Phase change materials (PCMs) are well accepted as excellent candidates for thermal energy storage and many other important applications. One of their main drawbacks is the poor thermal conductivity which impairs their thermal performance. Many methods were proposed to solve this problem among which fins and nano-PCMs occupy leading positions in terms of efficiency and reliability. In this paper a homebuilt numerical code is used to calculate and compare the numerical predictions of finned and finless tubes submersed in PCM and nano-PCM. For both finned and finless tubes it is found that the increase in the nanoparticles fraction increases the interface position and the interface velocity and decreases the time for complete phase change. For the case of finless tube the addition of 10% of Al₂O₃ nanoparticles to the PCM and comparing the results with the case of finless tube in pure PCM are found to increase the interface position by 25%. On the other hand, the addition of 10% Al₂O₃ nanoparticles to the four fins tube and comparing the results with the case finless tube in pure PCM are found to reduce the complete solidification time by 9.1%.

相变材料（PCM）是公认的热能存储和许多其他重要应用的理想选择。它们的主要缺点之一是导热性差，这损害了它们的热性能。为了解决这个问题，提出了许多方法，其中鳍片和纳米PCM在效率和可靠性方面占据领先地位。在本文中，使用自制的数值代码来计算和比较浸没在PCM和nano-PCM中的翅片管和无翅片管的数值预测。对于翅片管和无翅片管，都发现纳米颗粒分数的增加增加了界面位置和界面速度，并减少了完全相变的时间。对于无翅片管，添加10％的Al ₂ O ₃将纳米颗粒添加到PCM中，并将结果与​​纯PCM中的无翅管的情况进行比较，发现界面位置增加了25％。另一方面，发现在四翅片管中添加10％Al ₂ O ₃纳米颗粒并将结果与​​无翅管在纯PCM中的情况进行比较，可以将完全固化时间减少9.1％。