Mixed Convection Heat Transfer Inside a Lid-driven Trapezoidal Cavity For H_2 O-Cu-〖Al〗_2 O_3 Hybrid Nanofluid

Abstract

The mixed convection inside a trapezoidal lid-driven cavity for a circular cylinder heat source was numerically investigated via Ansys commercial program (ANSYS Fluent 2021 R2 and 2022 R1). This study employed two distinct fluids, namely H_2 O and Water-Cu-Al_2 O_3 hybrid nanofluid. The upper wall maintains a steady velocity while the lower wall stays motionless. Both walls remain cold. However, the inclined cavity walls are insulated via adiabatic insulation. The present investigation has undergone validation and comparison with previously published research, yielding a significant degree of correspondence with an average relative difference of around 1.62%. The outcomes comprise of three distinct Richardson number values: 0.01, 1, and 10, radius ratios of 0.20 and 0.25, four inner cylinder positions (center, right, top, bottom), and four inclination angles: 0°, 45°, 90°, and 180°. It is demonstrated that bottom position of (0, −0.12) is the desirable position with the largest mean Nusselt number across the angles (???? = 0°, 45°, and 90°). When the position lies at the top (0, 0.12), and the angle is 180°, the maximum heat transfer rate is achieved.