Investigation of the effects of fin perforations on the thermal-hydraulic performance of Plate-Finned heat exchangers. (15th May 2022)

• Record Type: Journal Article
• Authors: Rauber, W.K.; Silva, U.F.; Vaz, M.; Alves, M.V.C.; Zdanski, P.S.B.
• Is Part Of: International journal of heat and mass transfer. Volume 187(2022)
• Publication Date: 2022-05-15
• Subjects: Heat exchanger devices -- Numerical simulation -- Wind tunnel experimental analysis -- Conjugate convection/diffusion problem -- Perforated finned surfaces; Heat -- Transmission -- Periodicals; Mass transfer -- Periodicals; Chaleur -- Transmission -- Périodiques; Transfert de masse -- Périodiques; Electronic journals; 621.4022
• DOI: 10.1016/j.ijheatmasstransfer.2022.122561
• Languages: English
• ISSNs: 0017-9310

Abstract

Highlights: The present work performs a hybrid numerical-experimental analysis to obtain the thermal and hydraulic performances of the perforated plate-finned heat exchangers. An experimental apparatus was devised for validation of the numerical data. The PEC parameter of the heat exchanger was enhanced with increasing the size of the fin perforations (either circular or diamond shape). The optimization metrics, heat transfers per unit mass and specific heat transfer of the fin surface, enhanced when the fins are perforated. Abstract: Design of fin profiles is a critical step in searching for more efficient heat exchangers. The present work performs a hybrid numerical-experimental analysis to obtain the thermal and hydraulic performances of the plate-finned heat exchangers. The analysis comprises a four-tube heat exchanger with in-line arrangement, being tested three fin patterns, i.e., rectangular with no insert (standard) and rectangular with diamond and circular perforations. The proposed methodology combines numerical simulation of the conjugate heat transfer problem (convection in the fluid/diffusion in the solid) with wind tunnel experimental data as boundary conditions. The ANSYS-Fluent® software is adopted to solve the three-dimensional average turbulent flow of air over the finned tubes within the framework of RANS model. The validation procedure compares the present results against empirical correlations for the Nusselt number available in the literature. Finally, a parametric study is addressed evaluating the influences of both the size and the shape of fin perforations upon the fluid dynamics and heat transfer behaviour. The main results indicate that larger sizes of the fin perforations (either circular or diamond shape) will enhance the comprehensive Performance Evaluation Criterion – the PEC parameter – and mass/volume thermal efficiency of the heat exchanger.