# Numerical simulations

**Numerical simulations **

Numerical simulations consist of two parts. First, we will simulate the simple case of evaporation trough a flat-plate in order to estimate the thickness of the boundary layer. Then, we will treat the real problem of the BEI by simulating the evaporation inside the reservoir.

In fact, the numerical analysis of the reservoir evaporation will be splitted in three parts. First a hydraulic study will be done on the fuel recuparator using the solver simpleFoam from OpenFoam. Then OpenFoam will be used to create a solver which is able to simulate correctly the evaporation of a droplet and of a liquid film.

Finally, we will try to couple these two solvers.

The following paragraph represents a brief overview of OpenFoam.

** OpenFoam Software**

OpenFoam (Open Source Field Operation And Manipulation) is a software written in C++ language. It's dedicated to resolve problems of Continuum mechanics and fluids mechanics. It was implemented on 1980 in Imperial college in London in order to improve a new simulation platform which will be stronger and more flexible than that used till now (Fortran).

So OpenFoam's use is more complex than others industrial software. In facts it's able to solve complex fluid flows using the "**Standards solvers**" it contains. Therefore, OpenFoam can solve CFD basic codes as well as compressible, incompressible or multiphase flows problems. OpenFoam solvers allow also solving problems of combustion, heat transfers and electromagnetism... More thann that, OpenFoam's user can easily establish a new solver by modifying an existing solver or by coding its own solver.

OpenFoam offers "**Standards utilities**" which are used to generate 3D meshes, to convert these meshes to OpenFoam files format in order to manipulate it using a lot of options. OpenFoam offers also a rich tools for post-processiong the velocities fields and the scalar fields...

Moreover OpenFoam has a large library "**Standard library**". It proposes multiples models that the user can choose as RAS and LES turbulence models ...

In this study, we will use some standard solvers,in particular "**SimpleFoam**" and "**IcoFoam**". We also create new solver "**MyIcoFoam**" that describes the evaporation problem.

To have more details about OpenFoam, here is the following link: http://www.openfoam.com/features/