绝热圆腔内4根冷热微管阵列振动强化传热实验  

An experimental study of enforced heat transfer of four vibrated hot and cold microtube array in an adiabatic cylindrical enclosure

作　　者：李萌[1] 戴传山[1] 

机构地区：[1]天津大学机械工程学院中低温热能高效利用教育部重点实验室,天津300072

出　　处：《化工进展》2015年第6期1557-1563,1581,共8页Chemical Industry and Engineering Progress

基　　金：国家自然科学基金(51306130);国家重点基础研究发展计划(2011CB707203)项目

摘　　要：目前针对微细管管外同时有自然对流和周期横向振动存在情况下的混合对流问题鲜有研究。为了探究这种现象,进而开发一种新型的换热器,本文提出了一种由4根冷热微细管组成的微管阵列,将其平行放置于有中间流体的圆形腔体内,并对管束施加微小横向振动的混合对流传热机理进行研究。详细描述了实验系统及实验方法,以及后期对实验数据的处理方法,得到了传热Nu数随管间自然对流强度Ra数,强迫振动Rev数等量纲为1参数的变化曲线;揭示了该结构形式下传热特性随冷热管温差、振动频率、微管振幅等传热规律。结果表明,横向振动在小温差情况下传热强化效果更为明显。将本文实验数据与Lemlich单管振动实验中的数据进行对比,表明了振动对4根微管阵列的强化传热效果比单根管更明显。Little research has been done on mixed convection in the existence of natural convection and periodic vibration transversely around microtubes. In order to investigate this situation and develop a new-type heat exchanger,this research established horizontally parallelized hot and cold microtube array immersed in an adiabatic cylindrical enclosure,and investigated the heat transfer mechanism of mixed convection with transverse micro-vibration full of third fluid. The natural convection surrounding the hot and cold microtubes in the cylindrical enclosure was measured at various inlet temperatures and mass flowrates. In addition,experiment system,methods and data-processing were described in detail. The relationship of Nusselt number with Ra number and Rev number was obtained. These parameters disclosed the heat transfer law of heat-transfer characteristics at temperature differences between hot and cold tubes,vibration frequencies and microtube amplitudes. The results showed that the enhanced heat transfer was more remarkable at small temperature differences under vibrating conditions. The comparison between experimental data and Lemlich’s single tube vibration data showed heat transfer due to vibration with four microtubes was more distinct.

关 键 词：微管 振动 强化传热 微尺度 传热 对流 

分 类 号：TK123[动力工程及工程热物理—工程热物理]