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ISSN Online: 2377-424X

ISBN Print: 978-1-56700-474-8

ISBN Online: 978-1-56700-473-1

International Heat Transfer Conference 16
August, 10-15, 2018, Beijing, China

ENHANCED VOF-BASED DIRECT NUMERICAL SIMULATIONS OF SLUG FLOW BOILING WITHIN MICRO-CHANNELS WITH SMOOTH AND FINNED HEATED WALLS

Get access (open in a dialog) DOI: 10.1615/IHTC16.mpf.023596
pages 6503-6510

Abstract

Flow boiling in micro-channels constitutes an effective cooling method which has been proven experimentally to be able to remove significantly high heat fluxes, while keeping the component of interest at an appropriate operating temperature. Plenty of experimental works exist in literature so far, but appropriate models to predict flow boiling heat transfer are still lacking or they are based on unrealistic assumptions. In the present investigation, direct numerical simulations of vapour slug growth associated with flow boiling within micro-channels are performed, utilising an enhanced Volume of Fluid (VOF) based method that accounts for spurious currents reduction and phase-change. The effect of various micro-structured finned patterns in the heated wall of the channels is numerically investigated. The main aim is to give further insight on the effect of surface structuring on flow boiling in the slug flow regime. The utilised, enhanced VOF-based model is implemented in OpenFOAM CFD toolbox. Initially, comparison with literature available numerical results for a straight wall circular micro-channel is carried out. After the proposed comparison, different geometrical configurations of the heated part of the utilised channel are implemented, keeping the same operating and initial conditions. In more detail, various fin patterns of rectangular cross-section are introduced in the heated wall of the channel. The analysis of the results reveals in order to have an increase in the heat transfer coefficient an optimum geometric configuration is needed.