A CFD study of two-phase frozen flow of air/water through a safety relief valve

M Moftah.S. Moftah Alshaikh, William Dempster

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6 Citations (Scopus)
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The air-water two phase critical flows through a safety relief valve commonly used in the refrigeration industry is examined with particular emphasis on the prediction of the critical mass flowrates using CFD based approaches. The expansion of the gas through the valve and the associated acceleration is coupled to the liquid phase and results in changes to the velocity slip with the possibility of influencing the choking conditions and the magnitude of the critical mass flows. These conditions are poorly reported in the literature for safety valves. This paper presents a study where the ability of established two phase multi-dimensional modelling approaches to predict such conditions are investigated. Comparison with the simplified mixture model will show that this model tends to underestimate mass flowrates for medium to high liquid mass fraction. However, the two fluid model can adequately account for the thermal and mechanical non equilibrium for these complex flow conditions with the use of simplified droplet sizing rules.
Original languageEnglish
Pages (from-to)533-540
Number of pages11
JournalInternational Journal of Chemical Reactor Engineering
Issue number4
Early online date1 Dec 2015
Publication statusPublished - 30 Dec 2015
Event13th International Conference on Multiphase Flow in Industrial Plants, MFIP13 - Genoa, Sestri Levante, Italy
Duration: 16 Sept 201419 Sept 2014


  • two-phase flow
  • safety valves
  • CFD
  • experiments


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