Bubble Size Distribution in Decaying High Turbulence usingPopulation Balance Equation*

The population Balance equation (PBE) employed with Euler-Euler formulation available in Open-

Foam finite volume open source code is utilized to predict the bubble size distribution in the turbulent

flow similar with that of generated by a side-channel pump. The inlet boundary condition with moderate swirl, extremely high turbulent intensity, and Reynolds number of 10⁵ is applied as a priori in

a squar duct with 60 cm lenght. The volumetric air content is considered

as 2% air at inlet with the bubble size evenly distributed in which 50% of the bubbles are of 100 μm

in diameter using velocity group concept. Alternatively, the break-up and coalescence of the bubbles

are treated implicitly increasing the cost of the

computations as if the sizes are field-dependent, though.

The bubble-bubble interaction is an essence in industrial and natural processes . This research predicts coalescence dominated bubble size distribution

under a frequent industrial condition in the downstream of a pump posing unique challenges and

opportunities for studying bubble behavior and interactions. Despite the theoretical advancements, experimental validation under such extreme turbulence intensities remains

scarce. Therefore, our study includes experimental investigations to bridge this gap.

The PBE coupled with term which models the coalescence predicts the gas-liquid flows under

extreme condition tackling the efficiency and performance improvement in multi-phase systems of engineering and environmental applications.