相变蓄热材料对蓄热水箱分层特性的影响  

Effect of phase change heat storage materials on thermal stratification property of heat storage water tank

作　　者：仵凡 张华[1] 王子龙[1] 秦延斌 WU Fan;ZHANG Hua;WANG Zilong;QIN Yanbin(School of Energy and Power Engineering,University of Shanghai for Science and Technology,Shanghai 200093,China)

机构地区：[1]上海理工大学能源与动力工程学院,上海200093

出　　处：《流体机械》2022年第2期20-27,共8页Fluid Machinery

基　　金：国家自然科学基金项目(51606126)。

摘　　要：为了研究相变蓄热材料对水箱热力学特性的影响,提出采用中低温相变材料三水合醋酸钠作为蓄热材料的立式太阳能相变蓄热水箱,研究在初始水温80℃、进水温度5℃的工况下的相变蓄热水箱的热力学特性,并基于ANSYS软件,建立了该水箱的数学模型,得到了释热过程中蓄热水箱的温度分布图。采用理查德森数分析法、混合数分析法以及填充效率分析法,综合对比和分析了相变蓄热球在水箱中的不同位置和相变蓄热水箱在进水流量分别为1,3,5,7,9 L/min时的热分层特性。结果表明,随着释热过程的进行,入口流量越小,热分层效果越好。PCM4,PCM3,PCM2和PCM1中等温面(303.15 K)和等温面(348.15 K)的间距分别为9.28,10.52,11.13,11.75 cm,表明蓄热水箱内冷热水的混合程度随着相变蓄热球位置升高而加强,即相变蓄热球越靠近蓄热水箱进口,斜温层厚度越小。In order to study the effect of phase change materials(PCMs)on the thermodynamic properties of water tanks,a vertical solar phase change thermal storage tank using sodium acetate trihydrate(SAT)with medium and low temperature as the PCM was proposed,the thermodynamic characteristics of the phase change thermal storage water tank were studied at the initial water temperature of 80℃and the inlet water temperature of 5℃,and based on ANSYS software,the mathematical model of the water tank was established,and the temperature distribution profile of the water storage tank in the process of heat releasing was obtained.The thermal stratification characteristics of the phase change thermal storage tank were compared and analyzed using Richardson number,MIX number and filling efficiency at different positions of PCM units in the tank and at inlet flow rates of 1,3,5,7 and 9 L/min,respectively.The results show that the smaller the inlet flow rate,the better the thermal stratification effect of the tank in the heat release process.The spacing of isothermal surfaces(303.15 K)and isothermal surfaces(348.15 K)in PCM4,PCM3,PCM2 and PCM1 is 9.28,10.52,11.13,11.75 cm respectively,indicating that the mixing degree of hot and cold water in the tank increases with the increase of the position of the PCM units,that is,the closer the PCM units are to the inlet of the tank,the smaller the thickness of the inclined layer.

关 键 词：相变材料 蓄热 热分层 填充效率 水箱 

分 类 号：TH134[机械工程—机械制造及自动化]