Bubbles growing in supersaturated solutions at reduced gravity

Abstract

This work investigates bubbles growing in a liquid saturated with a dissolved gas when its temperature is locally raised above its saturation value, yet below boiling. Local supersaturation is realized by giving heat pulses of variable power and duration to a miniature heater. The experiments are conducted in a low-gravity environment to de-couple bubble growth from buoyancy effects. A diffusion model is formulated considering the spherical growth of an internally heated bubble inside a uniformly subcooled liquid. The simple case of an isothermal bubble growth is solved analytically and compared to measurements to gain some physical insight. Two distinct regions are identified in the measured bubble growth curves: the initial stages are satisfactorily described by a parabolic (diffusion) law, whereas the later stages are approximately linear. (C) 2004 American Institute of Chemical Engineers