Time-dependent analysis of heat transfer enhancement and entropy generation of hybrid nanofluids in a tube with a solid and elliptical cut twisted tape insert with non-uniform heat flux

Khfagi, A. M. I., Hunt, G. , Paul, M. C. and Karimi, N. (2023) Time-dependent analysis of heat transfer enhancement and entropy generation of hybrid nanofluids in a tube with a solid and elliptical cut twisted tape insert with non-uniform heat flux. Energy Sources Part A: Recovery, Utilization, and Environmental Effects, 45(4), pp. 11315-11340. (doi: 10.1080/15567036.2023.2256691)

Abstract

This numerical study investigates the improvement of transient heat transfer in a plain tube using hybrid nanofluids consisting of solid particles and twisted tapes with elliptical cuts, under non-uniform heat flux conditions. The analysis includes the calculation of the Bejan number and entropy production. Different working fluids, including water, CuO/water nanofluid, and a hybrid nanofluid with a 2% volume concentration of Al2O3-Cu/water, are used with varying concentrations of the hybrid nanofluid ranging from 1% to 4%. Effects of heat flux distribution and local concentration ratio (LCR) are investigated. The computational results indicate that conventional and elliptical cut twisted tapes enhance transient heat transmission. A slight rise in the heat transfer coefficient is observed when the fluid has higher thermal conductivity. The flow velocity gradually stabilizes over time. The hybrid nanofluid of (Al2O3-Cu/water) significantly affects transient heat transmission, reducing the maximum temperature difference by approximately 4.1% compared to water and 6.2% compared to the nanofluid. Transient heat transmission is further intensified by TECT. Moreover, frictional entropy production dominates the system’s irreversibility. This study contributes to the understanding of transient heat transfer enhancement and its dependence on hybrid nanofluids, providing insights for engineering applications.

• Item Type: Articles
• Additional Information: This work was supported by the Ministry of Higher Education and Scientific Research in Libya.
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Paul, Professor Manosh and Hunt, Dr Graeme and Karimi, Dr Nader and KHFAGI, Amir Mohamed Ibrahim
• Authors: Khfagi, A. M. I., Hunt, G., Paul, M. C., and Karimi, N.
• College/School: College of Science and Engineering > School of Engineering; College of Science and Engineering > School of Engineering > Systems Power and Energy
• Journal Name: Energy Sources Part A: Recovery, Utilization, and Environmental Effects
• Publisher: Taylor and Francis
• ISSN: 1556-7036
• ISSN (Online): 1556-7230
• Published Online: 18 September 2023
• Copyright Holders: Copyright © 2023 The Author(s)
• First Published: First published in Energy Sources Part A: Recovery, Utilization, and Environmental Effects 45(4):11315-11340
• Publisher Policy: Reproduced under a Creative Commons license