微管道内壁面平均温度的实验测量

Experimental measurement of inner wall average temperature of microtubes

利用紫铜丝的电阻值与其表面温度的依变关系,实现对微管道内壁面平均温度的准确实验测量。不仅避免了传统的热电偶或热电阻接触式测量的缺点,同时为微尺度下介质传热特性的研究提供了一种有效的实验手段。应用该方法对内径为140.86μm的石英玻璃微管内蒸馏水强迫对流传热的Nu进行了研究,结果表明,微管道内的传热特性得到了一定的强化,并出现了转捩的提前,证明依托于电阻测温法的实验数据具有较可靠的参考价值。

The inner wall average temperature of the microtube was exactly measured according to the relationship between copper wire resistance and wall temperature. This method of wall temperature measurement has the advantage of non-contacting over the traditional temperature measurement by the thermocouple or heat resistance. At the same time, the method of wall temperature measurement was also an effective experimental means for the research of heat transfer characteristics of microtubes. Experiments were carried out to investigate forced convective heat transfer of distilled water flowing through quartz microtubes with inner diameter of 140.86 μm by the method of wall temperature measurement. The experimental results showed that the power of heat transfer of the microtube with inner diameter of 140.86μm is intensified and the transition from laminar to turbulent flow is earlier. The result corresponds with the predecessorst research results.