PERFORMANCE TESTING OF THE 100 KW SHELL-AND-TUBE HEAT EXCHANGER USING LOW-FINNED TUBES WITH SUPERCRITICAL CARBON DIOXIDE ON THE SHELL SIDE AND WATER ON THE TUBE SIDE

摘要

BMPC completed thermal-hydraulic testing of a shell-and-tube heat exchanger with low-finned tubes for transferring heat from supercritical carbon dioxide (S-CO_2) on the shell side to water on the tube side. The measured performance of the shell-and-tube heat exchanger using low-finned tubes on the shell side showed that it achieved the specified thermal-hydraulic performance. The analytical approach to determine the performance of a shell-and-tube heat exchanger with low-finned tubes and S-CO_2 on the shell side compares well with the measured performance of the heat exchanger. The additional heat transfer area provided by the low-finned tubes remained fully effective - even with reduced flow velocity and the supercritical fluid near its critical point or a pseudo-critical temperature. Over a range of limiting flow conditions of the supercritical fluid, the thickness of the thermal boundary layer remained sufficiently thin to allow the low-finned tubes to remain fully effective. This result supports (but is not sufficient to prove) the general guidance to limit the estimated thickness of the thermal boundary layer to the fin height and twice the fin spacing to ensure the additional heat transfer area provided by the low-finned tubes remains effective.