摘要
为了进一步探究具有不同截面高宽比的单一螺旋通道内流体湍流流动与换热特性以及射流对矩形截面螺旋通道的强化传热效果,采用计算流体动力学软件模拟研究了高宽比γ分别为0.625,1.1,1.6和2.5时,单一矩形螺旋通道及射流作用下螺旋通道内的湍流流场、二次流场及强化换热特性。结果表明,对于单一矩形螺旋通道,相同横截面积和流量时,仅当γ≥1.6的通道在高雷诺数下二次流会出现四涡结构,其余为两涡结构。对于单一螺旋通道,γ值越大流动阻力越小,同时换热性能越差。加入射流后,矩形截面四个壁面的换热能力均有提高,γ值越大射流的强化传热效果越显著,研究范围内局部壁面换热努塞尔数的平均值(Nu_(local))_(m)最高可为单一螺旋通道的2.51倍。考虑流量增加的影响,射流影响下的螺旋通道区域内综合强化传热因子PEC_(2)在1.05~1.21之间。
The purpose of this work is to explore fluid turbulent flow and heat transfer characteristics in the single rectangular helical duct with different aspect ratios of cross sectionγ.Furthermore,better heat transfer enhancement effect of the jet on the rectangular helical duct can be obtained.Computational fluid dynamic software is employed to research the turbulent flow fields,secondary flow fields and heat transfer characteristics both in the single rectangular helical duct and the helical duct mounted with a jet pipe.The jet pipe is mounted on the outer wall of the helical duct with a certain angle.Four aspect ratios of the cross sectionγas 0.625,1.1,1.6 and 2.5 respectively are selected for the rectangular helical duct.The results show that with the same cross-section area and flow rate,a four-vortex structure of the secondary flow can be found only in the helical duct atγ≥1.6 under high Reynolds number.Secondary flow pattern under other conditions is a two-vortex structure in the studied range.For a single helical channel,the larger theγvalue is,the smaller the flow resistance is and the worse the heat transfer performance is.Heat transfer capacities of the four walls on the rectangular cross section are all improved after the jet is added to the helical duct.The larger theγvalue is,the more significant heat transfer enhancement effect of jet can be obtained.The average value of the local Nusselt number on the heated wall(Nu_(local))_(m) can be up to 2.51 times than that of a single helical duct whenγ=2.5 and the ratio of jet velocity to the mainstream velocityε_(j)=3.55.The comprehensive enhanced heat transfer factor PEC_(2) of the helical duct area under the influence of the jet is between 1.05~1.21 when the influence of the increase of jet flow rate is considered.
作者
李雅侠
许鹏宇
韩泽民
李运杭
崔峰源
张静
Yaxia LI;Pengyu XU;Zemin HAN;Yunhang LI;Fengyuan CUI;Jing ZHANG(School of Mechanical and Power Engineering,Shenyang University of Chemical Technology,Shenyang,Liaoning 110142,China)
出处
《过程工程学报》
CAS
CSCD
北大核心
2022年第5期612-621,共10页
The Chinese Journal of Process Engineering
基金
国家自然科学基金资助项目(编号:51506133)
辽宁省教育厅研究项目(编号:LJ2020037)
辽宁省大学生创新创业项目国家级项目(编号:202010149019)。
关键词
螺旋通道
射流
换热系数
流动阻力
数值模拟
helical duct
jet
heat transfer coefficient
flow resistance
numerical simulation
