Title: Entropy generation in a U-tube flow system containing MWCNT-Fe₃O₄/water hybrid nanofluid with uniform and non-uniform magnetic fields

Authors: Emrehan Gürsoy; Engin Gedik

Addresses: Audit Department, Kardemir Karabük Iron Steel Industry Trade & Co. Inc., Karabük, Türkiye; Center of Energy Applications Laboratory, Karabük University, Karabük, Türkiye ' Center of Energy Applications Laboratory, Karabük University, Karabük, Türkiye; Department of Mechanical Engineering, Karabük University, Karabük, Türkiye

Abstract: The study analyses entropy generation in a U-tube used in shell and tube heat exchangers, using both passive and active techniques. MWCNT-Fe₃O₄/water hybrid nanofluid (φ = 0.001% and 0.003%) under laminar flow conditions (117.1 ≤ Dn ≤ 234.2) and magnetic fields were evaluated. Results showed that tube position did not impact irreversibility. However, MWCNT-Fe₃O₄/water hybrid nanofluid enhanced system efficiency, reducing total entropy generation at the rate of 13.0% and 18.0% for = 0.001% and 0.003%, respectively, at Dn = 234.2. Conversely, increasing the magnetic field raised total entropy generation, negatively impacting irreversibility.

Keywords: entropy generation; MHD; U-tube; uniform and non-uniform magnetic field; MWCNT-Fe₃O₄/water hybrid nanofluid; laminar flow regime.

DOI: 10.1504/IJEX.2025.146047

International Journal of Exergy, 2025 Vol.46 No.3/4, pp.324 - 339

Received: 27 Apr 2024
Accepted: 22 Dec 2024
Published online: 02 May 2025 *

Full-text access for editors Full-text access for subscribers Purchase this article Comment on this article