Shell-Side Flow Condensation Heat Transfer on Three-Dimensional Enhanced Surface

An experimental investigation of shell-side flow condensation was performed on three-dimensional surface enhanced tubes, including a herringbone micro-fin tube and a newly developed 1-EHT tube. An equivalent plain tube was also tested for performance comparison. All the test tubes had similar geometry parameters, i.e., inner diameter 11.43 mm and outer diameter 12.7 mm. The outer shell diameter was 24.5 mm with a wall thickness of 0.6 mm. Tests were conducted using R410A as the working fluid at a dew point of 45 °C. The mass flux range of 10–55 kg/(m2 · s) with an inlet quality of 0.8 and an outlet quality of 0.1. Experimental results showed that the plain tube exhibited a better condensation heat transfer performance. Moreover, the mass flux had a significant influence on the heat transfer coefficient for shell-side condensation. A new prediction model based on the Cavallini’s equation was developed to predict the condensing coefficient where the mean absolute error is less than 4%.