Optimization and Comprehensive Investigation of the Effect of Geometrical Parameters on Entransy, Exergy & Entropy in Finned Tube Heat Exchangers

Document Type : Research Article

Authors

Faculty of engineering, Shohadaye Hoveizeh Campus of Technology, Shahid Chamran University of Ahvaz, DashteAzadegan, Iran.

Abstract

In this study, the impact of geometric characteristics on the entransy dissipations total number (EDTN), the exergy loss number (ELN), and the entropic potential losses number (EPLN) in finned tube heat exchangers (FTHEs) is investigated. Also, by using the NSGA2 method, the EDTN as the main part of irreversibility in the studied heat exchanger is minimized. The EDTN consists of two terms: thermal and frictional. In this research, the expressions of thermal and frictional entransy dissipations are minimized as two independent objective functions .The transverse tube pitch, mass flow rate, hot fluid inlet temperature, cold fluid outlet temperature, tube's outer diameter, shape width, and shape height were chosen as optimization variables. The research revealed that as the tube's outer diameter increases, the EDTN and the EPLN decrease and the ELN increases. It has been discovered that the values of the EDTN, EPLN, and ELN were 0.72, 0.4, and 0.48, respectively. It is obvious that the EDTN compared to the EPLN and the ELN is the main factor in the irreversibility investigation. It was also observed that by minimizing the EDTN, the efficiency of the FTHE enhances by about 45.5% and the heat transfer rate is approximately 6.15 times its value prior to optimization. In addition, the optimization results indicated that the EPLN and the ELN were reduced by 66% and 34%, respectively, compared to the initial results.

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