Energy, exergy, and hydrodynamic performance of a spiral heat exchanger: Process intensification by a nanofluid containing different particle shapes

The energy, exergy, and hydrodynamic characteristics of employing a boehmite alumina nanofluid inside a spiral heat exchanger are investigated through CFD analysis regarding five different nanoparticle shapes. The numerical simulations are performed at four different volume fractions ranging from 0 to 0.04. It is found that utilizing the nanofluid at a higher volume fraction enhances the heat exchange amount, overall heat transfer coefficient (U), and effectiveness. It is unveiled that the highest rise in the U at the constant Reynolds number (Re) is about 25.4%, while this value at the constant pumping power ( W) is 6.35%. Additionally, concerning the thermal efficiency viewpoint, it is proposed to use the platelet-shaped nanoparticles at the constant Re. The oblate spheroid-shaped nanoparticles are suggested considering the energy efficiency perspective. Based on the second law of thermodynamics, the platelet-shaped particles demonstrate the best performance at the invariant Re, while at the constant (W) over dot, the oblate spheroid-shaped nanoparticles are recommended. The thermal irreversibility of the nanofluid in the case of constant Re only reduces using the oblate spheroid-shaped nanoparticles. The smallest exergy destruction in the case of constant (W) over dot belongs to the blade-shaped nanoparticles.

Automated summary

The study investigated the energy, exergy, and hydrodynamic characteristics of using boehmite alumina nanofluid in a spiral heat exchanger with five different nanoparticle shapes. It was found that higher volume fractions of nanofluid enhanced heat exchange amount, overall heat transfer coefficient (U), and effectiveness. Different nanoparticle shapes had varying effects on thermal efficiency and energy efficiency, with platelet-shaped nanoparticles performing best at constant Re and oblate spheroid-shaped nanoparticles being recommended for energy efficiency perspective.