Titre/Title :
Some recent results about the simulation of two phase flows with heat and mass transfer.
Résumé/Abstract :
In many engineering applications, the working medium is made of two or more fluids, thus the modeling of multiphase flows is of primary importance. A major issue remains how modeling the interface between two fluids, with an accurate description of the heat and mass transfer between these two fluids. Several approaches in literatures are also focused on including an accurate modeling for the thermodynamic description.
Inaccurate physical models can degrade the accuracy of the numerical simulation. In fact, when complex fluids are considered, such as cryogenic and molecularly complex ones, the use of simple equations of state (EOS) or tuning parameters can produce imprecise estimation of the thermodynamic properties, thus leading to the deterioration of the numerical prediction.
In this presentation, some new ideas for modeling heat and mass transfer in cryogenic fluids and for including an accurate estimation of the thermodynamics in molecularly complex gases will be presented. First, the attention will be focused on a cryogenic cavitating flow, for highlighting the effect of the temperature drop, known as “thermal effect”, during the mass transfer. A convective heat transfer is supposed between the two phases and a parametric study is performed, where several values of the convective coefficient hb are considered. The importance of the choice of hb value for the correct prediction of the temperature drop in the cavitating region is then demonstrated.
The second part of the talk will be directed towards the simulation of compressible two-phase flows. The role of an accurate model for the heat and mass transfer, along
with a complex thermodynamic description, will be investigated. A formulation based on a five-equation model will be presented and applied to the simulation of some benchmarks test-cases.