多孔介质发动机流动与燃烧特性的大涡模拟初探  

Preliminary Investigation on Flow and Combustion Characteristics of PM Engines with Large Eddy Simulation

作　　者：周磊[1] 解茂昭[1] 贾明[1] 史俊瑞[2] 

机构地区：[1]大连理工大学能源与动力学院,辽宁大连116024 [2]沈阳工程学院动力系,辽宁沈阳110136

出　　处：《内燃机学报》2011年第2期125-132,共8页Transactions of Csice

基　　金：国家自然科学基金资助项目(50806008);国家基础研究重点计划资助项目(2007CB210002)

摘　　要：对多孔介质发动机的燃烧特性采用大涡模拟进行了初步分析.首先计算了考虑多孔介质随机结构特性的定容燃烧室内气体燃料喷射过程,并与自由空间中的喷射过程进行了对比.然后采用大涡模型对两种结构形式的多孔介质发动机的燃烧过程进行了初步的计算分析.多孔介质的存在增强了湍流涡团的小尺度结构,明显改变了燃料的空间分布,而采用大涡模拟(LES)方法得到的气体喷射流场较之RANS模型具有更强的不规则度.两种模型计算的燃烧特性也有一定差别.最后,对多孔介质发动机和没有安装多孔介质的发动机进行了对比.结果表明,多孔介质对发动机燃烧所起作用是很明显的,有望实现均质压燃并显著降低排放.A preliminary LES analysis on the flow and combustion characteristics of porous media（PM） engines was conducted.Gas fuel injection process in a constant volume vessel was computed by using a PM model which takes into account the random structure of porous media,and compared with that in the same vessel but without PM insert.Combustion processes in two PM engines with different configurations were predicted using both LES and RANS models.It is demonstrated that transient small-scale structure of turbulent eddies is enhanced and fuel distribution is changed due to the presence of the porous media.Compared to the RANS model,the flow field due to gas injection obtained by LES is more irregular.There are also certain differences between the combustion characteristics computed by the two models.Comparisons between the engines with and without PM show that the PM exerts a remarkable and positive effect on improving engine efficiency and reducing emissions.

关 键 词：大涡模拟 多孔介质发动机 气体燃料 随机结构 

分 类 号：TK402[动力工程及工程热物理—动力机械及工程]