Airside thermal performance of louvered fin flat-tube heat exchangers with different redirection louvers

Saleem, Arslan ORCID: https://orcid.org/0000-0001-7780-0258 and Kim, Man-Hoe 2022. Airside thermal performance of louvered fin flat-tube heat exchangers with different redirection louvers. Energies 15 (16) , e5904. 10.3390/en15165904

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Abstract

The performance of heat exchangers is severely limited by airside thermal resistance. The effect of redirection louvers (RLs) on the airside thermal performance of a compact flat-tube louvered fin heat exchanger was investigated. A steady-state 3D numerical analysis was conducted for different fin configurations by varying the number of RLs (NRL = 1, 2, 3, and 5). Conjugate heat transfer analysis was performed at the low Re (50−450) for domestic and transport air-conditioning applications. Geometric parameters such as louver pitch, louver angle, fin pitch, and flow depth were set as 1.7 mm, 27°, 1.2 mm, and 20 mm, respectively. The effective heat transfer fin surface areas of different fin configurations were also kept identical for a comparative analysis. The influence of the RLs on the airside thermal−hydraulic performance was analysed by exploring the local and average Nusselt numbers, pressure drop, Colburn j factor, friction factor f, performance evaluation criteria (PEC), and flow efficiency of different fin configurations. The numerical results revealed that the asymmetric fin configuration with two RLs (NRL = 2) showed the best heat transfer performance for the entire Re range. It resulted in a 33% higher average Nusselt number, causing a 24% higher pressure drop compared to NRL=5. At low flow velocities (Re 75), NRL = 3 showed better PEC; however, at high flow velocities (Re > 75), NRL = 1 outperformed other fin configurations. Finally, it was noted that increasing the number of RLs reduced the amplitude of the wavy-shaped flow formed between the neighbouring louvered fin, consequently deteriorating the flow efficiency.

Item Type:	Article
Date Type:	Published Online
Status:	Published
Schools:	Engineering
Additional Information:	License information from Publisher: LICENSE 1: URL: https://creativecommons.org/licenses/by/4.0/
Publisher:	MDPI
Date of First Compliant Deposit:	17 August 2022
Date of Acceptance:	12 August 2022
Last Modified:	10 May 2023 20:11
URI:	https://orca.cardiff.ac.uk/id/eprint/152008

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