Abstract

An experimental investigation of shell-side flow condensation heat transfer was performed on advanced 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 of the test tubes have similar geometry parameters (inner diameter 11.43mm, outer diameter 12.7mm). Tests were conducted using R410A as the working fluid at a condensation saturation temperature of 45 °C, covering 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 exhibits a better condensation heat transfer performance when compared to the enhanced tubes. Moreover, the mass flux has a significant influence on the heat transfer coefficient for shell-side condensation: the condensation heat transfer coefficient of plain tube decreases when the refrigerant mass flux becomes larger, while the heat transfer coefficient of herringbone tube shows a non-monotonic trend and the heat transfer coefficient of the 1-EHT tube gets higher with increasing refrigerant mass flux. Besides, A new prediction model based on the Cavallini’s equation was developed to predict the condensing coefficient of the three test tubes, and the mean absolute error of the improved equations is less than 4%.

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