INTERNATIONAL JOURNAL OF EXERGY, cilt.46, sa.3-4, ss.324-339, 2025 (SCI-Expanded)
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 (phi = 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.