Analysis of heat transfer in SWCNTs-ethylene glycol-based nanofluid past a vertical complex wavy surface

Abstract

In this paper, the improvement of heat transfer in SWCNTs (Single wall carbon nanotubes) ethylene glycol (EG)-based nanofluid through a complex (irregular) surface is examined. A complex surface is created as a sum of two sine functions in term of fundamental wave and its first harmonic wave. The modeled nonlinear governing equations are made dimensionless PDEs by introducing scaling variables. The resulting nonlinear PDEs are solved numerically using implicit scheme base on backward and central difference approximations. A study of heat transfer is performed in three different ways namely nanofluid flow along flat plate, flow along single sinusoidal surface and complex surface. To check in which case rate of heat transfer increases, the graphs of local Nusselt number, rate of total heat transfer and average Nusselt number are plotted. From these graphs, it is noticed that total heat transfer rate and Nusselt numbers of SWCNTs-based nanofluid increase as compared to base fluid. Also total heat transfer rate for both EG base fluid and nanofluid increases along complex surface as compared to single sinusoidal surface and opposite behavior is observed in Nusselt numbers. It is seen that by adding SWCNTs in EG base fluid, heat transfer rate increases 60% in case of dominant amplitude of fundamental wave and 88% to 98% approximately in case of dominant amplitude of harmonic wave w.r.t. the case of $$\chi = 0.0,\,\alpha_{1} = 0.5,\,\alpha_{2} = 0.2.$$