Thermally controlled bubble collapse in binary solutions

This paper theoretically analyzes thermally controlled bubble collapse in b inary solutions. Using a finite difference approach with an adaptive grid, three aspects of bubble collapse are investigated: counter-diffusion, initi al bubble diameter, and absorber cooling rate. Results illustrate how count er-diffusion of the absorbent, acting to preserve the bubble life span, is offset by convective mass transfer arising from bubble interface motion. Pr edicted bubble mass transfer rates for an ammonia water system increase wit h the square of the bubble radius (diameters: 1.8-5.6 mm) and with increase d absorber cooling rates. Model predictions compare well with simple semi-e mpirical correlations for bubble heat and mass transfer coefficients. (C) 2 000 Elsevier Science Ltd. All rights reserved.