Abstract Current mathematical models and numerical codes used for thermal–hydraulic analyses of forced-flow superconducting cables used in the fusion technology, such as, e.g. Cable-in-Conduit Conductors (CICCs), are typically 1D. They demand reliable constitutive expressions for the transverse momentum, energy and optionally also mass transport processes occurring between different parallel conductor components, in order to reliably simulate the behavior of any superconducting magnet design either at normal operating conditions or during a quench evolution. Energy transport processes can effectively be expressed using heat transfer coefficient (HTC) and the considered wetted perimeter/surface. Only few HTC correlations for flow in a CICC bundle have been proposed in the literature, but none of them is widely accepted for predictive use. As a result, in thermal-hydraulic studies of conductors designed for the EU-DEMO coils standard heat transfer correlations for flows in smooth tubes are utilized, although they do not seem very appropriate for CICCs. Systematic measurements of heat transfer coefficients in a CICC bundle should be conducted to provide an experimental database for further trials to develop a reliable predictive heat transfer correlation. In the present work we report the results of measurements of the steady-state HTC between a jacket wall and demineralised water flowing (i) in a smooth tube and (ii) in a CICC bundle of the reference sample (JT60-SA TF conductor). The measurements were carried out at the THETIS installation. We used four values of water inlet temperature, in the range 30–68 °C, and various mass flow rates, in the range 0.15 – 0.40 kg/s, to obtain the results in possibly wide range of Pr and Re numbers. The experimental values of HTC for CICC slightly increased with the mass flow rate from about 7500 to 9400 W/(m2∙K) in the considered Re range (890–3490) and were almost independent on temperature. The performed experiment was also simulated with the THEA code for additional validation of the obtained HTC values.

中文翻译：

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单通道 CICC 中的稳态横向传热

摘要 当前用于聚变技术中强制流动超导电缆的热-水力分析的数学模型和数值代码，例如电缆套管导体（CICC），通常是一维的。他们需要可靠的本构表达式来表示不同平行导体组件之间发生的横向动量、能量以及可选的质量传输过程，以便可靠地模拟任何超导磁体设计在正常工作条件下或失超演变期间的行为。能量传输过程可以使用传热系数 (HTC) 和所考虑的润湿周长/表面来有效表达。文献中仅提出了 CICC 束中流动的少数 HTC 相关性，但没有一个被广泛接受用于预测用途。因此，在为 EU-DEMO 线圈设计的导体的热工水力研究中，使用了光滑管中流动的标准传热相关性，尽管它们似乎不太适合 CICC。应进行 CICC 管束中传热系数的系统测量，以便为进一步试验提供实验数据库，以开发可靠的预测传热相关性。在目前的工作中，我们报告了夹套壁和软化水之间的稳态 HTC 的测量结果（i）在光滑管中和（ii）在参考样品的 CICC 束中（JT60-SA TF 导体） . 测量是在 THETIS 装置中进行的。我们使用了 30–68 °C 范围内的四个进水温度值和 0.15 – 0.40 kg/s 范围内的各种质量流量，以获得可能范围广泛的 Pr 和 Re 数的结果。在考虑的 Re 范围 (890-3490) 内，CICC 的 HTC 实验值随着质量流量从约 7500 到 9400 W/(m2∙K) 略有增加，并且几乎与温度无关。还使用 THEA 代码模拟了进行的实验，以进一步验证获得的 HTC 值。