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This paper is the third and final report of a study on the augmentation of in-tube condensation. Experimental results are presented for condensation of R-113 in two tubes with helical repeated-rib internal roughness and for a third spirally fluted tube. The repeated-rib tubes increased average heat transfer coefficients about 80% above smooth tube values, while improvements in heat transfer coefficients for the spirally fluted tube were approximately 50% (maximum inside diameter basis). The pressure drop increase in both types of tubes was less than 50%. A correlation is developed for the repeated-rib tube data. The various augmented tubes considered in this study are compared by a standard performance evaluation criterion.

Citation: ASHRAE Transactions, Volume 87, Part 2, Cincinnati, Ohio