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

In the present article a combination of a semi-empirical flow equation and a material equation is proposed that allows to calculate the pressure drop in beds composed of compressible, fibrous media. The model has been successfully implemented as an extension to the general-purpose CFD code ANSYS-CFX. Its capability to simulate the transient pressure drop build-up at non-uniformly loaded strainers in arbitrary three-dimensional geometries is demonstrated using a step-like flow geometry with a horizontally embedded strainer plate. It will be shown that the increasing pressure drop at the strainer has a rectifying effect on the flow field. The model could as well be implemented into system codes for nuclear reactor and containment simulation. Thus, existing system codes might be enabled for use in the risk assessment of loss-of-coolant accidents.