Natural convection in a rectangular tall cavity in the presence of an oscillating and rotating cylinder

Abstract

In this paper, the natural convection in a rectangular tall cavity with a rotating and oscillating cylinder is investigated. The amount of heat transfer due to natural convection for the cavity without a cylinder has been compared with previous references, which is in good agreement with previous results. The effect of changing the width of the cavity (1-7 L), cylinder radius (0.05-0.25 L), angular velocity (-7.5 to 7.5 rad/s), coordinates of the cylinder in the horizontal direction of the hot wall (0.15D-0.85D) and the coordinates of the center of the cylinder in the vertical direction (-0.3D to 0.5D) on the heat transfer has been studied. Cylinder oscillations in the y- direction is assumed sinusoidal. The obtained results revealed that the radius of the cylinder and the distance of the cylinder from the hot wall are two factors affecting the heat transfer and the optimal state was found for them in which the heat transfer is maximum. Also, the rotation and vertical movement of the cylinder has improved heat transfer compared to the static cylinder. With increasing rotational speed, amplitude and frequency of oscillations, the amount of heat transfer increases. In the case where the rotation of the cylinder is clockwise, the Heat transfer is more significant than in the case of counterclockwise rotation. Using a porous cylinder on the heat transfer rate has been investigated. The use of porous cylinders in this case improves heat transfer and by increasing the porosity coefficient in the porous media, the amount of heat transfer is enhanced by about 13%.