Assessment of straight, zigzag, S-shape, and airfoil PCHEs for intermediate heat exchangers of HTGRs and SFRs

A promising candidate for the intermediate heat exchanger (IHX) in high temperature gas-cooled reactors (HTGRs) and sodium-cooled fast reactors (SFRs) is a printed circuit heat exchanger (PCHE) due to its high effectiveness and compactness. We developed the thermal-hydraulic correlations for an airfoil PCHE by three-dimensional computational fluid dynamics (3D-CFD) analysis, which are applicable over the range of Reynolds number from 0 to 150,000, including helium in laminar region and CO2 in turbulent region. Proposed Fanning factor correlation for the entire range showed the normalized root mean square deviation (NRMSD) as 2.52%. NRMSDs for two Nusselt number models for each flow region were calculated as 4.66% and 0.82%. We compared the total cost considering material and operation cost for the IHXs in HTGRs and SFRs with 4 types of PCHEs, which are straight, zigzag, S-shape, and airfoil PCHEs. For the IHXs of pebble bed modular reactor (PBMR) operating in the laminar region, the zigzag PCHE is the best option because of its lowest pressure drop and relatively high heat transfer area. The straight PCHE for the IHXs of Kalimer-600 is definitely the best option due to its much lower pressure drop, which is one reactor type of the SFRs operating in the turbulent region. (C) 2014 Elsevier B.V. All rights reserved.