AT-2805 -- Enhancement of Saturated Boiling Heat Transfer by Internally Finned Tubes PDF

The paper reports the results of an experimental investigation in which heat transfer and pressure drop data were taken during saturated flaw bni1ing of R-113 inside four vertical, electrically heated tubes. One tube was smooth, and the remaining three were internally finned with different diameters and fin geometries. The smooth tube was used as a basis for comparison with the data of finned tubes. Over the mass flux range tested, an enhancement in the heat transfer coefficient was obtained as high as 146 over the smooth tube results on a nominal area basis. Correlation equations are proposed for predicting the overall heat transfer coefficient and pressure drop during saturated boiling inside internally finned tubes.