Multi-phase Interface Area Calculation Using Iso-Alpha Method

Jobin Raju, Bahram Haddadi Sisakht, Michael Harasek
One observes absorption phenomena when fluids of different nature come in contact with each other. During absorption, mass is transferred across the fluid-fluid interface in both directions via diffusion of species. Computational Fluid Dynamics (CFD) techniques can be suitably exploited to evaluate the extent of mass transfer and its visualization. The key parameters that influence a specific specie absorption rate are the area of interface and a driving force. Existing area calculation
more » ... calculation algorithms are either based on approximation techniques using the magnitude of gradient alpha (volume fraction) or geometrical methods. In the former method, the magnitude of the gradient alpha (volume fraction) can be suitably manipulated to approximate the area of the interface. In the latter method, the mesh cells are split into two to form an interface separating the different phases and then calculating the area of the polygonal interface. Current research focuses on accurateevaluation of the interface area between the two phases using a geometrical method-'Iso-Alpha' and its application on mass transfer simulations. The case of a rising bubble with mass transfer is considered for the current study. The total interface area of the bubble is calculated in every timestep using both methods for comparison. The magnitude of the interface area is validated against the area obtained from the post-processing utility – paraView. Subsequently, the species mass transfer rate is also compared using both area calculation methods. Mass transfer during bubbly flows is commonly observed in chemical and biological processes such as oxidation, fermentation, etc. Hence, a quantitative estimation of transferred mass is an important aspect in industrial-scale packed column bubble-liquid reactors and related chemical engineering applications.
doi:10.34726/hss.2021.86662 fatcat:pmipelh6o5dfbnlcookeuqc4z4