Pure mixed convection in a Non-Newtonian fluid filled lid-driven chamber with discrete bottom heating

Abstract

This study has examined pure mixed convective power-law fluid flow in a lid-driven square chamber with a discrete thermal source at the bottom surface. The finite element technique solves the governing Navier-Stokes and heat energy equations. A parametric simulation is executed by changing the moving walls' direction into three cases along with the simultaneous change of Grashof and Reynolds numbers, power-law index within 0.6 ≤ n ≤ 1.4 and non-dimensional thermal source length within 0.25 ≤ ε ≤ 1.00. The results have been represented in terms of isotherm and streamline plots, evaluation of the mean Nusselt number of the thermal source, the bulk and the maximum fluid temperatures. This research indicates that the smaller the heat source, the higher the heat transfer, and that the heat transfer performance of the smallest heat source can be as high as 76% greater than that of the largest heat source. When both sidewalls move oppositely, heat transmission efficiency is 132% and 52% greater than in the first (both walls move downward) and second (both walls move upward) cases, respectively. Furthermore, the heat transfer performance changes around 26.32%, −3.45%, and −18.18%, with the rising value of the power-law index for the three cases, respectively.

Keywords

• Non-Newtonian
• Square chamber
• Discrete heat source
• Power-law fluid
• Moving wall
• Mixed convection