Numerical solution of non-newtonian nanofluid using buongiorno’s mathematical model

Abstract

In this thesis, the effect of non-Newtonian nanofluid on mixed convection heat and mass transfer in a square enclosure utilizing Buongiorno's model have been investigated. More specifically, here adopting Buongiorno's mathematical model for nanofluid, where Brownian motion and thermophoresis parameter shows significant effects on nanofluid flow and heat transfer which can affect nanoparticle concentration variations. The physical problems are represented mathematically by different sets of governing equations along with the corresponding boundary conditions. Using the appropriate transformation, the governing equations containing the equations of continuity, momentum, energy and conservation equations for nanoperticles are transformed into a set of non-dimensional boundary layer equations along with the corresponding boundary conditions, which are then solved numerically using finite element method scheme based on the Galerkin method of weighted residuals. Results are presented in terms of streamlines, isotherms, iso-concentrations, average Nusselt number and average Sherwood number in the enclosure for different combinations of the governing parameters namely Reynolds number (Re), Richardson number (Ri), buoyancy ratio number (Br), Lewis number (Le),thermophoresis parameters (Nt) andBrownian motion parameters (Nb).This study has been conducted for different values of Re=50 to 500,Ri=0.1to 5,Le = 0.5to 3.0,Br = 0.1to 20,Nt =0.2 to 0.9 and Nb=0.2 to 1.0. The software MATLAB is used to perform computational purpose and the post processing software TECHPLOT has been used to exhibit the numerical results graphically. The results indicate that both the flow and the thermal fields strongly depend on the aforesaid parameters. Comparisons with previously published work are performed and the results are found to be in excellent agreement.