联箱式分离型热管实验研究
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摘要
联箱式分离型热管的多支管并联可能导致流量分配不均,造成部分管道干涸,降低换热效果。搭建了7根管道并联的U型联箱式分离型热管实验平台,以R134a为工质,在800～2 200 W加热功率下,分析热管高效工作的充液率上下限、最佳充液率、热管系统换热特性及管道流量分配。结果表明:热管在充液率为31%～46%时可正常工作,最佳充液率约为42%;确认了各换热支管出现的流量分配不均匀特征,最靠近入口的分支管换热性能最佳,第4～6根换热管流量分配最少、性能最差。
The parallel channels in manifold of separated gravity heat-pipe may have the problem of the uneven distribution of flow,which can even lead to dry pipe and reduce the heat transfer effect. A U-type separated gravity heat-pipe system with 7 parallel channels has been built,R134 a is chosen as the medium and the heating power is changing from 800 W to 2 200 W. The upper and lower limits of the liquid filling rate,the optimum liquid filling rate,the heat transfer characteristics of the heat pipe system and the distribution of the flow are studied. Results show that the heat pipe can work steadily with the liquid filling rate of 31% ～ 46% and the optimum liquid filling rate is about 42%,and the characteristics of uneven distribution of flow in channels have been confirmed. The tube1 has the best heat transfer efficiency,while the flow distribution and heat transfer performance in tubes 4 ～ 6 is not satisfactory.
The parallel channels in manifold of separated gravity heat-pipe may have the problem of the uneven distribution of flow,which can even lead to dry pipe and reduce the heat transfer effect. A U-type separated gravity heat-pipe system with 7 parallel channels has been built,R134 a is chosen as the medium and the heating power is changing from 800 W to 2 200 W. The upper and lower limits of the liquid filling rate,the optimum liquid filling rate,the heat transfer characteristics of the heat pipe system and the distribution of the flow are studied. Results show that the heat pipe can work steadily with the liquid filling rate of 31% ～ 46% and the optimum liquid filling rate is about 42%,and the characteristics of uneven distribution of flow in channels have been confirmed. The tube1 has the best heat transfer efficiency,while the flow distribution and heat transfer performance in tubes 4 ～ 6 is not satisfactory.
引文
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[2]徐宝全.水平并联管系统中的两相流流量分配特性研究[D].西安:西安交通大学,1992.XU Bao-quan.Study on the gas-liquid two-phase flow distribution characteristics of a horizontal parallel tube system[D].Xi’an:Journal of Xi’an Jiaotong University,1992.
[3]何嘉.多分支并联管道流量分配机理及算法的数值研究[D].兰州:兰州交通大学,2014.HE Jia.Numerical analysis of the flow distribution in multiple branches parallel-tube configuration[D].Lanzhou:Journal of Lanzhou Jiaotong University,2014.
[4]韦晓丽,缪正清.Z型和U型集箱并联管组流动特性的实验研究[J].动力工程学报,2008,28(4):514-518.WEI Xiao-li,MIU Zheng-qing.Experimental study of flow characteristics in parallel tube set systems with type-Z and type-U headers[J].Journa1 of Power Engineering,2008,28(4):514-518.
[5]庞力平.气液两相流联箱中流量分配的理论和实验研究[D].北京:华北电力大学,2010.PANG Li-ping.Theoretical and experimental investigation on flow distribution in gas-liquid two-phase flow manifold[D].Beijing:North China Electric Power University,2010.
[6]王妍,徐宝全,王树众,等.水平并联管系统中两相流流量分配特性的可视性研究[J].西安交通大学学报,1998(7):63-67.WANG Yan,XU Bao-quan,WANG Shu-zhong,et al.Visual experimental investigation of gas-liquid flow distribution characteristics of horizontal parallel tube system[J].Journal of Xi’an Jiaotong University,1998(7):63-67.
[7]朱众勇,庞力平,王祥雨.几何结构对径向引入集箱系统气液两相流量分配特性影响的实验研究[J].节能,2016,35(4):22-27.ZHU Zhong-yong,PANG Li-ping,WANG Xiang-yu.Experimental study on the effect of geometric structure on the gas-liquid two phase flow distribution characteristics of a radial flow collector system[J].Energy Saving,2016,35(4):22-27.
[8]OEVELEN T V,WEIBEL J A,GARIMELLA S V.Predicting twophase flow distribution and stability in systems with many parallel heated channels[J].International Journal of Heat and Mass Transter,2017,107:557-571.
[9]易冲冲,王文,王博杰,等.分离型热管单管回路传热特性实验研究[J].热能动力工程,2014,29(6):633-638.YI Chong-chong,WANG Wen,WANG Bo-jie,et al.Experimental study on heat transfer characteristics of separated single-pipe heatpipe[J].Journa1 of Engineering for the Thermal Energy and Power,2014,29(6):633-638.
[10]胡院林,王博杰,易冲冲,等.以R134a为工质的分离式热管换热性能分析[J].低温与超导,2014,42(12):1-5.HU Yuan-lin,WANG Bo-jie,YI Chong-chong,et al.Experimental research on heat transfer of separated heat pipe using R134a[J].Cryogenics&Superconductivity,2014,42(12):1-5.