Nanofluid Convective Heat Transfer Enhancement Elliptical Tube inside Circular Tube under Turbulent Flow

Abstract

Heat transfer enhancement employing an elliptical tube inside a circular tube to increase the heat transfer rate without increasing in pressure drop is investigated. The flow rate inside the narrow is in the range of Reynolds number 10,000 to 100,000. Commercial software is used to solve the governing equations (continuity, momentum, and energy) by adopting a finite volume method (FVM). The electrical heater is connected around the circular tube to apply uniform heat flux (3000 W/m2) as a boundary condition. The volume concentrations are in the range of 0.25% to 1% with different TiO2 nanoparticle diameters in the range of 27 nm to 50 nm dispersed in water. The results indicate that the elliptical annulus tube can enhance heat transfer and friction factor by approximately 19% and 6% than the circular tube respectively. Results show that the heat transfer enhancement is significantly increasing as the volume concentrations increase and the nanoparticles size diameter decrease.

Nanofluids in Zigzag Elliptical Tube Heat Exchanger: A Design Perspective

“…Another form of the tube design is elliptical tube inside a circular tube. The elliptical annulus tube may improve the friction factor and heat transmission by 6 and 19%, respectively when compared to circular annulus [12], [57]. The Nusselt number and friction factor often increased with decreasing particle diameter but increased with volume concentration.…”

“…Conversely, Kumar [11] reported the improvement of heat transfer by Al2O3 nanofluid at low volume fraction under turbulent flow inside a pipe of constant wall temperature. In a related work, Danook et al [12] evaluated the heat transfer of nanofluid at Reynolds number between 1×10 4 and 1×10 5 , as a specific transition from laminar to turbulent flow regime.…”

Effects of Convection on Sisko Fluid with Peristalsis in an Asymmetric Channel

“…Heat transfer with convective boundary conditions is implicated in mechanisms like gas turbines, thermal energy storage, nuclear power plants etc.. In this context, some recent studies [26][27][28][29][30][31] are observed in which the study of non-Newtonian fluid flows with peristalsis are conducted in the vicinity of convective conditions.…”