Optimization study on PCHE channels for lead-bismuth eutectic and supercritical carbon dioxide coupled flow and heat transfer

The intermediate heat exchanger (IHX) is a key component in lead-cooled fast reactors (LFRs) between the lead-bismuth eutectic (LBE) loop and supercritical carbon dioxide (sCO2) Brayton cycle. In this paper, the LBEsCO2 flow and heat transfer in printed circuit heat exchanger channels is studied. Firstly, for a typical identical semicircular channel on the hot and cold side, the best hot and cold flow rate ratio in the constraint of design temperature and pressure drop requirements was explored. On this basis, the flow and heat transfer characteristics of different channel patterns were comparatively analyzed. The "rectangle-to-two" channel pattern has the largest heat transfer in per unit volume, which is 176 % greater than the typical identical semicircular channels. Finally, the correlation equations of Nusselt number and Fanning friction factor were established. It provides a basis for the flow and heat transfer calculations and structural optimization design of the LFRs.