Void fraction distributions in a kettle reboiler

The void fraction and pressure distribution in shell-side boiling have been experimentally investigated. These data were collected from a horizontal tube bundle test section capable of modeling a kettle reboiler and a submerged evaporator. Kettle reboiler void fraction and pressure distributions were investigated for heat fluxes of 10, 30, 50, and 70 kW/m(2). Void fractions in the kettle reboiler tend to increase rapidly with vertical position low in the tube bundle but may decrease somewhat in the upper regions. Relatively large vapor concentrations in the bundle's central regions were due to the strong recirculation of vapor from the upper portions of the bundles that reentered near the center, in addition to vertical vapor acceleration at the bundle exit. Horizontal void concentrations were found to be fairly uniform. Local pressure drops generally agreed with the flow patterns found by visual analysis. (C) Elsevier Science Inc., 1997.