Study on evaluation method of tube—fin thermal contact conductance

The thermal contact conductance (TCC) is one of the principal parameter in heat transfer mechanism of tube—fin heat exchangers. Because of the difficulties in experimental measurements, the tube—fin TCC has not been focused deeply. This article presents a novel method in evaluating the TCC of tube—fin heatexchanger. First, the tube—fin contact status is investigated with a finite-element model of tube expansion process. Distribution of contact pressure along the tube—fin interface is obtained from the simulation results. Then, experiments are carried out for the relationship between the contact pressure and the TCC. Combining the experiment result with the contact pressure distribution, the tube—fin TCC can be evaluated. Based on the method, effect of processing factors of the expansion forming process, such as expanding ratio and die geometry, are examined.