Résumé:
The work presented in this thesis is related to the studies of laminar natural convection in a horizontal cylindrical tank of storage of the cryogenic fluids. This study is relative to a twodimensional simulation of a convective flow in transitory mode in geometry similar to that of the tank for the prediction of the behaviors thermics and dynamics of the fluid inside the tank. The numerical simulations are structured, according to the position and the nature of the heat flow, into two parts. The first represents the case of a heat flow constant and fixed which receives firstly on the lower wall of the tank (tank heated by bottom), then, on the side wall (laterally heated tank), and on the higher wall (tank heated by the top) respectively. The second part constitutes the case of a heat flow constant and mobile; this flow is comparable with the solar flow which receives at the beginning on part of surface external of the tank, then, it will move along the day according to the position of the sun. The velocities and temperatures fields in the system were given through solving the equations of the dynamics of the fluids by using the commercial code Fluent which uses the finite volume method.
