Numerical Simulation of Convective Heat Transfer of Slug Flow in Micro Tube

In this paper, direct numerical simulation of incompressible two-phase (air-water) flow for simulation of bubble motion and convective heat transfer in micro tube is presented. Micro tube radius is 10 µm. The interface between two-phase is tracked with Volume of Fluid (VOF) method with Continuous Surface Force (CSF) model which is implemented in OpenFOAM CFD package. For simulation of convective heat transfer, energy equation and periodic thermal boundary condition is implemented in this package. Newtonian flows are solved using a finite volume scheme based on PISO algorithm. Numerical simulation is done on axisymmetric domain with periodic boundary condition for different values of pressure gradient, void fraction, and bubble period. Mean pressure gradient is fixed for each simulation. The superficial Reynolds numbers of gas and liquid phases studied are 0.3 – 7 and 5 – 210, respectively. Numerical results are coincident with Serizawa regime map. In presence of gas bubble in liquid, Numerical simulations show local Nusselt number increases than pure liquid which is in the penalty of pressure drop.