Overview of possible two-phase flow models

HFM is applied to a system in which the liquid is volatile, then it assumes a high degree of non-equilibrium since the model does not account for any flashing and the flow could be greatly overestimated. The model is therefore not recommended for relief sizing for tempered systems.  

HFM (see above). It introduces a number of simplifying assumptions but is convenient when applicable because it does not require a computer code for its evaluation. It is described in detail in Annex 8. 

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