Abstract Molten salts have been proposed as heat transfer media due to their superior thermal performance at elevated temperatures. A number of heat transfer correlations have been proposed in the literature for molten salts without explicitly considering the radiative heat transfer effect in the salts, which may not be negligible. This study therefore attempts to (1) quantitatively analyze the convective and radiative heat transfer of molten salts using an overall heat transfer model that includes a radiative heat transfer model developed in this research and an existing conventional convective heat transfer model/correlation, such as the Sieder-Tate or Hausen correlation, and (2) provide rationale on under what conditions it is necessary to consider the radiative heat transfer effect in salts. A parametric study was performed using the radiative heat transfer model developed to investigate the effects of various input variables, including the tube size (inner diameter 5 to 50 mm), salt temperature (500°C to 1000°C), salt and wall temperature difference (5°C to 100°C), and salt absorption coefficient (1 to 100 m-1). Our study indicates that (1) the proposed overall heat transfer model reasonably predicts the salt convective and radiative heat transfer, (2) the radiative heat transfer is more important for laminar flows than transitional and turbulent flows, (3) the radiative heat transfer is more important in tubes of larger inner diameter, (4) the salt temperature affects the radiative heat transfer significantly while the temperature difference between the salt and wall has a slightly smaller effect for the range investigated (ΔT = 5°C to 100°C), and (5) the salt absorption coefficient significantly affects the salt radiative heat transfer.

中文翻译：

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熔盐中的对流和辐射传热

摘要 熔盐因其在高温下的优异热性能而被提议作为传热介质。文献中已经提出了许多熔盐的热传递相关性，但没有明确考虑盐中的辐射热传递效应，这可能是不可忽略的。因此，本研究试图 (1) 使用整体传热模型对熔盐的对流和辐射传热进行定量分析，该模型包括在本研究中开发的辐射传热模型和现有的常规对流传热模型/相关性，例如Sieder-Tate 或 Hausen 相关性，以及 (2) 提供了在什么条件下需要考虑盐中的辐射传热效应的基本原理。使用已开发的辐射传热模型进行参数研究，以研究各种输入变量的影响，包括管尺寸（内径 5 至 50 毫米）、盐温（500°C 至 1000°C）、盐度和壁温差（5°C 至 100°C）和盐吸收系数（1 至 100 m-1）。我们的研究表明：(1) 提出的整体传热模型合理地预测了盐对流和辐射传热，(2) 辐射传热对于层流比过渡流和湍流更重要，(3) 辐射传热是在较大内径的管子中更重要，