Numerical simulation of time‐dependent heat and fluid flows inside and around single rising bubbles using a moving axisymmetric boundary‐fitted mesh system

Abstract

Purpose

This paper aims to develop a numerical method for analysing the time‐dependent conjugate heat and fluid flows inside and around single bubbles rising in a hot liquid.

Design/methodology/approach

The procedure combines the moving mesh method for flows in time‐dependent geometries and the zoned calculation algorithm for conjugate viscous flows. A moving axisymmetric boundary‐fitted mesh is used to track the deformable gas‐liquid interface, while conjugate flows in both gas and liquid sides are calculated by a two‐block zoned method. The interfacial stresses are employed to calculate the velocity value and to decide the time‐dependent bubble shape simultaneously. Governing equations for the rising velocity and acceleration of the bubble are derived according to the forces acting on the bubble.

Findings

A calculating procedure for time‐dependent conjugate heat and fluid flows inside and around a rising single bubble has been developed. The algorithm has been verified, and can be employed for further analysing heat, mass and momentum transfer phenomena and their relevant mechanisms.

Originality/value

The paper developed a method to obtain high fidelity results for the heat and fluid flow details in the vicinity of a time‐dependent moderately deformable rising bubble; the physically zero‐thickness of a gas‐liquid interface is guaranteed. The governing equations for the time‐dependent rising velocity and acceleration are derived.

Citation

Lai, H., Yan, Y. and Wu, K. (2007), "Numerical simulation of time‐dependent heat and fluid flows inside and around single rising bubbles using a moving axisymmetric boundary‐fitted mesh system", International Journal of Numerical Methods for Heat & Fluid Flow, Vol. 17 No. 4, pp. 418-438. https://doi.org/10.1108/09615530710739185