柴油机冷启动喷雾油滴撞壁速度效应数值分析  

Effect of Impacting Velocity on Spray Oil Droplet Impacting onto a Surface during Diesel Engine Cold Starting

作　　者：李大树 仇性启[1] 崔运静[2] 郑志伟 马培勇[3] 祁风雷[4] 

机构地区：[1]中国石油大学(华东)化学工程学院,青岛266555 [2]中国石油大学(华东)机电工程学院,青岛266555 [3]合肥工业大学机械与汽车工程学院,合肥230009 [4]爱荷华州立大学工程学院,埃姆斯50011

出　　处：《农业机械学报》2014年第6期25-31,共7页Transactions of the Chinese Society for Agricultural Machinery

基　　金：'十二五'国家科技支撑计划资助项目(2012BAD30B01);国家自然科学基金资助项目(51006031);中央高校基本科研业务费专项资金资助项目(13CX02078A);安徽省自然科学基金资助项目(11040606Q40)

摘　　要：采用流体体积法并综合考虑液滴与壁面间传热及接触热阻的作用,建立了液滴冲击壁面数值模型,并开展实验验证了模型的可靠性。通过分析计算,揭示了液滴撞壁流动传热及破碎机制,并探索了液滴撞壁碰撞速度效应规律。研究表明:液滴最大铺展系数和碰撞点处热流密度与液滴碰撞速度密切相关;液滴达到最大铺展直径和恒定热流密度所需无量纲时间与碰撞速度不相关;燃料液滴换热量与雷诺数近似线性递增。从能量守恒方程出发,建立了液滴最大铺展系数理论解析模型,该解析解与数值解呈现出较好的一致性。In order to explore the mechanism of liquid film formed by fuel droplet impacting on surface in small-size combustor of diesel engine, a numerical model was developed using volume of fluid method including heat transfer and contact resistance and verified by experiments. The mechanism of droplet fluid and heat transfer as well as breakup during spreading were obtained according to the result analysis. The results also showed that the droplet maximum spreading factor and heat flux at impacting point were closely related to impact velocity, and the dimensionless time of maximum spreading factor and constant heat flux are uncorrelated to impacting velocity. The amount of heat transfer linearly increased with Reynolds number. The theoretical analysis model was also developed based on energy conservation equation, which showed a good agreement with numerical results.

关 键 词：柴油机 冷启动 喷雾油滴 碰撞速度效应 数值分析 

分 类 号：TK05[动力工程及工程热物理] TK124