Thermo-entropy analysis of water-FMWCNT nano-fluid flow in a backward-facing channel with obstacle

Abstract

Thermo hydraulic analysis of nano-fluid flow phenomena through backward-facing channel has currently gained attention of the researchers, and is applied in a variety of engineering applications. Hydro-thermal properties of water/FMWCNT nano-fluid flow in a backward-facing channel embedded with an obstacle under uniform heat flux have been studied numerically with the variations in the values of Reynolds numbers [Formula: see text] weight percentage of carbon nano-particle [Formula: see text] and differently shaped obstacles. The governing equations (continuity, x-momentum, y-momentum, and energy) have been solved using the finite volume approach, and fluent software has been used to visualize the simulation results. Impact of various forms of obstacle (plane, elliptical, and triangular), the ratio of obstacle height to width (A/B), the ratio of obstacle pitch to width [Formula: see text], [Formula: see text], and the values of [Formula: see text] on the different rheological behaviour of nano-fluid flow have been investigated. For all the forms of obstacle configuration, the distributions of velocity streamlines, temperature contours, absolute pressure drop [Formula: see text], average friction factor [Formula: see text], local Nusselt number [Formula: see text], skin friction coefficients [Formula: see text], average Nusselt number ([Formula: see text]), and pumping power ([Formula: see text]) have been demonstrated for several values of [Formula: see text] and [Formula: see text], and [Formula: see text] and [Formula: see text]. For several values of [Formula: see text] and [Formula: see text], generations of frictional entropy [Formula: see text], thermal entropy [Formula: see text], and Bejan number [Formula: see text] have been explored. It seems that the presence of obstacle, and the increase in the values of [Formula: see text], [Formula: see text] causes the rise of the values of [Formula: see text], and [Formula: see text] than the case of smooth channel. Moreover, at [Formula: see text] and [Formula: see text], it has been found that the [Formula: see text] increase in [Formula: see text] becomes [Formula: see text] in the case of backward-facing channel with plane obstacle (A/B = 1) as compared to the case of smooth channel. Furthermore, at a constant value of [Formula: see text] it has been found that the generation of [Formula: see text] decreases but the generation of [Formula: see text] entropy increases with the rise in the values of [Formula: see text].

Keywords

• Heat transfer rate
• Pressure drop
• Generation of entropy
• Laminar flow
• reynolds number