定温加热下微石英管内部换热特征的实验研究  

Experimental study on the heat transfer characteristic in quartz microtube under heating of constant temperature

作　　者：刘志刚[1] 王秀春[2] 律翠萍[3] 

机构地区：[1]山东省科学院能源研究所,济南250014 [2]河北工业大学能源与环境工程学院,天津300130 [3]北京工业大学传热强化与过程节能教育部重点实验室,北京100022

出　　处：《华中科技大学学报（自然科学版）》2006年第11期86-89,共4页Journal of Huazhong University of Science and Technology(Natural Science Edition)

摘　　要：以蒸馏水为工质，流过内径分别为242μm，315μm和520μm石英管，采用饱和水蒸气来加热石英管，实现定温加热以研究石英管内部的换热．根据饱和水蒸气的压力来确定石英管外壁的温度值，实现了定温加热与温度测量的同步．实验得到了雷诺数RP在100-6000变化时的努谢尔特数Nu，并与经典的层流、过渡流及紊流换热准则方程式进行了对比．实验结果表明，在Re较低时，微石英管内部的Nu低于常规经典的换热准则方程式的解，但RP增加到16001900时，微石英管内的Nu与过渡流准则方程式的解基本一致；当RP增加到3500～5000时，微石英管内部换热的Nu达到常规尺度下的紊流换热方程式的解．Experiments were carried out to investigate forced convective heat transfer of distilled water flowing through quartz microtubes with inner diameter of 242μm, 315μm and 520μm. The microtube was heated by saturationsteam to keep a constant temperature. The wall average temperature was obtained according to saturation pressure of stream and achieved the synchronization of heating and measuring temperature. As the Reynolds number varied in the range from 100 up to 6 000 and the Nusselt numbers were measured, correspondingly. The experimental results were compared with the classical convective heat transfer correlations in laminar, transitional and turbulent regimes for con- ventional tubes. The comparison results indicated that the Nusselt number may be less than the classical laminar correlations when the Reynolds number is lower. The Nusselt number quickly increased with increasing of the Reynolds number. As Reynolds number was larger than 1 600 - 1 900 and 3 500-5 000, the corresponding Nusselt number will reach the value of the transitional correlations or that of the turbulent correlations.

关 键 词：微石英管 微换热 蒸汽加热 努谢尔特数 

分 类 号：TK124[动力工程及工程热物理—工程热物理]