Comparative analysis of heat transfer enhancement in vortex generators using nanofluids under turbulent flow conditions

To address industrial challenges in thermal efficiency equipment, current research emphasizes optimizing system designs and employing efficient heat transfer fluids. In this paper, the turbulent heat transfer performance of nanofluids in a TG-type vortex generator is investigated by numerical simulations using the mixture model at Re = 2,600-17,000 operating conditions. Gap-Diameter ratio (G/D) are investigated in order to select a vortex generator structure with the optimal performance (Best performance when G/D = 1.2). Then the impact of nanofluid type, concentration, and CNT diameter on heat transfer was quantified. It was found that the Nusselt number of Vortex generators was by 1.75-2.44 times higher than that of the empty tube. The nanofluids Al2O3-H2O, SiC-H2O and CNT-H2O achieved Nu(avg) increases of 1.04-1.17, 1.30-1.46 and 5.36-5.98 times over water, respectively. By increasing the Fc and suppressing the S-T, CNT can reduce total irreversible losses while achieving efficient heat transfer. In addition, the comprehensive heat transfer performance of single-walled carbon nanotubes (SWCNT) is better than that of multi-walled carbon nanotubes (MWCNT). MWCNT = 50 nm, MWCNT < 10 nm and SWCNT exhibited PEC enhancements of 4.03-5.07, 4.48-5.70, and 6.92-9.07 times over water, respectively. This study provides valuable insight into the optimization of heat exchangers and other industrial thermal systems.