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ISSN Online: 2688-7231

ISBN Online: 978-1-56700-478-6

Proceedings of the 24th National and 2nd International ISHMT-ASTFE Heat and Mass Transfer Conference (IHMTC-2017)
December, 27-30, 2017, BITS Pilani, Hyderabad, India

CIRCULATION WITHIN A RISING BUBBLE

Get access (open in a dialog) DOI: 10.1615/IHMTC-2017.3030
pages 2163-2169

Resumo

Fluid interfacial motion induced by surface tension plays a fundamental role in many natural and industrial phenomena. Due to this interfacial motion, circulations are present inside drops/bubbles moving through an immiscible fluid. The presence of internal circulation affects the resistance offered to the motion of the drop/bubble and the possible development of boundary layer around it. Study of this internal circulation is important in industrial applications such as extraction, where one phase is dispersed in another liquid phase, as the circulations within affect mass transfer between these two phases. In this study, 2D and axisymmetric CFD simulation of internal circulation within a spherical bubble (fluid 1) of 1 mm diameter, in an incompressible fluid environment (fluid 2) was done using ANSYS FLUENT. Here, the two-phase problem was decoupled into two single phase problems, one with fluid 1 and the other with fluid 2. Using shear and velocity boundary conditions from one single phase simulation in the other, the internal and external flow patterns were obtained and the velocity obtained at the interface was found to match with the value obtained analytically, for a range of Reynolds numbers from 0.1 to 40. The applicability of Oseen approximation for solid spheres at large Reynolds numbers was checked in this case and was found inappropriate for a fluid drop dispersed in another immiscible fluid.