Comparative study on the thermal-hydraulic performance of a shell and plate particle-SCO2 moving packed bed heat exchanger with various channel configurations

Abstract

This article proposes a predictive static model to evaluate the thermal-hydraulic performance of a shell and plate particle-SCO2 moving packed bed heat exchanger, with consideration of pressure drop, radiation and property variations. The results reveal that convection resistance on the SCO2 straight channel side occupies a large part of total thermal resistance in most design and off-design cases. A three-dimensional model inheriting conclusions from the static model is raised, which demonstrates that extremely short entrance region in the x-y plane hinders the overall heat transfer behavior of the SCO2 straight channel. Deservedly, suppressions of the development of thermal layers in the y direction will contribute to improving the thermal-hydraulic performance of the shell and plate particle-SCO2 moving packed bed heat exchanger. Four different fin configurations on SCO2 channel side are presented, analyzed and compared via the static model at the design-point case. Offset rectangular fins configuration behaves the best heat transfer enhancement in total heat transfer rate and overall heat transfer coefficient when compared with the original channel, followed by zigzag fins configuration, offset airfoil fins configuration and s-shaped fins configuration. Zigzag fins-modified channel expresses the worst hydraulic behavior, of which the pressure drop is nearly four times that of original straight channel. The pressure drop of channel with s-shaped fins nearly equals to that of the unmodified channel. Introduction of fins on SCO2 channel side reduces the ratio of convection resistance as a result of apparently increased SCO2 convection coefficients.