翅片管外相变材料熔化过程的数值模拟
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摘要
相变材料的低导热性阻碍了相变蓄热设备的传热过程.采用翅片管是目前提升相变蓄热器传热速率的主要方法.使用Fluent软件中的Solidification/Melting模型对翅片管外相变材料熔化过程进行数值模拟,得到固-液相界面随时间的变化.通过改变翅片的厚度、翅片间距等参数,分析了不同的翅片参数对熔化时间的影响.结果表明:翅片的导热系数对蓄热时间影响较小;在一定范围内增加翅片的厚度可以强化相变储热过程,之后继续加厚翅片对蓄热时间影响不大;翅片间距对蓄热时间影响显著,缩小间距能大幅度缩短蓄热时间.
The low thermal conductivity of phase change material(PCM) is the main resistance for heat transfer in latent storage system.The main way to increase the heat storage efficiency is to use finned tube.The numerical simulation of melting process for phase change material outside heating tube with fins was conducted to obtain the change rule of the solid-liquid interface with time.The effects of tube fin parameters of fin thickness and gap on melting time were analyzed.The results show that the overall thermal performance is markedly increased by decreasing the gap of fins,while increasing the fin thickness and conductivity has slight improvement.
The low thermal conductivity of phase change material(PCM) is the main resistance for heat transfer in latent storage system.The main way to increase the heat storage efficiency is to use finned tube.The numerical simulation of melting process for phase change material outside heating tube with fins was conducted to obtain the change rule of the solid-liquid interface with time.The effects of tube fin parameters of fin thickness and gap on melting time were analyzed.The results show that the overall thermal performance is markedly increased by decreasing the gap of fins,while increasing the fin thickness and conductivity has slight improvement.
引文
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[2]LOPEZ J P A,KUZNIK F,BAILLIS D,et al.Numerical modeling and experimental validation of a PCM to air heat exchanger[J].Energy&Buildings,2013,64(64):415-422.
[3]CABEZA L F,CASTELL A,BARRENECHE C,et al.Materials used as PCM in thermal energy storage in buildings:a review[J].Renewable&Sustainable Energy Reviews,2011,15(3):1675-1695.
[4]SOARES N,COSTA J J,GASPAR A R,et al.Review of passive PCM latent heat thermal energy storage systems towards buildings'energy efficiency[J].Energy&Buildings,2013,59:82-103.
[5]KUZNIK F,DAVID D,JOHANNES K,et al.A review on phase change materials integrated in building walls[J].Renewable and Sustainable Energy Reviews,2011,15(1):379-391.
[6]CHINTAKRINDA K,WEINSTEIN R D,FLEISCHER A S.A direct comparison of three different material enhancement methods on the transient thermal response of paraffin phase change material exposed to high heat fluxes[J].International Journal of Thermal Sciences,2011,50(9):1639-1647.
[7]ZHAO C Y,LU W,TIAN Y.Heat transfer enhancement for thermal energy storage using metal foams embedded within phase change materials(PCMs)[J].Solar Energy,2010,84(8):1402-1412.
[8]FUKAI J,KANOU M,KODAMA Y,et al.Thermal conductivity enhancement of energy storage media using carbon fibers[J].Energy Conversion and Management,2000,41(14):1543-1556.
[9]ZHONG Y,GUO Q,LI S,et al.Heat transfer enhancement of paraffin wax using graphite foam for thermal energy storage[J].Solar Energy Materials and Solar Cells,2010,94(6):1011-1014.
[10]李新国,李伟,郭英利.圆管外石蜡相变蓄热与释热实验研究[J].工程热物理学报,2009,30(7):1223-1225.LI X G,LI W,GUO Y L.Experimental study on the heat storage and heat release by paraffin phase change outside tube[J].Journal of Engineering Thermophysics,2009,30(7):1223-1225.(in Chinese)
[11]HENZE R H,HUMPHREY J A C.Enhanced heat conduction in phase-change thermal energy storage devices[J].International Journal of Heat&Mass Transfer,1981,24(3):459-474.