滴形管凝结换热性能的实验研究

采用特殊的管子形状和表面是最为常用、有效的强化换热手段。该文以滴形管凝结换热作为研究对象，阐述了烟气中水蒸气凝结换热过程的特点及强化换热的条件。对液滴在圆管和滴管不同位置处的受力进行分析，说明不同管形对液膜层厚度的影响程度。通过回收天然气锅炉排烟余热实验，研究滴形管的凝结换热性能，分析影响换热性能的因素，并与圆形管进行比较。结果表明：烟气通过滴形换热管的压损小于圆管，温差大于圆管，冷却水温升高于圆管，换热系数高于圆管。采用滴形管对于强化凝结换热是一种行之有效的方法。

Experimental Study on the Performance of Condensation Heat Transfer With Drop-shaped Tubes

It’s the most common and useful way to enhance heat transfer by using specific external tube shape and surface. The objective of the research was the performance of condensation heat transfer of the drop-shaped tube. Characters of the water steam in flue gas condensation heat transfer and the conditions of enhancing heat transfer were elaborated. The droplets force analysis at different place both on the drop-shaped and on the cylindrical tubes were got, which showed that the different tube shape would affect the thickness of the liquid film layer. The experiments on recovering the residual heat of the flue gas from gas-fired boiler were performed to study the condensation performance of the drop-shaped tube. Comparing with the cylindrical tube, the factors which affected the performance of heat transfer were analyzed. The results show that the loss of pressure of the flue gas flowed through the drop-shaped tubes is less than those of the cylindrical tubes. The temperature grad is great than those of the cylindrical tubes and the temperature rising of the cooling water in the drop-shaped tubes is great than those of the cylindrical tubes, and the heat transfer ratio is also great than those of the cylindrical tubes. The drop-shaped tube is a useful method to enhance the condensation heat transfer.