Abstract

Temperature dependence of the thermal conductivity of liquid water is important in several engineering applications. This study reports experimental measurements of the thermal conductivity of water as a function of temperature. The transient hot-wire method is used for measurement of the thermal conductivity over the temperature range of 273–305 K at atmospheric pressure conditions. The experiments are carried out for a fixed current of 250 mA, and the resulting temperature rise for a platinum wire 9.53 cm long with a radius of 25 \(\mu\)m yields the thermal conductivity by means of the solution to the heat conduction equation for a continuous line source in an infinite medium. It is found that using the temperature-dependent coefficient of resistance of platinum wire is crucial in obtaining the correct variation of the thermal conductivity with temperature. A data reduction procedure is suggested for improvement of the accuracy of the reported values via identification of the onset of convection in the fluid. The specific contributions of this work include the extension of experimental results to lower temperatures in the vicinity of the freezing point of water. This study also provides systematic comparison of experimental and computational results, which helps understand the fluid flow and heat transfer characteristics in the vicinity of a line source embedded in an infinite fluid medium.

中文翻译：

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使用瞬态热线法对水的热导率的温度依赖性

摘要

液态水的热导率的温度依赖性在一些工程应用中很重要。这项研究报告了作为温度函数的水的热导率的实验测量值。瞬态热线法用于在大气压条件下测量 273–305 K 温度范围内的热导率。实验是在 250 mA 的固定电流下进行的，对于 9.53 cm 长、半径为 25 \(\mu\)的铂丝产生的温升 m 通过求解无限介质中连续线源的热传导方程得到热导率。发现使用铂丝的温度相关电阻系数对于获得正确的热导率随温度变化是至关重要的。建议采用数据缩减程序，通过识别流体中对流的开始来提高报告值的准确性。这项工作的具体贡献包括将实验结果扩展到水冰点附近的较低温度。本研究还提供了实验和计算结果的系统比较，