过渡流下叉排圆柱列的可视化实验研究（英文）
|
摘要
为了保证缩小管径后的换热器空气侧换热性能良好,研究过渡流下不同雷诺数(Re=120,150,200),不同横向间距(P_s=2D,3D,4D,5D,6D)的叉排圆柱列的流动特性,采用PIV二维粒子图像测速系统对过渡流下不同工况的叉排圆柱列进行可视化实验研究.结果表明,P_s及Re的变化对上游和下游圆柱的涡量场、速度相关量有不同的影响.Re一定时,随着P_s的增大,下游对上游的整流作用逐步削弱.P_s一定时,随着Re的增大,整流效果越来越不明显.Re一定时,每组P_s下的速度比值曲线都呈现出"速度恢复"现象.并且随着P_s的增加,上游圆柱对下游圆柱来流速度所起到的加速效果逐步加强.
The study attempted to provide theoretical reference for the design and optimization of compact heat exchanger by investigating the flow characteristics of the offset cylinder arrays in transitional flow state. The two-dimensional particle image velocimetry(PIV) was adopted in visualization experiments. This research mainly focuses on offset cylinder arrays models in different transverse spacing(P_s/D = 2, 3, 4, 5, 6) and different Reynolds number(Re = 120, 150, 200) in the condition that longitudinal spacing is particular(PT= 2. 5 D). The results show that Re and P_shave different impact on the flow characteristics of this model. With the increase of P_s, rectifying effect caused by the downstream cylinders gradually weakens in the case of constant Re. With the increase of Re,rectifying effect becomes weaker in the case of constant P_s. The acceleration effect strengthens firstly and then weakens in each P_sin the case of constant Re, which shows the characteristic of speed recovery. With the increase of P_s, the acceleration effect on downstream cylinders inflow velocity gradually strengthens.
The study attempted to provide theoretical reference for the design and optimization of compact heat exchanger by investigating the flow characteristics of the offset cylinder arrays in transitional flow state. The two-dimensional particle image velocimetry(PIV) was adopted in visualization experiments. This research mainly focuses on offset cylinder arrays models in different transverse spacing(P_s/D = 2, 3, 4, 5, 6) and different Reynolds number(Re = 120, 150, 200) in the condition that longitudinal spacing is particular(PT= 2. 5 D). The results show that Re and P_shave different impact on the flow characteristics of this model. With the increase of P_s, rectifying effect caused by the downstream cylinders gradually weakens in the case of constant Re. With the increase of Re,rectifying effect becomes weaker in the case of constant P_s. The acceleration effect strengthens firstly and then weakens in each P_sin the case of constant Re, which shows the characteristic of speed recovery. With the increase of P_s, the acceleration effect on downstream cylinders inflow velocity gradually strengthens.
引文
[1]JIAO F,DENG X H,SUN D L,et al.Effects of tube arrangements and longitudinal tube spacing on heat transfer performance of heat exchanger[J].Acta Petrolei Sinica(Petroleum Processing Section),2013,29(5):836-843.
[2]ZOU S,ZHOU J,XU J H,et al.Study of double periodic cylindrical heat transfer mechanism under tandem transition flow[J].Machinery Design and Manufacture,2016(8):207-210.
[3]ZHOU H,ZHOU S D,YUAN Y N,et al.Study on flow and heat transfer characteristics of tubes in transition flowflow field of tandem cylinders[J].Journal of Engineering Thermophysics,2012,33(12):2194-2196.
[4]WANG Y F,CHEN FU,LI G Z,et al.Large eddy simulation of flow around side-by-side circular cylinders at various spacing[J].Journal of Engineering Thermophysics,2013,34(11):2039-2042.
[5]FUJII M,FUJII T,NAGATA T.A numerical analysis of laminar flow and heat transfer of air in an in-line tube bank[J].Numerical Heat Transfer,1984,7(1):89-102.
[6]ZHANG X D,JIANG J L,JIA Y S,et al.Measurements of cylinder′s wake by PIV[J].Journal of Experiments in Fluid Mechanics,2005,19(2):74-78.
[7]TU C X,WANG H L,LIN J Z.Experimental research on the flow characteristics and vortex shedding in the flow around a circular cylinder[J].Journal of China Jiliang University,2008,19(2):98-102.
[8]ZHANG Y Y,XI G N.Study on flow and heat transfer characteristics of five offset cylinder arrays in transitional flow[J].China Sciencepaper,2016(11):1291-1294.
[9]YAN S F,CAI C S,ZHOU S D,et al.Study on flow and heat transfer characteristics of offset cylinder arrays in transition flow[J].Journal of Engineering Thermophysics,2013,34(10):1948-1951.
[10]LAM K,LIN Y F,ZOU L,et al.Experimental study and large eddy simulation of turbulent flow around tube bundles composed of wavy and circular cylinders[J].International Journal of Heat and Fluid Flow,2010,31(1):32-44.
[11]OUYANG X P,LIU N.Contrast study of heat transfer and resistance performance of plate fin heat exchangers with cross flow&direct flow[C]//Proceedings of the Annual Academic Year of Shanghai Institute of Refrigeration.Shanghai:Shanghai Institute of Refrigeration,2003:4.
[12]OSTANEK J K,THOLE K A.Wake development in staggered short cylinder arrays within a channel[J].Experiments in fluids,2012,53(3):673-697.
[2]ZOU S,ZHOU J,XU J H,et al.Study of double periodic cylindrical heat transfer mechanism under tandem transition flow[J].Machinery Design and Manufacture,2016(8):207-210.
[3]ZHOU H,ZHOU S D,YUAN Y N,et al.Study on flow and heat transfer characteristics of tubes in transition flowflow field of tandem cylinders[J].Journal of Engineering Thermophysics,2012,33(12):2194-2196.
[4]WANG Y F,CHEN FU,LI G Z,et al.Large eddy simulation of flow around side-by-side circular cylinders at various spacing[J].Journal of Engineering Thermophysics,2013,34(11):2039-2042.
[5]FUJII M,FUJII T,NAGATA T.A numerical analysis of laminar flow and heat transfer of air in an in-line tube bank[J].Numerical Heat Transfer,1984,7(1):89-102.
[6]ZHANG X D,JIANG J L,JIA Y S,et al.Measurements of cylinder′s wake by PIV[J].Journal of Experiments in Fluid Mechanics,2005,19(2):74-78.
[7]TU C X,WANG H L,LIN J Z.Experimental research on the flow characteristics and vortex shedding in the flow around a circular cylinder[J].Journal of China Jiliang University,2008,19(2):98-102.
[8]ZHANG Y Y,XI G N.Study on flow and heat transfer characteristics of five offset cylinder arrays in transitional flow[J].China Sciencepaper,2016(11):1291-1294.
[9]YAN S F,CAI C S,ZHOU S D,et al.Study on flow and heat transfer characteristics of offset cylinder arrays in transition flow[J].Journal of Engineering Thermophysics,2013,34(10):1948-1951.
[10]LAM K,LIN Y F,ZOU L,et al.Experimental study and large eddy simulation of turbulent flow around tube bundles composed of wavy and circular cylinders[J].International Journal of Heat and Fluid Flow,2010,31(1):32-44.
[11]OUYANG X P,LIU N.Contrast study of heat transfer and resistance performance of plate fin heat exchangers with cross flow&direct flow[C]//Proceedings of the Annual Academic Year of Shanghai Institute of Refrigeration.Shanghai:Shanghai Institute of Refrigeration,2003:4.
[12]OSTANEK J K,THOLE K A.Wake development in staggered short cylinder arrays within a channel[J].Experiments in fluids,2012,53(3):673-697.