Investigation of bubble formation in high-temperature water and silicone oil under submerged orifice gas injection conditions

Abstract

In diverse disciplines such as chemical engineering, metallurgy, and environmental engineering, the formation of bubbles through submerged orifice gas injection bears significant implications. However, the disparate characteristics of liquid mediums, notably between volatile and non-volatile liquids, often pose challenges to the universal application of bubble dynamics research findings. To bridge this gap, physical experiments utilizes both volatile (water) and non-volatile (silicone oil) liquids, aiming to elucidate the behavior of bubble formation under high-temperature liquid conditions. Experimental outcomes revealed an inverse relationship between liquid temperature and bubble detachment diameter: in water, the diameter increased, whereas in silicone oil, it decreased. Detailed analysis showed a 4.4 % increase in water bubble diameter within a 20–50 °C range and a 33.3 % increase within a 20–90 °C range. Conversely, in silicone oil, the diameter decreased by approximately 12.5 % within the 20–90 °C range. Mechanistic insights, derived from numerical simulations and ideal gas theory, revealed that a 50 °C temperature change led to a 27.7 % increase in bubble detachment diameter due to water evaporation, a 5.4 % increase due to gas thermal expansion, and a 2.1 % decrease due to alterations in surface tension coefficient and viscosity. To further investigate the formation and temperature rise of bubbles under thermal coupling, numerical simulations were conducted to obtain the variations in relevant characteristic parameters. The study reveals a two-stage temperature increase within the bubble, providing theoretical insights for the investigation of bubble dynamics under multiple physical fields coupling conditions.