Implementation of a pressure drop model for the CFD simulation of clogged containment sump strainers

The present study aims at modelling the pressure drop of flows across growing cakes of compressible, fibrous materials which may form on the upstream side of containment sump strainers after a loss-of-coolant accident (LOCA). The model developed is based on the coupled solution of a differential equation for the change of the pressure drop in terms of superficial liquid velocity and local porosity of the fibre cake and a material equation that accounts for the compaction pressure dependent cake porosity. Details of its implementation into a general-purpose three-dimensional computational fluid dynamics code (CFD) are given. An extension to this basic model is presented, which simulates the time dependent clogging of the fibre cake due to capturing of suspended particles as they pass trough the cake. The extended model relies on empirical relations which model the change of pressure drop and removal efficiency in terms of particle deposit in the fibre cake.