ORIGINAL RESEARCH article
Front. Mech. Eng.
Sec. Heat Transfer Mechanisms and Applications
Volume 11 - 2025 | doi: 10.3389/fmech.2025.1698801
Investigations of thermal behavior, flow structure, and performance in a circular tube heat exchanger fitted with diamond-shaped orifice (DSO): A CFD assessment
Provisionally accepted
Amnart Boonloi1
Dr. Withada Jedsadaratanachai2*- 1King Mongkut's University of Technology North Bangkok, Bangkok, Thailand
- 2King Mongkut's Institute of Technology Ladkrabang, Bangkok, Thailand
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This study numerically investigates the enhancement of heat exchanger performance using a passive technique based on vortex generation. The proposed enhancement device, termed a diamond-shaped orifice (DSO), is a modified configuration that combines a conventional orifice plate with a conical ring. The DSO is inserted into a circular tube to modify the flow structure and induce strong vortices, thereby promoting convective heat transfer and improving the overall thermal performance. The effects of key geometric parameters, including the attack angle (α = 20°, 30°, and 45°), flow blockage ratio (FBR = 0.05–0.30), and pitch ratio (PRT = 1–2), are systematically examined under turbulent airflow conditions with Reynolds numbers ranging from 3000 to 20,000. The results reveal that incorporating the DSO generates intense swirling flow, which effectively disrupts the thermal boundary layer and enhances the convective heat transfer coefficient. The maximum Nusselt number improvement reached 7.16 times that of a plain tube, while the highest thermal enhancement factor (TEF) attained was 1.77, indicating a substantial improvement in heat exchanger performance without additional active energy input.
Keywords: Orifice, Thermal enhancement factor, numerical study, Vortex generator, heat exchanger
Received: 04 Sep 2025; Accepted: 15 Oct 2025.
Copyright: © 2025 Boonloi and Jedsadaratanachai. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.
* Correspondence: Dr. Withada Jedsadaratanachai, withada.je@kmitl.ac.th
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