Validation of a CFD model of Taylor flow hydrodynamics and heat transfer

The growing importance of the Taylor flow regime in microchannel flow and heat transfer has led to the need for validated CFD models. Experimental data for Taylor flow of water/nitrogen and ethylene glycol/nitrogen in a 2 mm diameter channel having Reynolds numbers in the range 22-1189 and Capillary number of 0.003-0.160 are used to validate a CFD model developed in ANSYS Fluent. The model simulates two-dimensional, periodic flow and heat transfer in a unit cell (comprising a single bubble and its adjacent half slugs) in a frame of reference moving with the bubble. The simulation results show excellent agreement with the bubble shape, film thickness, bubble velocity and homogeneous void fraction. The above data and the pressure drop data are compared with the available correlations and are shown to agree well, linking the experimental data, CFD results and established correlations in one validation exercise. Heat transfer simulations also reproduce the data well with a maximum difference of 15% except for high Reynolds number cases (Re-TP > 951). It is shown that in this case the assumption of two-dimensional, axisymmetric flow is no longer valid. (C) 2011 Elsevier Ltd. All rights reserved.