Enhancing thermal efficiency in helical heat exchangers: A CFD study on twisted tube configurations

Heat exchangers are crucial components for enhancing energy efficiency in various industrial applications. This study investigates the efficiency of a helical heat exchanger incorporating twisted tubes with different pitch lengths, focusing on their impact on thermal performance compared to traditional circular tubes. Computational Fluid Dynamics (CFD) simulations were used to examine the Nusselt number, resistance factor, and Performance Evaluation Criteria (PEC) at Reynolds numbers of 1000, 1500, 2000, and 2500. Results indicate that twisted tubes enhance heat transfer efficiency, particularly at higher Reynolds numbers. At a Reynolds number of 2500, PEC index increases of approximately 20%, 22%, and 14% were observed for pitch lengths of 17 mm, 27 mm, and 37 mm, respectively. However, at lower Reynolds numbers, the benefits diminish, with PEC increases generally below 15%. The findings highlight the importance of optimizing pitch length to balance heat transfer enhancement with pressure drop, suggesting that a pitch length of 27 mm offers the most favorable performance. This study provides design guidelines for twisted tube heat exchangers to enhance thermal management in industrial applications.