水平小通道内高温熔盐对流传热特性实验研究
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摘要
高温熔盐是一种新型的传热流体,在太阳能光热发电及熔盐堆等领域中有广泛的应用前景。该文搭建了一套小型高温熔盐流动传热实验装置,采用二元硝酸盐为介质,并开展了高温熔盐在内径2.0mm水平小圆管内的对流传热实验研究。讨论了热流密度和质量流速等参数对熔盐流动传热的影响,获取了Nu数随Re数的变化规律,并与经典的Gnielinski关联式进行了对比。结果显示,该经典公式的预测值小于实验值。根据实验数据拟合了新的熔盐流动传热关联式,预测误差在10%范围内。
High-temperature molten salt is a new type of heat transfer fluid, which has extensive application prosperity inthe field of solar thermal utilization, molten salt reactor, and so on. In this study, an experimental system is established for flowand heat transfer of high-temperature molten salt. The convection heat transfer characteristics of molten salt flowing in amini-tube with an inner diameter of 2.0 mm are studied. The effects of heat flux and mass flux on the heat transfer of molten saltare discussed. The variations of Nusselt number with Reynolds number are obtained, and are compared with classic empirical correlation. The results show that the predictions using Gnielinski correlation are relatively lower than the experimental data. Therefore, a new correlation is developed for heat transfer of molten salt in mini tube. The new correlation predicts the experimental data within an accuracy of 10%.
High-temperature molten salt is a new type of heat transfer fluid, which has extensive application prosperity inthe field of solar thermal utilization, molten salt reactor, and so on. In this study, an experimental system is established for flowand heat transfer of high-temperature molten salt. The convection heat transfer characteristics of molten salt flowing in amini-tube with an inner diameter of 2.0 mm are studied. The effects of heat flux and mass flux on the heat transfer of molten saltare discussed. The variations of Nusselt number with Reynolds number are obtained, and are compared with classic empirical correlation. The results show that the predictions using Gnielinski correlation are relatively lower than the experimental data. Therefore, a new correlation is developed for heat transfer of molten salt in mini tube. The new correlation predicts the experimental data within an accuracy of 10%.
引文
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[2]VIGNAROOBAN K,XU X,ARVAY A,et al.Heat transfer fluids for concentrating solar power systemsA review[J].Applied Energy,2015,146:383-396.
[3]刘斌,吴玉庭,马重芳,等.圆管内熔融盐强迫对流换热的实验研究[J].工程热物理学报,2010,31(10):1739-1742.LIU Bin,WU Yu-ting,MA Chong-fang,et al.Experimental study for forced convective heat transfer with molten salts in a circular tube[J].Journal of Engineering Thermophysics,2010,31(10):1739-1742.
[4]LIU B,WU Y T,MA C F,et al.Turbulent convective heat transfer with molten salt in a circular pipe[J].International Communications in Heat and Mass Transfer,2009,36(9):912-916.
[5]刘闪威,吴玉庭,崔武军,等.低熔点熔盐圆管内强迫对流换热[J].化工学报,2015,66(2):530-536.LIU Shan-wei,WU Yu-ting,CUI Wu-jun,et al.Forced convection heat transfer with low-melting point molten salt in circular pipe[J].CIESC Journal,2015,66(2):530-536.
[6]杨敏林,杨晓西,杨小平,等.高温高热流密度熔盐吸热管传热试验研究[J].华北电力大学学报(自然科学版),2009,36(1):50-52.YANG Min-lin,YANG Xiao-xi,YANG Xiao-ping,et al.Experimental heat transfer research on molten salt receiver tube of high temperature and high flux[J].Journal of North China Electric Power University,2009,36(1):50-52.
[7]何石泉,丁静,陆建峰,等.管外高温熔盐的流动换热特性[J].工程热物理学报,2013,34(1):103-105.HE Shi-quan,DING Jing,LU Jian-feng,et al.Convective heat transfer characteristics of high temperature molten salt outside tube[J].Journal of Engineering Thermophysics,2013,34(1):103-105.
[8]孙波,周金豪,佘长锋,等.高温熔盐在层流区的传热特性[J].核技术,2015,38(3):72-76.SUN Bo,ZHOU Jin-hao,SHE Chang-feng,et al.Heat transfer characteristics of high temperature[J].Nuclear Techniques,2015,38(3):72-76.
[9]CHEN Y S,ZHU H H,TIAN J,et al.Convective heat transfer characteristics in the laminar and transition region of molten salt in concentric tube[J].Applied Thermal Engineering,2017,117:682-688.
[10]KIM H,KIM H,LEE S,et al.A study on heat transfer characteristics of quinary molten salt mixture[J].International Journal of Heat and Mass Transfer,2018,127:465-472.
[11]董正方,顾卫国,张红霞,等.表面活性剂减阻流体传热与阻力关系试验研究[J].水动力学研究与进展,2006,21(4):494-498.DONG Zheng-fang,GU Wei-guo,ZHANG Hong-xia,et al.Experimental investigation on comparison of heat transfer and friction of drag reducing surfactant fluid[J].Journal of Hydrodynamics,2006,21(4):494-498.
[12]CHANG C,SCIACOVELLI A,WU Z,et al.Enhanced heat transfer in a parabolic trough solar receiver by inserting rods and using molten salt as heat transfer fluid[J].Applied Energy,2018,220:337-350.
[13]沈向阳,丁静,陆建峰,等.高温熔盐在螺旋槽管内流动与传热的数值模拟[J].石油机械,2010,38(7):4-7.SHEN Xiang-yang,DING Jing,LU Jian-feng,et al.An experimental study of the heat transmission characteristics of the high-temperature molten salt in the spirally corrugated tube[J].China Petroleum Machinery,2010,38(7):4-7.
[14]孙奉仲,张鸣远,黄新元,等.镍基渗层纵向翅片管的强化传热试验研究[J].水动力学研究与进展,2002,17(4):467-471.SUN Feng-zhong,ZHANG Ming-yuan,HUANGXin-yuan,et al.Experimental study of enhanced heat transfer with Ni-based implanted longitudinal finned tubes[J].Journal of Hydrodynamics,2002,17(4):467-471.
[15]EIAMSA-ARD S,WONGCHAREE K.Heat transfer characteristics in micro-fin tube equipped with double twisted tapes:Effect of twisted tape and micro-fin tube arrangements[J].Journal of Hydrodynamics,2013,25(2):205-214.
[16]WANG K,HE Y L,ZHU H H.Integration between supercritical CO2 Brayton cycles and molten salt solar power towers:A review and a comprehensive comparison of different cycle layouts[J].Applied Energy,2017,195:819-836.