高效细薄膜蒸发器的实验研究
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摘要
随着自然资源的匮乏,全球正面临着越来越严重的能源危机。高效传热系统在提高能源利用率方面有着重要的作用,可广泛应用于航空航天、船舶、制冷等各类工业领域。在传热系统中,蒸发器是不可缺少的重要组成部分,因此,高效蒸发器的研究具有重要的经济效益和社会价值。
本文研发了一种新型的细薄膜蒸发器,利用细薄膜蒸发强化传热的特点提高蒸发器的效率。所研制蒸发器的蒸发管采用外部翅片、内部微沟槽的结构,通过微沟槽辅助形成细薄膜,提高传热系数。本文搭建了一套实验系统,以去离子水为工质,通过调节进液量、加热功率、系统压力等方法测试所研制蒸发器的传热性能。为了验证细薄膜蒸发器的性能,本文制作了一个相同规格的普通光管蒸发器,在相同工况条件下对两种蒸发器进行对比实验研究。通过对比研究,本文所研发的细薄膜蒸发器在各实验工况下的传热性能均优于普通光管蒸发器,其中在蒸发温度60℃工况时的功率可达750W,约是同工况下普通光管蒸发器的1.5倍。此外,工质在细薄膜蒸发器中蒸发段较长,整体过热度较小,蒸发较为充分。实验结果表明,采用微沟槽结构的细薄膜蒸发器能有效地提高传热效率,改善蒸发器的传热性能。本文中的研究有助于进一步了解细薄膜强化传热的机理,对高效蒸发器的设计研究有一定的指导意义。
As the storage of the energy and natural resources becoming less and less, the whole world is facing significantly serious energy crisis. For high-efficiency heat transfer systems, which have a high energy utilization rate, can be applied for various kinds of industrial productions as well as many fields such as aerospace, shipping industry and etc. And the evaporator is one important part of this system, thus, it is of great economic benefit and social value for researching high-efficiency evaporator.
An evaporator utilizing thin film evaporation is fabricated for improving the efficiency of the evaporator. Fins are installing the outside of the copper pipes of which have miro-grooves on the inside wall. The grooves are helpful for forming thin films and enhancing heat performance, making a higher heat transfer efficiency. An experiment system is set up for testing the thin film evaporator by adjusting the fluid amount, heating power and system pressure, with deionized water as the working fluid. A similar regular evaporator made of smooth copper pipes is also fabricated and tested in order to compare the heat performance with the former evaporator. It turns out that thin film evaporator has a better performance than regular evaporator at almost every working conditions, and the heat power reach to750W at the working temperature of60℃,almost1.5times the power of regular evaporator. And it is also found that working fluid evaporates more sufficiently and has a lower superheat than regular evaporator. So, this thin film evaporator using micro-groove can enhance the heat transfer efficiency and improve the heat transfer performance. This research is helpful for a better understanding of the mechanism of evaporating thin film, and also instructive to the design of high efficiency evaporator.
本文研发了一种新型的细薄膜蒸发器,利用细薄膜蒸发强化传热的特点提高蒸发器的效率。所研制蒸发器的蒸发管采用外部翅片、内部微沟槽的结构,通过微沟槽辅助形成细薄膜,提高传热系数。本文搭建了一套实验系统,以去离子水为工质,通过调节进液量、加热功率、系统压力等方法测试所研制蒸发器的传热性能。为了验证细薄膜蒸发器的性能,本文制作了一个相同规格的普通光管蒸发器,在相同工况条件下对两种蒸发器进行对比实验研究。通过对比研究,本文所研发的细薄膜蒸发器在各实验工况下的传热性能均优于普通光管蒸发器,其中在蒸发温度60℃工况时的功率可达750W,约是同工况下普通光管蒸发器的1.5倍。此外,工质在细薄膜蒸发器中蒸发段较长,整体过热度较小,蒸发较为充分。实验结果表明,采用微沟槽结构的细薄膜蒸发器能有效地提高传热效率,改善蒸发器的传热性能。本文中的研究有助于进一步了解细薄膜强化传热的机理,对高效蒸发器的设计研究有一定的指导意义。
As the storage of the energy and natural resources becoming less and less, the whole world is facing significantly serious energy crisis. For high-efficiency heat transfer systems, which have a high energy utilization rate, can be applied for various kinds of industrial productions as well as many fields such as aerospace, shipping industry and etc. And the evaporator is one important part of this system, thus, it is of great economic benefit and social value for researching high-efficiency evaporator.
An evaporator utilizing thin film evaporation is fabricated for improving the efficiency of the evaporator. Fins are installing the outside of the copper pipes of which have miro-grooves on the inside wall. The grooves are helpful for forming thin films and enhancing heat performance, making a higher heat transfer efficiency. An experiment system is set up for testing the thin film evaporator by adjusting the fluid amount, heating power and system pressure, with deionized water as the working fluid. A similar regular evaporator made of smooth copper pipes is also fabricated and tested in order to compare the heat performance with the former evaporator. It turns out that thin film evaporator has a better performance than regular evaporator at almost every working conditions, and the heat power reach to750W at the working temperature of60℃,almost1.5times the power of regular evaporator. And it is also found that working fluid evaporates more sufficiently and has a lower superheat than regular evaporator. So, this thin film evaporator using micro-groove can enhance the heat transfer efficiency and improve the heat transfer performance. This research is helpful for a better understanding of the mechanism of evaporating thin film, and also instructive to the design of high efficiency evaporator.
引文
[1]白泉.关于单位GDP能耗指标的再认识.中国能源.2011.33(3)：9-13.
[2]张珍花,王鹏.我国能源现状的思考与能源战略建议.煤炭经济研究.2008.10：4-7.
[3]张红生.节能减排低碳生活.江苏现代计量.2011.2：34-37.
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[7]B. V. Derjaguin. A theory of capillary condensation in the pores of sorbents and of other capillary phenomena taking into account the disjoining action of polymolecular liquid films. Acta Physicochim,1940,12 (2):181-200.
[8]B. V. Derjaguin, S. V. Nerpin, N. V. Churaykev. Effect of film transfers upon evaporating liquids. International Association of Testing and Research Laboratories for Materials and Structures.1965,29(1):93-98.
[9]M. Potash. Jr., P. C. Wayner. Jr. Evaporation from a two-dimensional extended Meniscus. Int. J.Heat Mass Trans.1972,15:1851-1863.
[10]M. Sujanani, P. C. Wayner. Jr. Transport processes and interfacial phenomena in an evaporating meniscus. Chem.Eng. Commun.1992,118:89-110.
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[13]Stephan.P.C, Busse. C. A. Analysis of the Heat-Transfer Coefficient of Grooved Heat Pipe Evaporator Walls. Int. J. Heat Mass Trans.1992,35(2):383-391.
[14]HaoWang, Suresh.V. Garimella, Jayathi. Y. Murthy. Characteristic of an Evaporating Thin Film in a Microchannel. Int.J.Heat Mass Trans.2007,50:3933-3942.
[15]Hao Wang, Suresh V. Garimella, Jayathi Y. Murthy. An analytical solution for the total heat transfer in the thin-film region of an evaporating meniscus. Int. J.Heat Mass Trans.2008,51:6317-6322.
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[18]S. J. S. Morris. The evaporating meniscus in a channel. Fluid Mech.2003,494:297-317.
[19]Jiapeng Yu, Hao Wang. A molecular dynamics investigation on evaporation of thin liquid films. Int. J.Heat Mass Trans.2012,55:1218-1225.
[20]白鹏飞.多孔型微细通道强化传热结构的制造及传热性能研究：博士学位论文.广州：华南理工大学,2010.
[21]郭朝红.矩形微槽横截面换热特性的分析.工程热物理学报.2011,32(7)：1169-1172.
[22]Lixin Cheng, Dieter Mewes. Review of two-phase flow and flow boiling of mixtures in small and mini channels. International Journal of Multiphase Flow.2006 (32) 183-207.
[23]Xuegong Hu, Dawei Tang. Experimental investigation on flow and thermal characteristics of a micro phase-change cooling system with a microgroove evaporator. Int. J. Thermal. Sci.2006,46:1163-1171.
[24]Z. Z. Xia, G.Z.Yang, R.Z.Wang. Capillary-assisted flow and evaporation inside circumferential rectangular micro groove. Int.J. Heat Mass Trans.2009,52:952-961.
[25]Hao Wang, Zhenhai Pan, Suresh V.Garimella. Numerical investigation of heat and mass transfer from an evaporating meniscus in a heated open groove. Int.J.Heat Mass Trans.2011,54:3015-3023.
[26]Hemanth K., Jayathi Y. Murthy, Suresh V. Garimella. Numerical investigation of an evaporating meniscus in a channel. Int. J. Heat Mass. Trans.2012,55:915-924.
[27]Jinliang Wang, Ivan Catton. Enhanced evaporation heat transfer in triangular grooves coverd with a thin fine porous layer. Applied Thermal Engineering.2001, 21:1721-1737.
[28]赵俊杰,彭晓峰,段远源.微细通道内蒸发薄液膜区壁面滑移及微流动特性.工程热物理学报.2009,30(7)：1171-1174.
[29]Junjie Zhao, Yuan-Yuan Duan, Xiao-Dong Wang et al. Effects of superheat and temperature-dependent thermophysical properties on evaporating thin liquid films in microchannels. Int.J. Heat Mass Trans.,2011,54:1259-1267.
[30]Shao-Wen Chen, Jui-Ching Hsieh, Cheng-Tai Chou et al. Experimental investigation and visualization on capillary and boiling limits of micro-grooves made by different processes. Sensors and Actuators A 2007,139:78-87.
[31]A. Mukherjee. Contribution of thin-film evaporation during flow boiling inside microchannels. Int. J. Thermal Sci.2009,48:2025-2035.
[32]赵娜,杜小泽,杨立军等.毛细微结构中延展薄液膜过渡区的蒸发特性.化工学报.2008,59(8)：1930-1935。
[33]张丽春,马同泽,葛新石.平而蒸发薄液膜的稳定性分析.中国科学技术大学学报.2002,32(5)：618-625.
[34]曲伟,马同泽,苗建印.微小空间薄液膜相变传热的微尺度效应.航天器工程.2004,13(2)：36-45.
[35]曲伟,马同泽.毛细管内薄液膜轮廓和传热特性研究.工程热物理学报.2001,22(1)：66-69.
[36]杜世元,赵耀华.薄液膜蒸发传热影响因素分析.化学工程.2011,39(4)：54-57.
[37]Ma. H. B., Peterson G. P. Experimental investigation of the thermal capillary limit of a novel micro heat pipe design,1997,Anonymous.
[38]端震,赵孝保,董庆.垂直矩形微槽群内部相变换热的实验研究.南京师范大学学报(工程技术版).2008,8(2)：32-35.
[39]孙中原.微小型槽道平板热管传热特性研究：硕十学位论文.南京：南京航空航天大学.2006.
[40]S. M. Demsky, H. B. Ma Thin Film Evaporation On A Curved Surface. Nanoscale and Microscale Thermophysical Engineering.2004,8 (3):285-299.
[41]Chen Li, G.P.Peterson, Ji Li et al. The Visualization of Thin Film Evaporation on Thin Micro Sintered Copper Mesh Screen. ASME Summer Heat Transfer Conference, 2008
[42]赵耀华,鹤田隆治,胡学功.毛细微槽内的相变传热的实验研究.工程热物理学报.2004,25(5)：816818.
[43]赵孝保,李蓓,刘志刚.竖直微槽的倾角对相变换热影响的研究.工程热物理学报.2008,29(4)：637-639.
[44]Plawsky J L, Ojha M, Chatterjee A, et al. Review of the effects of surface topography, surface chemistry, and fluid physics onevaporation at the contact line. Chem.Eng.Comm.2008,196:658-696.
[45]寇志海.蒸发薄液膜及新型微槽平板热管传热性能的研究：博士学位论文.大连：大连理工大学,2011.
[46]H. H.Sait, H. B. Ma. An Experimental Investigation of Thin Film Evaporation. Nanoscale and Microscale Thermophysical Engineering.2009, (13):218-227.
[47]刘训海,张华.工程计算中关于翅片效率的一个问题.制冷与空调.2008,8(2)：2528.
[48]汤勇,潘敏强,汤兴贤.表面热功能结构制造领域的发展及关键技术.中国表面工程.2010,23(1)：1-8。
[49]欧栋生,汤勇,万珍平等.微型直齿沟槽铜管充液旋压-多级拉拔复合成形.华南理工大学学报(自然科学版).2010,38(12)：14-19.
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[2]张珍花,王鹏.我国能源现状的思考与能源战略建议.煤炭经济研究.2008.10：4-7.
[3]张红生.节能减排低碳生活.江苏现代计量.2011.2：34-37.
[4]何强,杨启明.强化传热节能技术的研究.石油和化工节能.2007,(6)：11-14.
[5]钱颂文,朱冬生,李庆颂等.管式换热器强化传热技术.北京：化学工业出版社,2003.
[6]A. J. Jiao, H.B. Ma, J. K. Critser. Evaporation heat transfer characteristics of a grooved heat pipe with micro-trapezoidal grooves. International Journal of Heat and Mass Transfer.2007,50:2905-2911.
[7]B. V. Derjaguin. A theory of capillary condensation in the pores of sorbents and of other capillary phenomena taking into account the disjoining action of polymolecular liquid films. Acta Physicochim,1940,12 (2):181-200.
[8]B. V. Derjaguin, S. V. Nerpin, N. V. Churaykev. Effect of film transfers upon evaporating liquids. International Association of Testing and Research Laboratories for Materials and Structures.1965,29(1):93-98.
[9]M. Potash. Jr., P. C. Wayner. Jr. Evaporation from a two-dimensional extended Meniscus. Int. J.Heat Mass Trans.1972,15:1851-1863.
[10]M. Sujanani, P. C. Wayner. Jr. Transport processes and interfacial phenomena in an evaporating meniscus. Chem.Eng. Commun.1992,118:89-110.
[11]S. Dasgupta, J.A.Schonberg, P.C.Wayner. Jr. Investigation of an evaporating extended meniscus based on the augmented Young-Laplace equation. Heat Transfer. 1993,115:201-208.
[12]S. Dasgupta, I.Y. Kim, P. C. Wayner Jr. Use of the Kelvin-Clapeyron equation to model an evaporating curved micro film. Heat Trans.1994,116:1007-1015.
[13]Stephan.P.C, Busse. C. A. Analysis of the Heat-Transfer Coefficient of Grooved Heat Pipe Evaporator Walls. Int. J. Heat Mass Trans.1992,35(2):383-391.
[14]HaoWang, Suresh.V. Garimella, Jayathi. Y. Murthy. Characteristic of an Evaporating Thin Film in a Microchannel. Int.J.Heat Mass Trans.2007,50:3933-3942.
[15]Hao Wang, Suresh V. Garimella, Jayathi Y. Murthy. An analytical solution for the total heat transfer in the thin-film region of an evaporating meniscus. Int. J.Heat Mass Trans.2008,51:6317-6322.
[16]Q.He, K.P. Hallinan. A new particle image velocimetry technique for three dimensional full field fluid flow measurement in evaporating films. Therm. Fluid Sci.1998,17:230-237.
[17]C.Hoffman, P. Stephan. Microscale temperature measurement at an evaporating liquid meniscus. Therm. Fluid Sci.2002,26:157-162.
[18]S. J. S. Morris. The evaporating meniscus in a channel. Fluid Mech.2003,494:297-317.
[19]Jiapeng Yu, Hao Wang. A molecular dynamics investigation on evaporation of thin liquid films. Int. J.Heat Mass Trans.2012,55:1218-1225.
[20]白鹏飞.多孔型微细通道强化传热结构的制造及传热性能研究：博士学位论文.广州：华南理工大学,2010.
[21]郭朝红.矩形微槽横截面换热特性的分析.工程热物理学报.2011,32(7)：1169-1172.
[22]Lixin Cheng, Dieter Mewes. Review of two-phase flow and flow boiling of mixtures in small and mini channels. International Journal of Multiphase Flow.2006 (32) 183-207.
[23]Xuegong Hu, Dawei Tang. Experimental investigation on flow and thermal characteristics of a micro phase-change cooling system with a microgroove evaporator. Int. J. Thermal. Sci.2006,46:1163-1171.
[24]Z. Z. Xia, G.Z.Yang, R.Z.Wang. Capillary-assisted flow and evaporation inside circumferential rectangular micro groove. Int.J. Heat Mass Trans.2009,52:952-961.
[25]Hao Wang, Zhenhai Pan, Suresh V.Garimella. Numerical investigation of heat and mass transfer from an evaporating meniscus in a heated open groove. Int.J.Heat Mass Trans.2011,54:3015-3023.
[26]Hemanth K., Jayathi Y. Murthy, Suresh V. Garimella. Numerical investigation of an evaporating meniscus in a channel. Int. J. Heat Mass. Trans.2012,55:915-924.
[27]Jinliang Wang, Ivan Catton. Enhanced evaporation heat transfer in triangular grooves coverd with a thin fine porous layer. Applied Thermal Engineering.2001, 21:1721-1737.
[28]赵俊杰,彭晓峰,段远源.微细通道内蒸发薄液膜区壁面滑移及微流动特性.工程热物理学报.2009,30(7)：1171-1174.
[29]Junjie Zhao, Yuan-Yuan Duan, Xiao-Dong Wang et al. Effects of superheat and temperature-dependent thermophysical properties on evaporating thin liquid films in microchannels. Int.J. Heat Mass Trans.,2011,54:1259-1267.
[30]Shao-Wen Chen, Jui-Ching Hsieh, Cheng-Tai Chou et al. Experimental investigation and visualization on capillary and boiling limits of micro-grooves made by different processes. Sensors and Actuators A 2007,139:78-87.
[31]A. Mukherjee. Contribution of thin-film evaporation during flow boiling inside microchannels. Int. J. Thermal Sci.2009,48:2025-2035.
[32]赵娜,杜小泽,杨立军等.毛细微结构中延展薄液膜过渡区的蒸发特性.化工学报.2008,59(8)：1930-1935。
[33]张丽春,马同泽,葛新石.平而蒸发薄液膜的稳定性分析.中国科学技术大学学报.2002,32(5)：618-625.
[34]曲伟,马同泽,苗建印.微小空间薄液膜相变传热的微尺度效应.航天器工程.2004,13(2)：36-45.
[35]曲伟,马同泽.毛细管内薄液膜轮廓和传热特性研究.工程热物理学报.2001,22(1)：66-69.
[36]杜世元,赵耀华.薄液膜蒸发传热影响因素分析.化学工程.2011,39(4)：54-57.
[37]Ma. H. B., Peterson G. P. Experimental investigation of the thermal capillary limit of a novel micro heat pipe design,1997,Anonymous.
[38]端震,赵孝保,董庆.垂直矩形微槽群内部相变换热的实验研究.南京师范大学学报(工程技术版).2008,8(2)：32-35.
[39]孙中原.微小型槽道平板热管传热特性研究：硕十学位论文.南京：南京航空航天大学.2006.
[40]S. M. Demsky, H. B. Ma Thin Film Evaporation On A Curved Surface. Nanoscale and Microscale Thermophysical Engineering.2004,8 (3):285-299.
[41]Chen Li, G.P.Peterson, Ji Li et al. The Visualization of Thin Film Evaporation on Thin Micro Sintered Copper Mesh Screen. ASME Summer Heat Transfer Conference, 2008
[42]赵耀华,鹤田隆治,胡学功.毛细微槽内的相变传热的实验研究.工程热物理学报.2004,25(5)：816818.
[43]赵孝保,李蓓,刘志刚.竖直微槽的倾角对相变换热影响的研究.工程热物理学报.2008,29(4)：637-639.
[44]Plawsky J L, Ojha M, Chatterjee A, et al. Review of the effects of surface topography, surface chemistry, and fluid physics onevaporation at the contact line. Chem.Eng.Comm.2008,196:658-696.
[45]寇志海.蒸发薄液膜及新型微槽平板热管传热性能的研究：博士学位论文.大连：大连理工大学,2011.
[46]H. H.Sait, H. B. Ma. An Experimental Investigation of Thin Film Evaporation. Nanoscale and Microscale Thermophysical Engineering.2009, (13):218-227.
[47]刘训海,张华.工程计算中关于翅片效率的一个问题.制冷与空调.2008,8(2)：2528.
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