中雷诺数下叉排圆柱列流动特性的可视化实验
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摘要
为了研究叉排圆柱列的流动规律,针对本实验搭建了开式循坏水槽,并设计叉排管束实验模型,从而对以叉排形式分布的管束列的换热效果提供理论性指导。利用染色法及PIV技术对叉排圆柱列进行可视化实验研究。在确定横向及纵向间距的情况下改变雷诺数,以及在确定雷诺数及纵向间距的情况下改变横向间距,从而对叉排圆柱列的瞬时场及时均场进行实验研究。实验结果表明在一定的雷诺数下,横向间距足够小时,第二列圆柱具有整流作用。增加横向间距后,上游圆柱及下游圆柱尾流均有涡的形成及脱落。同时叉排圆柱列的分布具有加速作用。
In order to study the flow characteristics of the staggered tube bundle and provide theoretical guidance for heat transfer enhancement,the open cyclic water tunnel and experimental model of staggered tube bundle are designed. Visualization experiments are performed by using dyeing method and Particular Image Velocimetry(PIV)method. Instantaneous and mean flow field of staggered tube bundle are explored at different transverse spacing and Reynolds Number. The experimental results demonstrate that,when transverse spacing is small enough,no vortex forms behind upstream cylinders because of the rectification action of downstream cylinders. While increasing transverse spacing,vortex forms and sheds behind upstream cylinders and downstream cylinders. At the same time,the accelerating effect exists in staggered tube bundle.
In order to study the flow characteristics of the staggered tube bundle and provide theoretical guidance for heat transfer enhancement,the open cyclic water tunnel and experimental model of staggered tube bundle are designed. Visualization experiments are performed by using dyeing method and Particular Image Velocimetry(PIV)method. Instantaneous and mean flow field of staggered tube bundle are explored at different transverse spacing and Reynolds Number. The experimental results demonstrate that,when transverse spacing is small enough,no vortex forms behind upstream cylinders because of the rectification action of downstream cylinders. While increasing transverse spacing,vortex forms and sheds behind upstream cylinders and downstream cylinders. At the same time,the accelerating effect exists in staggered tube bundle.
引文
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[9]Zou Shuai,Zhou Jie,Xi Guan-nan.Visualization studys of the flow overdouble cylinders in tandem arrangement in the middle reynolds numberrange[C].Kyoto:Doshisha University,2016:55-60.
[10]齐鄂荣,卢炜娟,邱兰.应用PIV系统研究横流中水平方柱绕流旋涡特征[J].武汉大学学报,2007(1):18-24.(Qi E-rong,Lu Wei-juan,Qiu Lan.Research on vortices of cross flowpast a horizontal square cylinder by PIV system[J].Engineering Journalof Wuhan University,2007(1):18-24.)
[2]赵舟,周少东,袁银男.过渡流下管束的流动、传热特性研究—串列双圆柱流场研究[J].工程热物理学报,2012(12):2194-2196.(Zhao Zhou,Zhou Shao-dong,Yuan Yin-nan.Study on flow and heat tr-ansfer characteristics of tubes in transition flow-flow field of tandem cy-linders[J].Journal of Engineering Thermophysics,2012(12):2194-2196.)
[3]张振亚,王芳,肖庭庭.替代工质R32和R290的对比研究[J].流体机械,2014(5):74-77.(Zhang Zhen-ya,Wang Fang,Xiao Ting-ting.Comparative tests of alter-native refrigerants R32 and R290[J].Fluid Machinery,2014(5):74-77.)
[4]焦凤,邓先和,孙大力.管束排列及管间距对换热器传热性能的影响[J].石油学报:石油加工,2013(5):836-843.(Jiao Feng,Deng Xian-he,Sun Da-li.Effects of tube arrangements andlongitudinal tube spacing on heat transfer performance of heat exchanger[J].Acta Petrolei Sinica:Petroleum Processing Section,2013(5):836-843.)
[5]S. F. Yan,C. S. Cai,S. D. Zhou.Numerical study on characteristics offlow and thermal fields of offset cylinder arrays in the middle reynolds nu-mber range[C].8th International Symposium on Heat Transfer,Beijing,2012:111.
[6]Lee M,Kang T,Kim Y.Air-side heat transfer characteristics of spiral-type circular fin-tube heat exchangers[J].International Journal of Refr-igeration,2010(33):313-320.
[7]Lam K,Lin Y F,Zou L.Experimental study and large eddy simulation ofturbulent flow around tube bundles composed of wavy and circular cyl-inders[J].Heat and Fluid Flow,2010(31):32-44.
[8]闫世峰,蔡春森,周少东.过渡流下叉排圆柱列流动传热特性的研究[J].工程热物理学报,2013(10):1948-1951.(Yan Shi-feng,Cai Chun-sen,Zhou Shao-dong.Study on flow and heattransfer characteristics of offset cylinder arrays in transition flow[J].Jou-rnal of Engineering Thermophysics,2013(10):1948-1951.)
[9]Zou Shuai,Zhou Jie,Xi Guan-nan.Visualization studys of the flow overdouble cylinders in tandem arrangement in the middle reynolds numberrange[C].Kyoto:Doshisha University,2016:55-60.
[10]齐鄂荣,卢炜娟,邱兰.应用PIV系统研究横流中水平方柱绕流旋涡特征[J].武汉大学学报,2007(1):18-24.(Qi E-rong,Lu Wei-juan,Qiu Lan.Research on vortices of cross flowpast a horizontal square cylinder by PIV system[J].Engineering Journalof Wuhan University,2007(1):18-24.)