Passive scalar transfer rate at bubble interface in Carreau liquid in a transition regime

Identifier:  imarina:9246580

Handle: https://hdl.handle.net/20.500.11797/imarina9246580

Authors:  Kazemi, Koorosh; Vernet, Anton; Grau, Francesc X; Cito, Salvatore; Fabregat, Alexandre

Abstract:
The scalar transfer rate from a bubble to a quiescent fluid with Carreau rheological behavior is studied here with Bond and Galilei number values respectively equal to 30 and 2 and a non-dimensional inelastic time constant (λ) equal to 6. Under these conditions the bubble dynamics regime stays within the steady and oscillatory areas. Navier Stokes equations are solved numerically in a non-stationary three dimensional domain and are coupled to the mass transfer equation of a scalar. The effect of the Peclet number (Pe) and flow index (n) of the quiescent fluid on the Sherwood number is explored within the following range: 10<Pe<1000, and 0.3<n<1.7. We observed that the shear thinning rheology destabilizes the bubble flow dynamics from steady towards an oscillatory regime and increases transfer rates between the bubble and surrounding fluids. This trend became even more prominent as Pe increased. Our results are condensed into an empirical predictive correlation that outperforms previous similar correlations and can be used to estimate the heat and mass transfer rate at the bubble interface in a Carreau liquid in a transition regime at a specific Galilei and Bond numbers.