Forced Convection Boiling in Tubes

Publisher Website
Google Scholar
Abstract
Local heat transfer coefficients and pressure gradients have been measured for bulk boiling of water in forced flow (vertically upward) in round tubes with internal diameters ranging from 0.1162 to 0.4317 in., lengths of 15 to 40 in., heat fluxes of 6 × 104 to 1.45 × 106 Btu/hr ft2, mass fluxes of 49 to 911 lb/sec ft2, exit qualities of 5 to 57%, and at pressures ranging from 42 to 505 psia. The local heat transfer coefficients expressed in the form of the Nusselt number have been correlated in terms of Reynolds and Prandtl numbers and two dimensionless groups characterizing forced convection vaporization, the Lockhart-Martinelli parameter Xtt, and the “boiling number,” Bo = (q/A)/Ghfg. For large values of the latter, nucleate boiling predominates and the dependence of the heat transfer on Xtt is small. Conversely, at the small values of Bo, convective flow effects are dominant, and there is a strong dependence on Xtt.

This publication has 4 references indexed in Scilit: