Simulation on the hydraulic characteristics of SFR SG using “single-hole plate + tube bundles” (SHTB) hybrid porous media model

• A “single hole plate + tube bundles” (SHTB) hybrid porous media model was developed.
• A SHPPM model for simplifying the single hole plate was developed and validated.
• In window region, the tubes has little influence on the velocity distribution.
• A strategy for simplifying complex structures with CFD was proposed.

A “single-hole plate + tube bundles” (SHTB) hybrid porous media model was developed to investigate the hydraulic characteristics of sodium cooled fast reactor (SFR) steam generator (SG). In this hybrid model, single-hole plate porous media (SHPPM) model was used to discover subtle features induced by irregularly-broached tube support plates (TSP). While the tube bundles porous media was aimed at simplifying the heat transfer tube region, the combination of this two sub-models seized the balance between computational accuracy and calculating scale. In the SHPPM model, the commercial CFD software FLUENT was used to simulate the pressure drop of sodium when flowing through the single-hole plate under different inlet velocities. Two key factors-viscous resistance coefficient and the inertia resistance coefficient-were calculated by the V–ΔP formula. Comparing the results with the lateral flow velocity caused by the original sized single-hole plate model, this SHPPM model verified the validity and accuracy of the simulation. The hybrid porous media model reasonably simulated the maximum lateral flow velocity on the sodium side of SG, particularly in regions surrounding the TSPs. As a result, the maximal lateral flow velocity of the tube side entrance is 2.834 m/s and in the region around the TSPs is 1.3 m/s. Therefore, this work not only provided some useful flow field data to help forecast flow-induced vibration (FIV) phenomenon, but also proposed an innovative approach for simulating the SG of SFR.