Numerical and experimental study on the solidification of PCM around a vertical axially finned isothermal cylinder
Numerical and experimental study on the solidification of PCM around a vertical axially finned isothermal cylinder
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DOI：
10.1016/s1359-4311(00)00002-8
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发表时间：
2001-01-01
影响因子：
6.4
通讯作者：
Modesto, MS
中科院分区：
文献类型：
--
作者：
Ismail, KAR;Alves, CLF;Modesto, MS
本文介绍了一个数值和实验研究的结果实现翅片管的目的，使用它们在蓄热系统。该模型基于纯传导传热机理、焓公式法和控制容积法。采用有限差分近似和交替方向格式离散基本方程及相应的边界条件和初始条件。通过与现有结果和作者实现的其他实验测量结果进行比较，验证了该模型。翅片数量、翅片长度、翅片厚度、过热度和环间距的纵横比影响完全凝固时间、凝固质量分数和总储能。结果证实了翅片在延迟相变过程中自然对流的不良影响的重要性。此外，本研究表明，强烈的影响，环形空间的大小，翅片的径向长度和翅片的数量对凝固的质量分数和时间的完全相变。根据实验观察和数值结果的趋势，一个金属管安装有四个或五个翅片的恒定厚度等于管壁厚度和径向长度约两倍的管直径应该是一个折衷的解决方案之间的效率，增加热流率和可用存储容量的损失。(C)2000爱思唯尔科技有限公司版权所有。
This paper presents the results of a numerical and experimental investigation realized on finned tubes with the objective of using them in thermal storage systems. The model is based upon the pure conduction mechanism of heat transfer, the enthalpy formulation approach and the control volume method. The finite difference approximation and the alternating direction scheme are used to discretize the basic equations and the associated boundary and initial conditions. The model was validated by comparison with available results and additional experimental measurements realized by the authors. The number of fins, fin length, fin thickness, the degree of super heat and the aspect ratio of the annular spacing are found to influence the time for complete solidification, solidified mass fraction and the total stored energy. The results confirm the importance of the fins in delaying the undesirable effects of natural convection during the phase change processes. Also, this study indicates the strong influence of the annular space size, the radial length of the fin and the number of fins on the solidified mass fraction and the time for complete phase change. Based upon experimental observations and the tendencies of the numerical results, a metallic tube fitted with four-five fins of constant thickness equal to the tube wall thickness and of radial length around twice the tube diameter should be a compromise solution between efficiency, increase in the heat flow rate and the loss of available storage capacity. (C) 2000 Elsevier Science Ltd. All rights reserved.