04. Boiling and Multi-Phase Flow

The principal aim of this study is to examine the behavior of single bubbles as they break up in a Venturi tube, where they split into microbubbles. It is essential to understand the pressure profile and how it affects bubble breakup to maximize these applications, and the suitable flow conditions are suggested in applications. This study employs both experimental and numerical methods to investigate bubble breakup dynamics. In an experiment, a syringe is used to inject gas into the Venturi tube, and high-speed cameras are used to observe the single bubble behavior that forms. To determine how the pressure profile throughout the Venturi tube affects bubble dynamics, measurements are made of it. To record pressure variations at different locations within the tube, different pressure points are used. The TPFIT code is used to numerically simulate the bubble breakup process and flow field. The simulations accurately represent the experimental setup, enabling a thorough analysis of pressure fluctuations and how they affect bubble breakage. The interface between the gas and liquid phases is tracked using the Volume-of-Fluid (VOF) approach, which gives a clear picture of the bubble deformation and breakdown process. The results show that bubble breakup is primarily governed by three mechanisms: rotation and fragmentation caused by instabilities and vortex forces; elongation and breakup due to shear and elongational forces; and, in some cases, explosion into multiple fragments, possibly because of pressure changes. To improve our comprehension of bubble dynamics and validate the numerical model, the outcomes of the two approaches are contrasted. The results of this study will be very useful in the wastewater treatment industry, aquaculture industry, agriculture industry, chemical processing industry, etc.