Study of thermal-hydraulic characteristics of a heat exchanger with perforated spiral fins

This study investigates the enhancement of thermo-hydraulic performance in compact heat exchangers, which are critical components in aerospace, automotive, and energy systems where size, weight, and thermal efficiency are paramount. While spiral fins and perforated surfaces individually improve heat transfer, their combined application in plate-fin heat exchangers remains largely unexplored. This work introduces a novel perforated spiral fin heat exchanger design, featuring bi-directional spiral fins with D-shaped perforations. This configuration aims to augment heat transfer efficiency by leveraging swirling flow within spiral channels and flow mixing induced by the perforations, while simultaneously mitigating hydraulic losses. Three-dimensional numerical simulations were performed to evaluate the impact of perforation height on performance, using the Colburn j-factor, Fanning friction f-factor, and performance evaluation criterion (JF) as metrics. Compared to a baseline spiral fin design, the proposed perforated spiral fin heat exchanger demonstrated significant improvements. At a Reynolds number of 3000, increasing the perforation height from 0 mm to 1.75 mm resulted in a j-factor enhancement from 8.55% to 14.77%, an f-factor reduction of up to 14.82%, and a JF factor increase ranging from 6.16% to 21.07%. These results confirm that the perforations effectively reduce pressure losses associated with flow separation and vortices while simultaneously increasing heat transfer efficiency. This research provides the first comprehensive analysis of the synergistic effects between spiral-induced swirl and fin perforation in a perforated spiral fin heat exchanger, offering new physical insights into their interaction.