A COMPREHENSIVE REVIEW ON PASSIVE HEAT TRANSFER AUGMENTATION TECHNIQUES FOR PIPE HEAT EXCHANGERS

Passive heat transfer augmentation techniques play a crucial role in enhancing the performance and efficiency of various thermal systems. This paper presents a comprehensive review of the state-of-the-art of passive heat transfer augmentation techniques, highlighting their principles, and thermo-hydraulic performance characteristics. The first part of the paper provides an overview of the fundamental principles underlying passive heat transfer augmentation. The discussion then delves into the concept of passive techniques, which rely on the intrinsic properties of the working fluids and the geometrical configurations to enhance heat transfer without the need for external energy input. The paper subsequently reviews a wide range of passive heat transfer augmentation techniques. It covers techniques such as surface modifications, including roughening, surface coatings, and porous media, which enhance convective heat transfer by altering the boundary layer characteristics. Furthermore, the paper explores the utilization of passive inserts, such as vortex generators, baffles, and turbulators, to induce fluid mixing and disrupt laminar flow, thereby increasing the convective heat transfer coefficient. Overall, this comprehensive review serves as a valuable resource for researchers, engineers, and practitioners interested in understanding and applying passive heat transfer augmentation techniques. It provides insights into the underlying principles and performance characteristics of these techniques, fostering further advancements in the field of thermal engineering. Received: April 29, 2023Revised: July 5, 2023Accepted: September 7, 2023