Two-phase simulation of entropy generation and thermo-hydraulic behavior of a therminol/CuO-diamond nanofluid in a heat exchanger

Many researchers have optimized the thermo-hydraulic performance of heat exchangers (HE) used in industries. Using passive methods, such as nanofluid, turbulator, and fins can be beneficial in the field. In this paper, two-phase entropy generation and thermo-hydraulic behavior of hybrid nanofluid CuO-diamond/Therminol hybrid nanofluid in a HE equipped with high fins, micro fins, and turbulator are numerically examined. The volume fraction of nanoparticles changes from 0 to 4% and the flow Reynolds numbers (Re) are 14,000, 18,000, 22,000, and 26,000. Two-phase Eulerian-mixture method, k-ω turbulence model, finite volume method, and SIMPLEC algorithm are employed for the simulations. It is concluded that in terms of pressure drop, the use of tubes with micro fins is more favorable. The maximum values of the average Nusselt number (Nu) correspond to the heat exchanger equipped with high fins. The largest change in the average Nusselt number at all Reynolds numbers and volume fractions investigated is 32.67%, which occurs at a Reynolds number of 22,000 and a volume fraction of 4%. From the point of view of the total entropy generation in the presence of a hybrid nanofluid, it is more desirable to use a heat exchanger with micro fins.