换热表面直接与间接测温的对比性实验研究

Comparative experiments of direct and indirect temperature-measuring methods on boiling heat transfer surfaces

进行了沸腾换热表面的间接测温与直接测温的对比性实验研究。以水和乙醇作工质 ,对大气压力下的池沸腾换热平表面 ,用间接测温法和直接测温法同时测量壁面过热度 ,对两种测温方法的结果进行了比较研究。同时 ,用直接测温法进行三种不同管径的光管沸腾试验 ,并把实验结果与 Rohsenow公式进行了比较。大量实验结果表明 ,在一定操作条件下 ,直接测温法测量沸腾换热表面过热度误差较小 ,是一种简便而又行之有效的方法。

A direct temperature-measuring method on a boiling surface was proposed and comparative experinents of direct and indirect temperature-measuring on boiling heat transfer surfaces was conducted. Experiments were carried out on a plate surface and smooth tubes with distilled water and ethanol at atmosphere pressure. For the experiments on the plate surface, the wall superheating was simultaneously measured by recognized 'indirect method' and the 'direct method'. The experiments show that the largest relative deviation between direct method and indirect method was less than 6.2%. For the boiling experiments on outside smooth tubes, the wall superheating degrees were measured by direct method, and these experimental results were compared with Rohsenow's formula. It shows that, under a specific condition, direct method is a simple and effective way to measure the wall superheating of boiling heat transfer surfaces. It is of great importance to experimental study of boiling heat transfer, especially to boiling experiments on outside tubes.