微管内流动与换热实验研究与分析  

Experimental Study and Analysis About Flow and Heat Transfer in Micro-tubes

作　　者：赵孝保[1] 刘志刚[2] 李蓓[1] 

机构地区：[1]南京师范大学动力工程学院,江苏南京210042 [2]山东省科学院能源研究所,山东济南250014

出　　处：《南京师范大学学报（工程技术版）》2007年第1期27-31,共5页Journal of Nanjing Normal University(Engineering and Technology Edition)

基　　金：江苏省自然科学基金(BK2006222)资助项目

摘　　要：采用不同压力下的水蒸汽来加热微管,蒸馏水流过内径分别为215μm、322μm、530μm及765μm微管,实验同时测量了微管两端的压力降及流量.实验得到了Re数在100-7 000之间变化时的摩擦阻力系数f及Nu数,并与经典的流动阻力系数及经典层流、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数较低时,微管内部f值与经典的理论值基本相等,微管内部的Nu数略低于常规经典的换热准则方程式的解;在Re数增加到1 800-2 000时,f值偏离经典的层流解,但微管内的Nu数与过渡流准则方程式的解基本一致;当Re数增加到3 000-7 000左右时,f值达到或接近勃拉修斯解,管内部换热的Nu数达到常规尺度下的紊流换热方程式的解.[关键词]微管,摩擦系数。The steam with different pressures were used as heating sources to heat the micro-tubes and the distilled water, used as the working fluid, flowed through micro-tubes with inner diameters of 215 μm, 322 μm, 530 μm and 765 μm, respectively. At the same time, pressure drops and flow rates in micro-tubes were experimentally measured. As the Reynolds number varied in the range from 100 up to 7 000 in the experiments and the friction factor and the Nusseh number were obtained correspondingly. The experimental results were compared with the classical flow theories and the classical convective heat transfer correlations in laminar, transitional and turbulent regimes for conventional tubes. The compared results indicated that the values of the friction factors in micro-tubes were in rough agreement with those of the Poiseuille equations and the Nusselt number were slightly less than those of the classical laminar heat transfer correlations at a low Reynolds number. As Reynolds number was larger than 1 800 - 2 000, the values of the friction factor departs from those of the Poiseuille equations and the Nusselt number reached the values of the transitional heat transfer correlations. The values of the friction factors were approximately equal to or near those of the Blassius equation and the Nusselt numbers were larger than those of the classical turbulent correlations when Reynolds number reached 3 000 - 7 000.

关 键 词：微管 摩擦系数 努谢尔特数 

分 类 号：TK124[动力工程及工程热物理—工程热物理]