Mitigation of local-blockage-induced flow maldistribution in supercritical CO2 printed circuit heat exchangers through lateral interconnections

Local blockage disturbs the hydraulic-resistance balance of parallel microchannels in printed circuit heat exchangers (PCHEs), but its system-level influence on supercritical CO 2 flow redistribution remains insufficiently understood. In this study, conjugate heat-transfer simulations were performed for a representative periodic PCHE unit with seven parallel rectangular channels on each side. Local blockage was treated as a position-dependent resistance perturbation in a coupled microchannel network. The effects of blockage ratio, blocked-channel number, blockage side, and lateral interconnections on flow maldistribution and thermo-hydraulic performance were examined. Results show that local blockage produces network-scale redistribution through upstream static-pressure accumulation, throat acceleration, downstream momentum deficit, and increased flow through open channels. For 91% blockage in one hot-side channel, the blocked-channel mean Nusselt number ( Nu ) decreases to about 45% of the clean value, whereas the open-channel mean Nu increases by 10.5% owing to flow redistribution toward the open channels. Pressure drop and the performance evaluation criterion are more sensitive to blockage than the total heat-transfer rate, indicating that hydraulic penalty dominates early performance deterioration. Hot-side blockage causes stronger pressure-drop amplification than cold-side blockage because of the lower density and higher velocity of supercritical CO 2 on the hot side. Lateral interconnections convert blockage-induced transverse pressure differences into passive compensating flow, reactivating blocked-channel downstream regions and reducing exit maldistribution. Under dual-side multi-channel blockage, lateral interconnections reduce the hot-side pressure drop by up to 32.7% and increase hot-side PEC by 20.1–54.1% relative to no-interconnection cases. These results establish lateral interconnections as a passive strategy for blockage-tolerant PCHEs.