The Influence of Gas and Liquid Flow Rates on the Transient Bubble Characteristics in a Liquid Cross-Flow

The paper reports on an experimental study conducted to investigate the dynamics of gas bubbles when injected from an orifice that is subjected to a liquid cross-flow. The experiments were conducted over a range of gas and liquid flow rates and at various orientations of the liquid channel. An image processing algorithm was developed for the detection and characterization of the bubbles in both temporal and spatial coordinates. The transient behaviour of bubble dynamics at different channel orientations under different liquid and gas flow conditions are presented in the paper. Results show that the equivalent bubble diameter in the vertical plane decreased with increase in time as well as with increase in the gas-to-liquid velocity ratio. The channel inclination has no appreciable effect on the bubble diameter. The streamwise bubble velocity showed significant transient fluctuations, which diminished with an increase in the channel inclination angle. The fluctuations of the bubble vertical velocity were found to be unaffected by the channel inclination angle. The magnitudes of both streamwise and vertical velocities were influenced by the channel inclination, however, the trends were found to be opposite.