Hydrodynamic Transient Assessment of a Draining Tank

Abstract

In this paper we present a simplified model using OpenFOAM® suite to study the hydrodynamic behavior of a draining tank, which is part of a second shut down system of an experimental nuclear reactor. This problem involves the presence of a free surface between a liquid and a cover gas which should be accurately described during the draining transient of the liquid inside the tank. By using a three grid approach for the relevant parameter to compute the height of drained liquid, we bound the uncertainty in the calculations induced by the spatial discretization in agreement with the achievable computing times. We compute the level of the surface in a local manner and by using global balances.
We compare the solution for the discharge dynamics obtained by the two different methods showing consistency and concordance between them. We also present an analytical approach which points out the lowest threshold for the discharge time.