Numerical Study of Flow and Heat Transfer in a Curved Square Duct with Longitudinal Triangular Rib Using Al2O3/Water Nanofluid

Abstract

Flow and heat transfer characteristics in curved ducts are different from that of straight ducts. A numerical study of a steady and three dimensional laminar flow in a 180o curved square duct with longitudinal isosceles triangular rib has been conducted to investigate the effects of rib height, Dean number and volume fraction of Al2O3/water nanofluid on flow and heat transfer characteristics. ANSYS Fluent 17.0 commercial program is used for numerical simulation. Study is implemented for six Dean numbers changing from 250 to 1500, three different rib heights, and eight volume fractions varying from 0% to 5%. Velocity and temperature regions, heat transfer coefficient (h), pressure loss (investigated. Present results are compared with the literature results. It is seen that present results are in good agreement with the results of literature. Results show that Dean number (De), rib height (H) and volume fraction of nanofluid (vof) affect the heat transfer coefficient and pressure drop. It is seen that heat transfer coefficient may be increased by 59.0% for water as the working fluid when longitudinal isosceles triangular rib is used in curved square duct compared to ribless duct. Heat transfer coefficient may also be augmented by 30.8% using nanofluid as the working fluid in a curved square duct with rib. Results show that using longitudinal isosceles triangular rib in a curved square duct is advantageous.