A Phenomenological Model for Boiling Heat Transfer and the Critical Heat Flux in Tubes Containing Twisted Tapes

New critical heat flux (CHF) and boiling heat transfer data were obtained in the subcooled and low quality regions using refrigerant 113. These data were obtained in a 0.61 cm round tube containing a twisted tape having a twist ratio of 6.25. The new CHF data, plus water data from the literature, were compared to a modified version of the CHF predictive model based on bubble crowding and coalescence in the bubbly layer [Weisman and Pei, Int. J. Heat Mass Transfer 26, 1463-1478 (1983), Weisman and Illeslamlou, Fusion Tech. 13, 654-659 (1988)]. Reasonably good predictions were obtained within the range of the model. It was also found that the Yang and Weisman [Int. J. Multiphase Flow 17, 77-94 (1991)] extension of the CHF model to boiling heat transfer held for swirling flow. © 1993