A Comprehensive Compendium on Passive Augmentation Techniques for Enhancement of Single-Phase Heat Transfer Coefficients in Heat Exchanger Tubes under Laminar and Turbulent Flow Conditions

Abstract

Several passive techniques can substantially improve the heat transfer performance of conventional heat exchangers. Passive methods persistently use heat transfer augmentation inside tubular sections, which tackle dominant thermal resistance. The thermal resistance in turbulent flow is primarily due to a thin viscous sublayer near the tube wall. This proliferates into the cross-section of the conduit in the case of laminar flows due to the existence of a relatively thicker boundary layer. This urges disturbance in the entire fluid throughout the cross-section in laminar flows, whereas augmentation devices are usually located close to the wall for turbulent flows. Most of these methods yield increased fluid residence time within the system by inducing swirling motion. The form of disturbance in the flow field is the characteristic of the passive technique used to prolong the fluid residence time and is exhibited differently in both flow regimes. The present article showcases a comprehensive review of heat transfer enhancement through thermo hydraulic performance assessment of these methods reported in the literature. The comparison is based on ratios of Nusselt numbers, first at the same Reynolds numbers, and then, at equal pumping power with constant heat transfer area.

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No potential conflict of interest was reported by the authors.

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Notes on contributors

Prashant Wasudeo Deshmukh

Prashant Wasudeo Deshmukh is currently associated with the College of Engineering, Pune, India, as a faculty in the Mechanical Engineering Department. He acquired his Ph.D. from Indian Institute of Technology Bombay, India. He has been involved in academics for the past 16 years. He has been associated with several reputed engineering educational institutes and offered his services to process industries. He has undertaken several projects in passive heat transfer augmentation techniques for single-phase heat transfer.

Satyajit Vilas Kasar

Satyajit Vilas Kasar earned his Ph.D. in thermal-hydraulics for nuclear reactor safety from Indian Institute of Technology Bombay. His research area is mainly experimental heat transfer in single-phase and two-phase flows. He has undertaken projects to characterize critical heat flux in rod bundle and stability boundaries in multichannel natural circulation systems. He has been active in academics for the past 13 years. Currently, he is working as an assistant professor in Mechanical Engineering at Sandip Foundation, Nashik (India).

Siddini Venkatesh Prabhu

Siddini Venkatesh Prabhu is a Professor at the Department of Mechanical Engineering, Indian Institute of Technology, Bombay, India. He obtained his Ph.D. from Indian Institute of Technology Bombay, India. His research interests are flow metering, heat transfer studies involving jet impingement, fire dynamics, renewable energy (hydrokinetic turbines and wind turbines), heat transfer enhancement, gas turbine blade cooling, melting, and solidification of phase change material and metals and thermal hydraulics of porous media.