摘要
选择性催化还原(SCR)系统是柴油机脱除尾气NO_(x)的核心,喷嘴的雾化性能直接影响NO_(x)转化率及尿素结晶,压力旋流式喷嘴比直流式喷嘴更有性能优势.以新设计的一款压力旋流式喷嘴为对象,结合试验数据,基于流体体积函数(VOF)法,耦合喷嘴内旋流与喷嘴外近场喷雾开展三维数值模拟,精准获取旋流液膜厚度、液膜锥角.基于喷孔内部流场与索特平均直径(SMD)的关系模型,实现喷嘴结构对喷雾雾化性能的直接耦合研究,进而获得了旋流室长度、旋流室直径、出口段长度和出口段孔径等压力旋流式喷嘴关键结构参数对喷雾性能的影响特性,结果表明:喷嘴几何参数调整需由气核生长情况判断;当气/液两相分界面呈多级阶梯型时,减小旋流室长径比、出口段长径比均可有效降低喷雾粒径,增强雾化效果.该新设计的压力旋流式喷嘴具备SMD小于30μm的潜力.
Selective catalytic reduction(SCR)system is the core of diesel engine to remove NO_(x) from exhaust gas.The atomization performance of urea nozzle directly affects the NO_(x) conversion rate and crystallization of urea.The pressure swirl nozzle has more performance advantages than the simplex nozzle.Taking a newly designed pressure swirl nozzle as the research object,combined with the experimental data and the volume of fluid(VOF)method,a three-dimensional numerical simulation was carried out by coupling the swirl inside the nozzle and the near-field spray outside the nozzle.The thickness and cone angle of the liquid film were accurately obtained.Based on the mathematical model of the flow field inside the orifice and Sauter mean diameter(SMD),the coupling study of the nozzle structure on the atomization performance of the spray was realized.The influence of key structural parameters of the pressure swirl nozzle,such as the length of the swirl chamber,the diameter of the swirl chamber,the length of the orifice and the diameter of the orifice,on the spray performance were analyzed.The results show that the geometrical parameters of the nozzle should be adjusted according to the growth of the gas core.When the interface between the gas phase and the liquid phase presents a multi-stage staircase pattern,reducing the ratio of length to diameter of the swirl chamber and orifice can effectively reduce the particle size and enhance the atomization effect.The newly designed pressure swirl nozzle has the potential of SMD less than 30μm.
作者
王翀
何志霞
张亮
钟汶君
李琛
Wang Chong;He Zhixia;Zhang Liang;Zhong Wenjun;Li Chen(Institute for Energy Research,Jiangsu University,Zhenjiang 212013,China;School of Power and Engineering,Jiangsu University,Zhenjiang 212013,China;Kailong High Technology Company Limited,Wuxi 214000,China)
出处
《内燃机学报》
EI
CAS
CSCD
北大核心
2024年第4期317-324,共8页
Transactions of Csice
基金
国家自然科学基金资助项目(52376113)。
关键词
柴油机
SCR系统
压力旋流式喷嘴
喷雾
diesel engine
selective catalytic reduction system
pressure swirl nozzle
spray
作者简介
王翀,硕士研究生,E-mail:981287488@qq.com;通信作者:何志霞,博士,教授,E-mail:zxhe@ujs.edu.cn.
