Abstract Fluid flow and heat transfer characteristics in packed beds are of importance in many fields of study. However, experimental characterization and model validation of the numerical methods used to study packed beds is difficult. Utilizing nuclear magnetic resonance (NMR), we present a novel approach to track the melt front (and thus melt temperature) in a non-isothermal packed bed. The approach tracks the melt front through packed beds of wax encapsulated phase change material (PCM) by taking advantage of the change in T 2 associated with phase change. Additionally, velocity maps of the flow in the pore space of the same packed bed sample are obtained. The approach uses the 1 H signal from the PCM packing and the 19 F signal from the flowing fluid to allow monitoring of both particle bed structure/phase and flow velocities in the same sample with the use of a dual tune coil. Together, this information can be used to probe the heat transfer characteristics of packed beds experimentally.

中文翻译：

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通过磁共振成像测量的相变材料填充床中的熔体前沿传播和速度分布

摘要 填充床中的流体流动和传热特性在许多研究领域都很重要。然而，用于研究填充床的数值方法的实验表征和模型验证是困难的。利用核磁共振 (NMR)，我们提出了一种新方法来跟踪非等温填充床中的熔体前沿（以及熔体温度）。该方法利用与相变相关的 T 2 变化，通过蜡包封相变材料 (PCM) 的填充床跟踪熔体前沿。此外，还可以获得相同填充床样品孔隙空间中流动的速度图。该方法使用来自 PCM 填料的 1 H 信号和来自流动流体的 19 F 信号，以允许使用双调谐线圈监测同一样品中的颗粒床结构/相和流速。总之，这些信息可用于通过实验探测填充床的传热特性。