模拟  

Numerical simulation for mixture stratification of liquid LPG injection engine

作　　者：耿德强[1] 贾咸昆[1] 许伯彦[1] 

机构地区：[1]山东建筑大学机电工程学院,山东济南250101

出　　处：《山东建筑大学学报》2008年第1期20-26,共7页Journal of Shandong Jianzhu University

基　　金：国家自然科学基金资助项目(50576047)

摘　　要：提出了电控液态LPG喷射发动机通过采用前端向内弯曲的进气道和向内呈渐缩形布置的隔板,同时配合使用凹面弯曲活塞顶的结构实现分层稀薄燃烧的方法。使用60%(摩尔比)丙烷和40%(摩尔比)正丁烷的混合气作为LPG燃料,在查找、计算、建立LPG混合气自0K至临界温度的13种物性参数的数据库后,利用Fortran语言编写了描述LPG的物化特性的自定义函数,导入到通用CFD软件Fire中,考虑到LPG的闪急沸腾现象,修改了Fire自带的蒸发模型。对发动机部分负荷下的分层混和气形成过程进行了数值模拟,通过缸内速度矢量图和燃料浓度场的分布,分析了缸内滚流和混合气分层构造的形成过程。A method of lean stratified combustion was proposed for electronic control liquid LPG injection engine with the front-end inward bending intake port and inward-shaped layout with the gradual reduction clapboard and the concave curved structure piston. The mixture of 60% （mole ratio） propane and 40% （mole ratio） n-butane was used as a calculated fuel because of its similar properties in chemical and physical to LPG. A database programmed with Fortran for LPG physical and chemical properties varying from 0 K to critical temperature has been imported into the CFD code. Taking into account the flash boiling phenomena of LPG, the evaporation model of Fire was amended. In this paper, a numerical simulation was performed using Fire, where the process of stratified gas mixture formation was investigated under part of the engine load. Through the in-cylinder velocity vector figure and the distribution of fuel concentration field, the process was investigated of in-cylinder tumble and mixture stratification formation.

关 键 词：LPG 数值模拟 闪急沸腾 分层混合气 

分 类 号：TK432[动力工程及工程热物理—动力机械及工程]