空气-石蜡直接接触换热特性实验研究  

Experimental study on air-paraffin direct contact heat transfer characteristics

作　　者：李晗 蒲文灏[1] 杨宁 毛衍钦 岳晨[1] 张琦[2] LI Han;PU Wenhao;YANG Ning;MAO Yanqin;YUE Chen;ZHANG Qi(College of Energy and Power Engineering,Nanjing University of Aeronautics and Astronautics,Aero-engine Thermal Environment and Structure Key Laboratory of Ministry of Industry and Information Technology,Nanjing 210016,Jiangsu,China;School of Energy and Mechanical Engineering,Nanjing Normal University,Nanjing 210042,Jiangsu,China)

机构地区：[1]南京航空航天大学能源与动力学院,航空发动机热环境与热结构工业和信息化部重点实验室,江苏南京210016 [2]南京师范大学能源与机械工程学院,江苏南京210042

出　　处：《化工学报》2018年第9期3792-3798,共7页CIESC Journal

基　　金：国家自然科学基金项目(51606105);江苏省自然科学基金项目(BK20130905);中央高校基本科研业务费专项资金项目(NS2017012)。

摘　　要：在间壁式换热器中石蜡因为其热导率低影响了蓄热系统的换热速率,采用石蜡与空气直接接触换热可大幅提高蓄热系统的换热速率。把常温的空气通过气体分布器注入熔融状态的石蜡(100~150℃)中,具体考察了表观气速、静液位高度和传热温差等参数对石蜡-空气鼓泡换热中体积传热系数与气含率的影响。实验结果表明,随着表观气速的增大,体积传热系数与气含率随之增大,并且对于气含率,在较低的表观气速下的增长速率更快;在实验条件下,增加静液位高度都只会导致体积传热系数与气含率的降低,而改变气液温差对体积传热系数的影响不甚明显。根据实验结果获得了石蜡与空气直接接触换热的体积Nusselt数经验关联式。Paraffin wax in the partition wall type heat exchanger encumbers the heat transfer rate of the system because of its low thermal conductivity.The heat exchange rate of the heat storage system can be greatly improved by direct heat exchange between paraffin and air.Paraffin wax and air were used to study the heat transfer characteristics of air-paraffin direct contact heat transfer.The air at room temperature was injected into hightemperature(100-150℃)liquid paraffin through a distributor.This work examines the effects of superficial gas velocity,static liquid height and heat exchange temperature difference on the volumetric heat transfer coefficient and gas holdup rate in paraffin-air bubble heat transfer system.The results show that the volumetric heat transfer coefficient and the gas hold up increase by increasing the superficial gas velocity,and,for gas holdup,the growth rate is faster at lower superficial gas velocity.Increasing the height of the static liquid height will only lead to a decrease in the volumetric heat transfer coefficient and the gas holdup in the experimental conditions,and the effects of changing the gas liquid temperature difference on the volumetric heat transfer coefficient is not obvious.In addition,these effects are formulated in forms of empirical equations.

关 键 词：鼓泡塔 气液两相流 气泡 直接接触换热 传热温差 体积传热系数 体积Nusselt数 

分 类 号：TK11.4[动力工程及工程热物理—热能工程]