Work

Heat Transfer Enhancement of Tube Bundle with Symmetrically Inclined Annular Fins for Waste Heat Recovery

Year: 2025

Type: article

Abstract: Enhancing convective heat transfer efficiency in waste heat recovery applications is critical for improved energy utilization. This study conducts a convective heat transfer optimization of a tube bundle for waste heat recovery of flue gas based on an exergy destruction minimization method. The results indicate that the multi-longitudinal vortex flow is the optimal flow field for heat transfer in a tube bundle. To achieve this flow field, a novel tube bundle equipped with symmetrically inclined annular fins has been proposed and the thermal–hydraulic performance has been numerically investigated. The effects of key geometric parameters, including fin inclination angle (θ = 30°, 35°, 40°, 45°, 50°) and fin diameters (D = 62, 68, 74 mm), were systematically analyzed under varying inlet velocities (8–16 m/s) and heat flux densities (23,000–49,000 W/m2) at inlet temperatures of 527 K and 557 K. Results demonstrate that both the convective heat transfer coefficient (h) and tube bundle power consumption (Pw) increase with rising fin diameters and inclination angle. At a constant D, h and Pw exhibit a positive correlation with θ. Crucially, compared to a traditional smooth-tube bundle, the optimal annular fin configuration (θ = 45°, D = 74 mm) achieved a significant enhancement in the convective heat transfer coefficient of 22.76% to 31.22%. This improvement is attributed to intensified vortex generation near the fins, particularly above and below them at higher angles, despite a reduction in vortex count. These findings provide valuable insights for the design of high-efficiency finned tube heat exchangers for flue gas waste heat recovery.

Source: Energies

DOI: 10.3390/en18184964

Authors: Jiahui Wang, Hanxiao Liu, Liming Wu, Liyuan Yu, Peng Liu, Zhichun Liu

Institutions: Wuhan Institute of Technology, Huazhong University of Science and Technology

Language: English

Topic: Heat Transfer and Optimization

Subfield: Mechanical Engineering

Field: Engineering

Domain: Physical Sciences

SDG: Affordable and clean energy

Open Access status: gold

Estimated APC paid: $3,137