Effects of the rectangular groove dimensions on the thermal features of the turbulent Al2O3-water nanofluid flow in the grooved tubes

 The forced convection heat transfer of turbulent Al2O3-water nanofluid flow inside the grooved tubeswith the different aspect ratio of the rectangular grooves is numerically investigated. The governingequations have been solved using finite volume method (FVM) coupled with SIMPLE algorithm. It isassumed the heat flux is constant on the grooved walls. The Single-phase approach is applied for thecomputation of the nanofluid flow. The Nanoparticles volume fraction is in the range of 0-5% and flowReynolds number is in the range of 10,000-35,000. Comparisons between the numerical results andavailable experimental data show that among different turbulence models, k-ε model with enhanced walltreatment gives the better results. The results show that the heat transfer coefficient increases withnanoparticles volume fraction and Reynolds number but it is accompanied by pressure dropaugmentation. From the results, it is concluded that the grooved tubes with Al2O3-water nanofluid floware thermodynamically advantageous. The Correlations for heat transfer coefficients have been presentedfor grooved tubes in different aspect ratios using the numerical results. The optimum geometric ratios inwhich the entropy generation is minimized are also determined.