Numerical Assessment of Nanofluids in Corrugated Minichannels: Flow Phenomenon and Advanced Thermo-hydrodynamic Analysis

Abstract

The current study addresses the influence of the amplitude of distinct corrugation patterns on heat transfer and the performance of nanofluids as a coolant. A novel combined approach has been presented here to optimize the heat transfer, incorporating both geometry modification and coolant optimization. The computational model evolved for single-phase, and turbulent flow conditions in three-dimensional corrugated minichannels (i.e. rectangular, sine-shaped, and V-shaped) with Reynolds number varying from 10,000 to 30,000. Considering a uniform heat flux of 10,000 W/m2, the investigation evaluates the thermal-hydraulic performance of single nanofluids (CuO/water, Al2O3/water, TiO2/water) and hybrid nanofluids (Al2O3CuO/water, Al2O3-TiO2/water), with volume fractions ranging from 1% to 3%. Various nanoparticle compositions exhibited a 25–30% increased heat transfer coefficient in the corrugated minichannel relative to the smooth one. An enhanced Nusselt number is evident due to the sophisticated corrugated arrangement dependent on the amplitude and patterns of the corrugations. The obtained energy ratio quantifies the effectiveness of a heat exchanger, whereas the Bejan number signifies the heat transfer being characterized by higher irreversibility, leading to a notable dissipation of energy. To account for the PEC (performance evaluation criterion) value above one, the corrugated geometries can outperform smooth channels. With an optimal thermal performance improvement of 22.19%, the 3% Al2O3CuO/water has been found to be the most effective nanofluid in the rectangular corrugated minichannel with the amplitude-to-wavelength ratio of 0.12.