用于小型冰蓄冷空调的水平螺旋盘管沸腾传热模拟
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摘要
随着国民经济持续、稳定、高速的发展和人民生活水平的不断提高,冬天需要热源、夏天需要冷源的空调技术使用愈来愈普遍。空调的广泛使用加大了对电力的需求,也是造成电网峰谷负荷差的主要原因之一,电力供应高峰不足而低谷过剩的矛盾随着经济和社会的发展而日益突出。把蓄冷技术应用到家用空调器等小型空调设备上,它们所起到的移峰填谷作用将是很可观的,有着很大的经济效益和社会效益。
在小型冰蓄冷空调系统中,两器(蒸发器与冷凝器)是主要的热交换设备,其中,蓄冰槽又是系统中的关键设备,它的结构直接影响到空调系统的工作效率。前人已经将直管和螺旋管进行了比较分析,结果表明:螺旋管是一种有效的传热强化管,换热性能优于直管;结构紧凑,在单位空间内可布置更大的换热面积。螺旋管内两相流除两相流本身的复杂性外,由于受离心力和扭转力的作用,比直管中的流动要复杂得多。
本文在理论分析的指导下,利用数值模拟方法,对水平螺旋盘管内制冷剂R134a的饱和沸腾进行了三维数值模拟。在热流密度一定的条件下,对不同的流动形式(曲率半径与螺旋管径的比值Dc/D)及不同的质量流量下流体的换热系数进行比较计算,并分析了沿流动方向气体含气率、流体温度、流体流速的变化规律。计算结果与理论分析的结果吻合较好。可为以后研究两相流动的饱和沸腾换热传热的研究及小型冰蓄冷空调蓄冰槽中蒸发管的设计提供参考。
With the sustaining, steady, high-speed development of national economy and the improvement of the living standard, it is popular to utilize air conditioner to supply heat in winter and cool in summer. The widely usage of AC which aggravate the burden of power grid is a main cause of the load difference between on-peaks and off-peaks. So, the contradiction between power supply on-peaks and off-peaks becomes increasingly prominent with the economic and social development. However, the application of cool storage technology in small-sized air conditioner, such as residential, will play a considerable role in economic and social benefits.
The evaporator and condenser are the main heat exchange devices in small-sized cool storage air conditioning. Ice container whose frame will affect the performance coefficient of air conditioner greatly is the key facility thereof. Some comparative experiments between straight tubes and helical tubes have been taken. It indicates that helical tube is a kind of more effective enhanced heat exchanger than straight tube. Besides, more heat exchange area can be disposed in constant space because of the compact framework. The two-phase flow is very complicated not only for the complication of itself, but also the effects of centrifugal force and torsion torque.
Based on the theory guidance, this paper presents a three-dimensional model for the saturated boiling flow of R134a in a helically coiled tube using the numerical simulation. In the condition of constant heat flux, I made a comparative computation of heat exchange coefficient in different flow forms and mass flow rates. In addition, it presents the analysis on the transformation rules of vapor volume fraction, fluid temperature and fluid velocity. The results are well closed to the theory analysis. Therefore, the results can be used as a reference both for the two-phase flow research on boiling heat transfer and the design for evaporating tubes within small-sized ice storage air conditioners.
在小型冰蓄冷空调系统中,两器(蒸发器与冷凝器)是主要的热交换设备,其中,蓄冰槽又是系统中的关键设备,它的结构直接影响到空调系统的工作效率。前人已经将直管和螺旋管进行了比较分析,结果表明:螺旋管是一种有效的传热强化管,换热性能优于直管;结构紧凑,在单位空间内可布置更大的换热面积。螺旋管内两相流除两相流本身的复杂性外,由于受离心力和扭转力的作用,比直管中的流动要复杂得多。
本文在理论分析的指导下,利用数值模拟方法,对水平螺旋盘管内制冷剂R134a的饱和沸腾进行了三维数值模拟。在热流密度一定的条件下,对不同的流动形式(曲率半径与螺旋管径的比值Dc/D)及不同的质量流量下流体的换热系数进行比较计算,并分析了沿流动方向气体含气率、流体温度、流体流速的变化规律。计算结果与理论分析的结果吻合较好。可为以后研究两相流动的饱和沸腾换热传热的研究及小型冰蓄冷空调蓄冰槽中蒸发管的设计提供参考。
With the sustaining, steady, high-speed development of national economy and the improvement of the living standard, it is popular to utilize air conditioner to supply heat in winter and cool in summer. The widely usage of AC which aggravate the burden of power grid is a main cause of the load difference between on-peaks and off-peaks. So, the contradiction between power supply on-peaks and off-peaks becomes increasingly prominent with the economic and social development. However, the application of cool storage technology in small-sized air conditioner, such as residential, will play a considerable role in economic and social benefits.
The evaporator and condenser are the main heat exchange devices in small-sized cool storage air conditioning. Ice container whose frame will affect the performance coefficient of air conditioner greatly is the key facility thereof. Some comparative experiments between straight tubes and helical tubes have been taken. It indicates that helical tube is a kind of more effective enhanced heat exchanger than straight tube. Besides, more heat exchange area can be disposed in constant space because of the compact framework. The two-phase flow is very complicated not only for the complication of itself, but also the effects of centrifugal force and torsion torque.
Based on the theory guidance, this paper presents a three-dimensional model for the saturated boiling flow of R134a in a helically coiled tube using the numerical simulation. In the condition of constant heat flux, I made a comparative computation of heat exchange coefficient in different flow forms and mass flow rates. In addition, it presents the analysis on the transformation rules of vapor volume fraction, fluid temperature and fluid velocity. The results are well closed to the theory analysis. Therefore, the results can be used as a reference both for the two-phase flow research on boiling heat transfer and the design for evaporating tubes within small-sized ice storage air conditioners.
引文
[1]吴喜平.蓄冷技术和蓄热电锅炉在空调中的应用.同济大学出版社, 2000
[2]江亿.我国建筑耗能状况及有效的节能途径.暖通空调, 2005(35):30~40
[3]周宏春.促进建筑节能的对策建议.决策咨询通讯, 2007(1):42~43
[4]北京东?西城试点居民分时电价.实行“一日三价”中国电力采购信息网
[5]翟超勤,江亿,夏建军.全国家用空调器年耗电量的估算.全国暖通空调制冷2000年学术年会论文集, 2000.10:54~58
[6]刘顺波.冰蓄冷柜式空调器技术.家用电器科技, 1998.6:12~14
[7]钱芳.家用中央空调增长快.厦门晚报. http://www.csnn.com.cn/20051/ca360597.htm
[8]尾花英朗.热交换器设计手册(下册).石油工业出版社, 1982
[9]林宗虎.气液两相流及沸腾传热.西安交通大学出版社, 2003
[10]方贵银.蓄能空调技术.机械工业出版社, 2006
[11] http://www.ice-energy.com/Default.aspx?tabid=163
[12]赵力.小型蓄冷空调性能的实验研究.暖通空调, 1999, 29(5)
[13]周晓棠,李吉生,赵庆珠.家用空调中冰蓄冷的应用及实验研究.制冷学报, 2001(3):1~4
[14]方贵银,徐锡斌.小型蓄冷空调系统研究.制冷, 2003(3):5~8
[15]孙勇军,王惠龄.小型家用冰蓄冷空调优化运行试验研究.制冷与空调, 2006(10):71~73
[16]蒋爱华.小型蓄冷空调的发展前景探讨.制冷与空调, 2001(8):14~16
[17]刘广海,丁力行,屈睿瑰.蓄冷空调小型化研究.制冷与空调, 2003(12):33~37
[18]巩学梅,何永红.户式蓄冷空调系统的应用前景.节能与环保, 2002(1):48~49
[19]董云达.户用式冰蓄冷空调移峰填谷作用及运行费用分析.制冷与空调, 2002(6):62~64
[20] Groeneveld D C,Doerffer S,Tain R M,Hammouda N,Cheng S C. Fluid-to FluidModeling of the Critical Heat Flux and Post-Dryout Heat Transfer in Experimental Heat Transfer. Fluid Mechanics and Thermodynamics. Diot M,Mayinger F,Celata G P.(Editors) 1997
[21] Owhadi A,Bell K J,Crain B. Forced Convection Boiling Inside Helically Coiled Tubes. Heat and Mass Transfer, 1986, 11:5~11
[22] Berthoud G,Jayanti S. Characteristics of Dryout in Helical Coils. Heat and Mass Transfer, 1990, 33:33~38
[23] Watanabe O,Heya N,Ohrni Y,Fujita H. Low-quality Dryout in Horizontal Helical Tubes. Heat Transfer Japanese Research, 1992, 21:15~21
[24] Feng Z P,Guo L J,Chen X J. Transient and Time-Averaged Boiling Heat Transfer of Oscillatory Two-Phase Flow in Helical Coils. Experimental Heat Transfer, 2001, 12:22~28
[25]白博峰,郭烈锦,陈学俊.热流密度对汽水两相流压力波动特性的影响.核动力工程, 2001, 22:1~6
[26]李隆键,辛明道.自然对流对螺旋管内湍流对流换热影响.大连理工大学学报, 2001(11):51~54
[27]李隆键,辛明道,崔文智.三维内肋螺旋管内强化换热实验.热能动力工程, 2004(5):32~37
[28]李隆键,崔文智,辛明道.螺旋管内单相及沸腾的强化换热与阻力特性实验.核动力工程, 2005(2):41~45
[29]徐雪琴,李美玲. R134a在水平高效强化蒸发管内流动沸腾传热特性的实验研究.能源研究与信息, 2005, 12(3):22~25
[30]来逢逢. R134a螺旋管内沸腾传热模拟研究: [硕士论文].山东大学图书馆, 2006
[31]崔文智,廖全,辛明道. R134a在螺旋管内的流动沸腾传热.重庆大学学报, 2001(7):11~15
[32]韩吉田.具有蒸气过热的R134a在螺旋管内凝结换热的实验研究.制冷学报, 2005(9):17~23
[33]韩吉田. R134a在三种不同放置方式螺旋管内凝结换热的实验研究.制冷学报, 2004(2):32~37
[34]叶水泉.冰蓄冷空调技术及其发展.中国科协2004年学术年会电力分会场暨中国电机工程学会2004年学术年会论文集海南2004:432～438
[35]陈学俊.两相流与传热(第1版).原子能出版社, 1991
[36]郭烈锦.两相与多相流动力学.西安交通大学出版社, 2002
[37] Alves G E. Chemical Engineering Progress. 1989, 50: 449~456
[38] Crawford T. Weisman J. Multiphase Flow, 1984, 10(3): 385~391
[39]王福军.计算流体动力学分析——CFD软件原理与应用.清华大学出版社, 2004
[40]韩占忠,王敬,兰小平. FLUENT流体工程仿真计算实例与应用.北京理工大学出版社, 2004
[41] FLUENT Inc. FLUENT 6.3 DOCUMENTATION
[42] Fluent Inc. Tutorial: Heat and Mass Transfer With the Mixture Model. 2002.5
[43]林宗虎,王栋,王树众等.近期多相流基础理论研究综述.西安交通大学学报, 2001(35):32~38
[44]林宗虎,王栋,王树众等.多相流的近期工程应用趋势.西安交通大学学报, 2001(35):25~31
[45] Wang S Z, Lin Z H, Liang Z P. et al. Flow patterns and their transition in vertical downward pipelines with very viscous liquid[A]. Proceedings Of the ASME Heat Transfer Division. Vol 3(c). Atlanta: ASME, 1996:52~59
[46] Groeneveld D C,Doerffer S,Tain R M,Hammouda N,Cheng S C. Fluid-to Fluid Modeling of the Critical Heat Flux and Post-Dryout Heat Transfer in Experimental Heat Transfer. Fluid Mechanics and Thermodynamics. Diot M,Mayinger F,Celata G P.(Editors) 1997
[47] Yang X, Two-phase flow dynamics simulations and modeling Ph.D dissertation, University of Birmingham, UK. 1996
[48] Lopez de Bertodano M, et al. Development of k-εmodel bubbly two-phase flow, J,Fluids Eng. 1994:36~42
[49]冯自平,郭烈锦,陈学俊.卧式螺旋管压力降脉动瞬态及时均传热特性研究.核科学与工程, 1998(3):5~9
[50] Kataoka I, Serizawa A. Basic equations of turbulence in gas-liquid two-phase flow.Int.J. Multiphase Flow, 1989:12~18
[51] Guo L J, Feng z p, Chen X J. Experimental investigation of forced convective boiling flow instabilities in horizontal helically coiled tubes. Int. J. Thermal and Fluid Flow. 1997:21~26
[52] F.P.Incropera, D.P.Dewitt, Fundamentals of Heat Transfer 2nd.Ed.John Wiley&Sons, 1982
[53]方贵银,邢琳,杨帆.蓄冷空调技术的现状及发展趋势.制冷与空调, 2006(2):1~6
[54] Snyder N W. Summary of conference on bubbly Dynamics and boiling heat transfer. JPL Memo 20~137, CIT, 1986
[55] Chisholm D. Two-phase Flow in Pipelines and Heat Exchangers, George Godwin, 1983
[56] Hewitt G F. Measurement of Two-phase Flow Parameters, Academic Press, 1988
[57] Guo L J, Feng z p, Chen X J. Pressure drop oscillation of steam-water two-phase flow in a helically coiled tube. Int. J. Heat and Mass Transfer. 2001:25~32
[2]江亿.我国建筑耗能状况及有效的节能途径.暖通空调, 2005(35):30~40
[3]周宏春.促进建筑节能的对策建议.决策咨询通讯, 2007(1):42~43
[4]北京东?西城试点居民分时电价.实行“一日三价”中国电力采购信息网
[5]翟超勤,江亿,夏建军.全国家用空调器年耗电量的估算.全国暖通空调制冷2000年学术年会论文集, 2000.10:54~58
[6]刘顺波.冰蓄冷柜式空调器技术.家用电器科技, 1998.6:12~14
[7]钱芳.家用中央空调增长快.厦门晚报. http://www.csnn.com.cn/20051/ca360597.htm
[8]尾花英朗.热交换器设计手册(下册).石油工业出版社, 1982
[9]林宗虎.气液两相流及沸腾传热.西安交通大学出版社, 2003
[10]方贵银.蓄能空调技术.机械工业出版社, 2006
[11] http://www.ice-energy.com/Default.aspx?tabid=163
[12]赵力.小型蓄冷空调性能的实验研究.暖通空调, 1999, 29(5)
[13]周晓棠,李吉生,赵庆珠.家用空调中冰蓄冷的应用及实验研究.制冷学报, 2001(3):1~4
[14]方贵银,徐锡斌.小型蓄冷空调系统研究.制冷, 2003(3):5~8
[15]孙勇军,王惠龄.小型家用冰蓄冷空调优化运行试验研究.制冷与空调, 2006(10):71~73
[16]蒋爱华.小型蓄冷空调的发展前景探讨.制冷与空调, 2001(8):14~16
[17]刘广海,丁力行,屈睿瑰.蓄冷空调小型化研究.制冷与空调, 2003(12):33~37
[18]巩学梅,何永红.户式蓄冷空调系统的应用前景.节能与环保, 2002(1):48~49
[19]董云达.户用式冰蓄冷空调移峰填谷作用及运行费用分析.制冷与空调, 2002(6):62~64
[20] Groeneveld D C,Doerffer S,Tain R M,Hammouda N,Cheng S C. Fluid-to FluidModeling of the Critical Heat Flux and Post-Dryout Heat Transfer in Experimental Heat Transfer. Fluid Mechanics and Thermodynamics. Diot M,Mayinger F,Celata G P.(Editors) 1997
[21] Owhadi A,Bell K J,Crain B. Forced Convection Boiling Inside Helically Coiled Tubes. Heat and Mass Transfer, 1986, 11:5~11
[22] Berthoud G,Jayanti S. Characteristics of Dryout in Helical Coils. Heat and Mass Transfer, 1990, 33:33~38
[23] Watanabe O,Heya N,Ohrni Y,Fujita H. Low-quality Dryout in Horizontal Helical Tubes. Heat Transfer Japanese Research, 1992, 21:15~21
[24] Feng Z P,Guo L J,Chen X J. Transient and Time-Averaged Boiling Heat Transfer of Oscillatory Two-Phase Flow in Helical Coils. Experimental Heat Transfer, 2001, 12:22~28
[25]白博峰,郭烈锦,陈学俊.热流密度对汽水两相流压力波动特性的影响.核动力工程, 2001, 22:1~6
[26]李隆键,辛明道.自然对流对螺旋管内湍流对流换热影响.大连理工大学学报, 2001(11):51~54
[27]李隆键,辛明道,崔文智.三维内肋螺旋管内强化换热实验.热能动力工程, 2004(5):32~37
[28]李隆键,崔文智,辛明道.螺旋管内单相及沸腾的强化换热与阻力特性实验.核动力工程, 2005(2):41~45
[29]徐雪琴,李美玲. R134a在水平高效强化蒸发管内流动沸腾传热特性的实验研究.能源研究与信息, 2005, 12(3):22~25
[30]来逢逢. R134a螺旋管内沸腾传热模拟研究: [硕士论文].山东大学图书馆, 2006
[31]崔文智,廖全,辛明道. R134a在螺旋管内的流动沸腾传热.重庆大学学报, 2001(7):11~15
[32]韩吉田.具有蒸气过热的R134a在螺旋管内凝结换热的实验研究.制冷学报, 2005(9):17~23
[33]韩吉田. R134a在三种不同放置方式螺旋管内凝结换热的实验研究.制冷学报, 2004(2):32~37
[34]叶水泉.冰蓄冷空调技术及其发展.中国科协2004年学术年会电力分会场暨中国电机工程学会2004年学术年会论文集海南2004:432～438
[35]陈学俊.两相流与传热(第1版).原子能出版社, 1991
[36]郭烈锦.两相与多相流动力学.西安交通大学出版社, 2002
[37] Alves G E. Chemical Engineering Progress. 1989, 50: 449~456
[38] Crawford T. Weisman J. Multiphase Flow, 1984, 10(3): 385~391
[39]王福军.计算流体动力学分析——CFD软件原理与应用.清华大学出版社, 2004
[40]韩占忠,王敬,兰小平. FLUENT流体工程仿真计算实例与应用.北京理工大学出版社, 2004
[41] FLUENT Inc. FLUENT 6.3 DOCUMENTATION
[42] Fluent Inc. Tutorial: Heat and Mass Transfer With the Mixture Model. 2002.5
[43]林宗虎,王栋,王树众等.近期多相流基础理论研究综述.西安交通大学学报, 2001(35):32~38
[44]林宗虎,王栋,王树众等.多相流的近期工程应用趋势.西安交通大学学报, 2001(35):25~31
[45] Wang S Z, Lin Z H, Liang Z P. et al. Flow patterns and their transition in vertical downward pipelines with very viscous liquid[A]. Proceedings Of the ASME Heat Transfer Division. Vol 3(c). Atlanta: ASME, 1996:52~59
[46] Groeneveld D C,Doerffer S,Tain R M,Hammouda N,Cheng S C. Fluid-to Fluid Modeling of the Critical Heat Flux and Post-Dryout Heat Transfer in Experimental Heat Transfer. Fluid Mechanics and Thermodynamics. Diot M,Mayinger F,Celata G P.(Editors) 1997
[47] Yang X, Two-phase flow dynamics simulations and modeling Ph.D dissertation, University of Birmingham, UK. 1996
[48] Lopez de Bertodano M, et al. Development of k-εmodel bubbly two-phase flow, J,Fluids Eng. 1994:36~42
[49]冯自平,郭烈锦,陈学俊.卧式螺旋管压力降脉动瞬态及时均传热特性研究.核科学与工程, 1998(3):5~9
[50] Kataoka I, Serizawa A. Basic equations of turbulence in gas-liquid two-phase flow.Int.J. Multiphase Flow, 1989:12~18
[51] Guo L J, Feng z p, Chen X J. Experimental investigation of forced convective boiling flow instabilities in horizontal helically coiled tubes. Int. J. Thermal and Fluid Flow. 1997:21~26
[52] F.P.Incropera, D.P.Dewitt, Fundamentals of Heat Transfer 2nd.Ed.John Wiley&Sons, 1982
[53]方贵银,邢琳,杨帆.蓄冷空调技术的现状及发展趋势.制冷与空调, 2006(2):1~6
[54] Snyder N W. Summary of conference on bubbly Dynamics and boiling heat transfer. JPL Memo 20~137, CIT, 1986
[55] Chisholm D. Two-phase Flow in Pipelines and Heat Exchangers, George Godwin, 1983
[56] Hewitt G F. Measurement of Two-phase Flow Parameters, Academic Press, 1988
[57] Guo L J, Feng z p, Chen X J. Pressure drop oscillation of steam-water two-phase flow in a helically coiled tube. Int. J. Heat and Mass Transfer. 2001:25~32