Mitigation of fouling with swirling flow induced in 3-D double-sided straight channel for printed circuit heat exchanger

Abstract

Fouling should be considered in the design of a printed circuit heat exchanger (PCHE) for industrial applications. The swirling flow, which is known to mitigate fouling in heat exchangers, can incorporate this aspect; however, realizing these flow characteristics in compact heat exchangers such as PCHE is difficult. Thus, this study proposed a three-dimensional (3-D) designed PCHE channel. To induce swirling flow, it was designed to face two semicircular straight channels with angles such that the interaction between the mainstreams in different flow directions induced a swirling flow. Compared to conventional two-dimensional (2-D) PCHE channels (straight, zigzag, and airfoil channels), the swirling flow induced in the proposed 3-D PCHE channel uniformly increased the wall shear stress while minimizing flow separation or recirculation. This minimized the low wall shear stress that was more likely to be fouled. A comparative evaluation of the thermal-hydraulic performance of the investigated channels was conducted by comparing the volume goodness factors under the equal hydraulic diameter. The proposed 3-D channels exhibited the potential to mitigate fouling, as well as a thermal-hydraulic performance comparable to that of conventional 2-D PCHE channels. Therefore, the proposed 3-D channel can be suggested as an advanced PCHE design option for high thermal-hydraulic performance and mitigation of fouling. Furthermore, because the swirling flow is known to mitigate fouling in heat exchangers as well as the heat transfer deterioration of sCO2, a double-sided straight channel with swirling flow is expected to be competitive.