翅片管外有机工质TFE凝结换热特性研究

翅片管外有机工质换热特性（凝结换热系数及液膜热阻）影响冷凝器的换热性能。理论模型基于努谢尔修正膜理论,为提高计算精度,将翅片管沿管周向划分有限个微元角,建立各个微元角内翅片侧壁和翅片间基管处的层流膜状凝结换热模型,迭代求解各个微元角内的壁面温度,根据各微元角壁面与饱和蒸汽温差,推导翅壁面及翅间基管上的液膜热阻和换热量,最后求解管子平均换热系数。管壁温度随圆周角θ增大而减小;翅壁及基管上液膜热阻随圆周角θ增大而增大;基管上液膜热阻大于壁面上液膜热阻。与实验值比较,理论模型计算精度高于积分解法计算值。

Research on Condensation Heat Transfer Characteristics of Organic Working Substance TFE on Finned Tube

The condensation heat transfer characteristics（ condensation heat transfer coefficient and liquid film thermal resistance） of organic working substance TFE on a finned tube are the key factors influencing the chiller performance. This paper establishes the laminar filmwise condensation heat transfer model on finned flank and the channel between the fins of horizontal finned tube based on the Neusslt modified film theory. In order to improve calculation accuracy,the model depended on elemental calculation by dividing the tube wall into finite elements,solving the wall temperature in each element by iteration method,based on the temperature difference between the wall temperature and the saturated steam temperature in each element,deriving the liquid film thermal resistance and heat transfer on finned flank and the channel between fins,finally solving the average heat transfer coefficient.The wall temperature decreases versus θ increases,the liquid film thermal resistance on the wall and the channel between fins increasing along the θ increases,the liquid film thermal resistance on the channel between fins is greater than those on the wall. Compared with the experimental results,the calculation accuracy is greater than the integral method.