Validation of Models for Two-Phase Pressure Drop in Porous Media With Volumetric Heat Sources

An experimental investigation on flow-boiling in inductively heated porous media (particle bed of oxidized stainless steel spheres, 3 mm resp. 6 mm diameter) has been carried out. As coolant demineralized water was used. The main focus of the experiments is to determine the dryout heat flux and the pressure drop of the two-phase flow under various conditions. In the boiling experiments the inflow rate of the coolant was varied from 0 mm/s (self driven flow with water supply from the waterpool above the porous bed, “counter-current-flow”) to 7.2 mm/s (forced inflow condition at the bottom of the porous bed, “co-current-flow”). The experimental results are used to validate dryout models applied in reactor safety. The model verifications show clearly that models without the explicit consideration of the interfacial drag can only be utilized for co-current flows and are unsuitable for counter-current flows. Against it models with the explicit consideration of the interfacial drag show at least qualitative agreement for both, counter-and co-current flows.