Promising Effects of Various Types of Twisted Tapes on the Printed Circuit Heat Exchangers Filled with Supercritical Carbon Dioxide: A Numerical Study

Abstract

Printed circuit heat exchangers (PCHEs) are compact and efficient devices widely used for heat transfer in various applications. The heat transfer performance of PCHEs can be further improved through the use of twisted tape inserts, which enhance fluid mixing and induce secondary flows. The effect of twisted tape inserts on the flow and heat transfer characteristics of PCHEs with straight channels is investigated using numerical analysis. Different twisted tape configurations are examined, including variations in twist ratio, pitch, and orientation. Additionally, a novel design involving rotating plates inside the straight channels is proposed, which can be fabricated using 3D printing or similar techniques. The performance of these rotating plates is compared with that of conventional twisted tapes and plain PCHEs. Results indicate that twisted tapes and rotating plates significantly enhance heat transfer, with the plus-shaped twisted tape increasing the local heat transfer coefficient by up to 37.56 % and the average Nusselt number to 64.27. This enhancement is accompanied by an increase in pressure drop and pumping power, up to 48.63 %. The double horizontal twisted tape, with a PEC number of 1.46832, is identified as the optimal design. These findings underscore the potential of these methods for improving heat transfer in PCHEs. © 2024