Optimal design of geometrical parameters and flow characteristics for Al2O3/water nanofluid inside corrugated heat exchangers by using entropy generation minimization and genetic algorithm methods

摘要

In this study, the effort has been focused on optimal amounts of the geometric and hydrodynamic characteristics of turbulent Al2O3/water nanofluid flow within the corrugated heat exchangers (HEXs). The optimization is carried out using entropy generation minimization (EGM) approach and genetic algorithm (GA). All of the geometric and hydrodynamic parameters, including corrugation depth (a), corrugation pitch (w), length of the corrugation section (L), height of the corrugation section (H), phase shift angle (theta), nanoparticles volume fraction (phi) and Reynolds number (Re), are taken into account in the optimization process. The results reveal that the addition of Al2O3 nanoparticles to the base fluid significantly enhances heat transfer and also a slight increment in system irreversibility. Adding 4% Al2O3, with the constancy of the other parameters, causes 5% increment in irreversibility at most. Applying the optimization based on the all of the parameters together results 5.41 mm, 148.84 mm, 1.06 mm, 13.80 mm, 4.35 degrees, 14,757 and 3.19% for optimum values of H, L, a, w, theta, Re and phi, respectively.