Abstract A novel validation experiment for the melting of a phase change material is presented. The goal is to measure phase state and velocities with high accuracy and resolution. The geometry and boundary conditions of the test section are the most generic found in latent heat storage systems: a phase change material is contained in a rectangular enclosure, where it is isothermally heated from two opposing vertical side walls. The enclosure has a height of 105 mm and a width and depth of 50 mm. The bottom, front and back sides are solid transparent walls and on top is a thin layer of air. Near-adiabatic boundary conditions are realized at the non-heated sides with a surrounding insulated air-filled chamber and an actively controlled trace heating system. In this study n-octadecane is used as the phase change material. During melting, the liquid phase fraction is measured with a shadowgraph technique and velocities due to natural convection in the liquid phase are measured with particle image velocimetry (PIV). Interior and boundary temperatures are measured with thermocouples to control and analyze boundary effects. A thorough error estimation is done for all the measured quantities. The main result is a comprehensive dataset of liquid phase fractions and velocities with high spatial and temporal resolutions. The liquid phase fraction is additionally measured for three different driving temperature differences and a scaling by dimensionless numbers is performed. This results in a correlation function for the liquid phase fraction that predicts similar melting processes and is valuable in system design and optimization.

中文翻译：

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在具有两个加热垂直侧的矩形外壳中熔化正十八烷期间具有高时间和空间分辨率的相态和速度测量

摘要 提出了一种新的相变材料熔化验证实验。目标是以高精度和分辨率测量相位状态和速度。测试部分的几何形状和边界条件是潜热存储系统中最常见的：相变材料包含在矩形外壳中，从两个相对的垂直侧壁对其进行等温加热。外壳的高度为 105 毫米，宽度和深度为 50 毫米。底部、正面和背面是坚固的透明墙，顶部是一层薄薄的空气。近绝热边界条件在非加热侧实现，周围有一个绝缘的充气室和一个主动控制的伴热系统。在本研究中，正十八烷用作相变材料。在熔化过程中，液相部分用阴影图技术测量，由于液相中的自然对流而产生的速度用粒子图像测速法 (PIV) 测量。使用热电偶测量内部和边界温度，以控制和分析边界效应。对所有测量量进行彻底的误差估计。主要结果是具有高空间和时间分辨率的液相分数和速度的综合数据集。针对三个不同的驱动温度差另外测量液相分数，并执行无量纲数的缩放。这导致液相分数的相关函数可以预测类似的熔化过程，并且在系统设计和优化中很有价值。