摘要
针对螺旋槽管式废气再循环系统(EGR)冷却器强化换热引起流动阻力增大的问题,通过计算流体力学(CFD)仿真计算及试验探究螺旋槽管式EGR冷却器流体换热性能后,提出螺旋翅片与螺旋槽管配合的新型EGR冷却器.通过CFD法将优化结构与光管、螺旋槽管、螺旋翅片-光管式冷却器进行对比,对螺旋翅片的高、长及螺距于流动换热的影响进行仿真预测.结果表明:螺旋槽管式EGR仿真与试验结果对比显示换热系数最大偏差3.9%,压降值最大偏差6.8%,在工程应用接受范围内,保证了分析方法的可靠性.螺旋翅片-槽管式EGR冷却器相比螺旋槽管式能增强换热并减小流阻,翅片形成螺旋流与螺旋槽形成螺旋流相似,能减小流阻近20%,翅片产生的螺旋流使螺旋槽处扰流效果增强,较螺旋槽管式冷却器出口温度最大下降4.5%;螺旋翅片总长增大半个螺距长度,出口温度最大降幅达6.2%,螺距长度按160mm均分,每减少一个螺距,对应流阻降幅达10%,翅片高度对性能影响不大,适当减小尺寸可减少加工材料,节约成本.
Aiming at the problem of the increasing flow resistance caused by the heat transfer of the spiral groove tube EGR cooler,the heat transfer performance of spiral groove tube in EGR cooler was analyzed through numerical simulation method,which was compared with bench test.The optimization structure of spiral finned groove tube was proposed.A comparative analysis was conducted among the light tube,the spiral groove tube,the spiral finned light tube and the spiral finned groove tube.The influence of height,length and pitch of the spiral fins on the flow and heat transfer characteristics was analyzed.Results showed that the maximum deviation of heat transfer coefficient caculated from the numerical simulation and experiment method for the spiral groove tube EGR cooler was 3.9%and that for pressure drop was 6.8%,which was acceptable in engineering application and ensured the reliability of analysis method.The spiral finned tube EGR cooler can enhance heat transfer performance and reduce flow resistance.The spiral flow created by fin is similar to that created by spiral groove tube,which can reduce the flow resistance by20%,and the spiral fin can enhance the disturbance flow that created by the spiral groove tube.As a result,the outlet temperature drops by 4.5%.The maximum outlet temperature drops by 6.2%,as the total length of the spiral fin increases by half a pitch.The flow resistance increases by 10%,while one more pitch is added in fixed length of 160 mm.Results show that height affects little.Appropriatereduction of the size of height can reduce processing materials and save cost.
出处
《浙江大学学报（工学版）》
EI
CAS
CSCD
北大核心
2016年第8期1507-1515,共9页
Journal of Zhejiang University：Engineering Science
关键词
EGR冷却器
仿真
光管
螺旋槽管
螺旋翅片
EGR cooler
numerical simulation
plain tube
spiral groove tube
spiral finned groove tube
