UCLA

Supercritical CO2 (sCO2) Brayton cycles are promising power cycles due to their high the- oretical efficiencies and power densities. However, these cycles require the development of highly compact and effective sCO2 heat exchangers in order to achieve these potential ben- efits. This study experimentally characterizes the heat transfer performance of superalloy finned tubes in sCO2 cross-flow for eventual use in shell and tube heat exchangers. Two finned tube designs, with disc and parabolic fins, were tested against a bare tube in cross- flow with with Reynolds numbers ranging from 3,500 ≤ Re ≤ 8,000. Both finned tube designs significantly outperformed the bare tube, and fins were shown to increase the Nus- selt number of the tube by more than double in every case. The disc-finned tubes achieved higher overall heat transfer, but the parabolic fins are shown to have higher fin efficiency in every case. Lastly, this study compares the experimental results with correlations for Nusselt number and fin efficiency developed in previous studies.