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ISSN Online: 2377-424X

International Heat Transfer Conference 12
August, 18-23, 2002, Grenoble, France

Experimental and numerical study of a liquid/gas flow freezing in a pipe: influence of the interfacial resistance

Get access (open in a dialog) DOI: 10.1615/IHTC12.2230
6 pages

Abstract

The freezing of a hot liquid and gas mixture injected into a cold pipe is investigated with BULLAGE experiments carried out in CEA-Grenoble, with liquid water and nitrogen gas. The void fraction increase influence on solidification dynamics is quantified. Firstly, the ejected mass is decreasing in a different way from what is expected from the mixture density decrease. Secondly, the time necessary to block the flow is clearly decreasing at high pressure gradient and slightly decreasing at low pressure gradient. The numerical analysis is performed with the SIMMER code. It describes, in an eulerian format, the freezing of a liquid and gas mixture, in a mechanistic way, solving mass, momentum, energy and interfacial area transport equations for each component. Experimentally observed tendencies are predicted, if the interface resistance between the wall and the crust in single-phase flows is correctly modelled. Typical two-phase flow effects, with velocity differences between the phases, are shown, which can not be represented with an homogeneous model. The numerical analysis allows to predict the experimental freezing mode, based on crust growth. It gives insights which can not be provided by the experimental data, about the pressure effect on freezing, which is relatively higher than the temperature effect at high void fractions.