矩形单元蓄热特性及结构优化  

Heat storage characteristic and structure optimum inrectangular unit

作　　者：周慧琳 邱燕[1] ZHOU Huilin;QIU Yan(College of Energy and Power Engineering,Shandong University,Ji’nan 250061,Shandong,China)

机构地区：[1]山东大学能源与动力工程学院,山东济南250061

出　　处：《储能科学与技术》2020年第4期1082-1090,共9页Energy Storage Science and Technology

基　　金：国家自然科学基金项目(51576115);国网山东省电力公司科技项目(52060616000L)。

摘　　要：利用FLUENT软件对矩形单元内石蜡的熔化过程进行了数值模拟,分别研究不同的矩形单元上部尺寸、不同壁面温度对单元内石蜡熔化过程的影响,通过非线性拟合获得了单元内液相分数β与无量纲数Fo、Ste、Ra的准则关系式,为优化矩形单元内PCM总体熔化速率提供了方案与依据。研究结果表明:在石蜡熔化过程中,自然对流作为主导传热方式的时间比例随矩形单元上部尺寸的增加先增大后减小;自然对流对传热的强化作用随矩形单元内上部尺寸增加而增大,但平均储热速率随单元内上部尺寸的增加先增大后减小直至趋于平稳,存在最优值;温差是影响PCM熔化的关键因素之一,将温差从43℃提高至53℃,再从53℃提高至63℃熔化时间分别缩短14.63%、24.26%不等。The melting process of paraffin wax in rectangular unit is simulated by using FLUENT software.The effects of different upper geometry sizes and different wall temperatures on the melting process of different rectangular units are studied separately.The criterion relations between the liquid fractionβand the dimensionless number Fo,Ste,and Ra are obtained by nonlinear fitting.The scheme and basis are provided for optimizing the overall melting rate of PCM(phase change material)in the rectangular unit.The results show that,during the paraffin melting process,the time proportion of natural convection as the dominant heat transfer method increases first and then decreases as the size of the upper part of the rectangular unit increases.The enhancement of heat transfer by natural convection increases with the increase of the unit upper size.However,the average heat storage rate first increases and then decreases with the increase of the upper size of the unit until it tends to be stable,and there is an optimal value.During the paraffin melting process,the time proportion of natural convection as the dominant heat transfer method increases first and then decreases as the size of the upper part of the rectangular unit increases.The temperature difference is one of the key factors affecting the melting of PCM.The temperature difference is increased from 43°C to 53°C,and then from 53°C to 63°C,as a consequence of this,the melting time is shortened by 14.63%and 24.26%respectively.

关 键 词：相变材料 强化传热 自然对流 优化 数值模拟 

分 类 号：TQ051.5[化学工程]