Transient Mixed Convection in a Two-Sided Lid-Driven Differentially Heated Square Cavity Utilizing Nanofluids

Abstract

Transient behaviour of mixed convection inside a two-sided lid-driven differentially heated square cavity filled with nanofluids is investigated numerically to gain insight into convective recirculation and flow processes evolved with time. A model is developed to analyse the behaviour of nanofluids taking into account the solid volume fraction (π). The transport equations are solved numerically using the finite volume approach and a SIMPLE algorithm on a non-staggered grid with deferred QUICK scheme. Comparisons with previously published work are performed and found to be in excellent agreement. The solution procedure is moved with small values of τ so that a transient behaviour can be captured. Richardson number, Ri = Gr/ Re2, a measure of relative importance of natural and forced convection modes on the heat transfer, is taken as 1 so that the phenomena of mixed convection can be understood effectively. Copper—water nanofluid is used with Pr = 6.2 and solid volume fraction π is varied as 0.0, 0.08, and 0.16. Detailed results are presented for streamline and isotherm patterns. A comparison of average Nusselt number shows that heat transfer is more in the case of π = 0.16. The present study focuses on the transient analysis of several parameters on the heat transfer characteristics of nanofluids within the enclosure.