Gas bubble behaviour in liquid systems

© 1972 Dr. Robert David La NauzeThe formation phenomena of carbon-dioxide bubbling into water through 1/16”, 1/8” and 3/16” diameter orifices was recorded photographically for gas flow rates between 1 and 30 cm3/s for system pressures up to 300 psig. It was shown that for the same volumetric flow rate, determined at system conditions, increased system pressure causes smaller but more frequent bubbles to be formed. Bubbling at high mass flow rates is characterised by a large degree of interaction and coalescence near the orifice. A detailed analysis of mathematical models of the formation process was undertaken. This study highlighted fundamental inadequacies in an existing two stage growth model. A more realistic model of formation was developed which included terms for the inertia of the liquid surrounding the bubble and the gas momentum. Within the constraints of a single bubble analysis, the model shows good agreement with the experimental results for volume and flow rate and predicts the correct trend for frequency and pressure fluctuations across the orifice. The influence of liquid circulation on bubble growth at high system pressure is discussed and several theoretical approaches to the problem have been outlined