ABSTRACT
The local heat transfer coefficient and pressure gradient have been studied for forced convective evaporation of R-12 in a horizontal, deep spirally fluted tube. Effects of local quality, mass flux, and heat flux were investigated. The reduced data clearly show nucleate boiling and bulk convective regimes at low and high qualities, respectively. For a performance evaluation, the data were compared to the Kandlikar (1989) correlation for a smooth tube with a diameter equivalent to the envelope diameter of the Turbotec tube. The results showed that the Turbotec tube has a heat transfer enhancement ranging from 1.8 to 2.7 in the nucleate regime, and a more substantial increase in the convective regime, with enhancements there ranging from 3.3 to 7.8. For a given mass flow rate and heat input, the pressure drop was found to be from 6 to 20 times as great as a smooth tube of equivalent envelope diameter and heated length.
