Optimization of louvered-fin heat exchanger with variable louver angles

• Published in: Applied thermal engineering Vol. 91; pp. 138 - 150
• Main Authors: Jang, Jiin-Yuh, Chen, Chun-Chung
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 05.12.2015
• Subjects: Computer simulation; Conjugate gradient method; Heat exchangers; Infrared; Louvered-fin heat exchanger; Louvers; Mathematical analysis; Mathematical models; Optimization; Reduction; Variable louver angle; Conjugate gradient method; Variable louver angle; Louvered-fin heat exchanger; Optimization
• ISSN: 1359-4311
• DOI: 10.1016/j.applthermaleng.2015.08.009

The optimization of the variable louver angle (Δθ) and initial louver angle (θi) for a louvered-fin heat exchanger was determined numerically using the conjugate gradient method. The area reduction ratio relative to a plain surface was the objective function to be maximized. A search for the optimal variable louver angle (Δθ) and initial louver angle (θi), in the ranges of +0° < Δθ < +4° and 18° < θi < 30°, respectively, was performed. The results show that the maximum area reduction ratios are 48.5%–55.2% for the optimal design of (Δθ, θi) at ReH = 133–1199 (Uin = 1.0–9.0 m/s). In order to validate the reliability of the numerical simulation procedure, a comparison of experimental and numerical simulation results was made with the scaled-up testing. This article shows the temperature for the scaled-up louvered fin as determined from infrared thermovision and numerical simulation, respectively. A comparison of images shows that both methods give similar temperature distributions across the entire louvered fin. In addition, it shows comparisons of j and f between the simulation and experimental results. The results show good agreements, with a maximum discrepancy of 12%. •Optimization of variable and initial louver angle was performed.•The maximum area reduction ratios may up to 44–51%.•Numerical results were validated by Infrared thermovision data.