Effect of cylinder geometry on the heat transfer enhancement of power-law fluid flow inside a channel

Abstract

The heat transfer enhancement and pressure drop of non-Newtonian power-law fluid flow due to the presence of a bluff body inside a channel are numerically investigated. Different cross-section geometries such as circular, elliptical, trapezoidal, and inclined square cylinders with the angles of 0°, 15°, 30°, and 45° are studied and compared with straight channel. The results are presented as streamlines, local and average Nusselt number, friction factor and thermo-hydraulic performance for the Reynolds number of 10, 20, and 30, Prandtl number of 100, and power-law index of 0.4, 0.6, 0.8, and 1. The blockage ratio is considered as 0.25 for all the cases. The results show that the thermo-hydraulic performance increases by decreasing the power-law index and the square cylinder with inclined angle of 45° has maximum thermo-hydraulic performance. The effect of the cylinder geometry on the heat transfer enhancement was more than that of the power-law index.

Flow of power-law fluid past a circular cylinder in the vicinity of a moving wall

“…For complement, the fluid rheology property is also taken into account. Among the non-Newtonian fluid, the power-law fluid is a kind of typical fluid because its rheological property such as shear-shinning and shear-thickening has an effect on free convection [17], natural convection [18], and heat transfer enhancement [19]. Therefore, the purpose of this paper is to study the hydrodynamic coefficient, gap flow characteristics, and recirculation mode for the steady flow of power-law fluid with different power-law indices over a circular cylinder near a moving wall for different gap ratios and explain the formation mechanism by investigating the vortex characteristics in the wake behind the cylinder.…”

Thermal performance optimization of a sinusoidal wavy channel with different phase shifts using artificial bee colony algorithm

“…A vast amount of numerical and experimental research in the last decade has been performed, with utilizing wavy walls or corrugations as a passive method to increase heat transfer in many engineering applications, particularly those employing compact heat exchangers. As a matter of fact, corrugated channels such as sinusoidal, triangular and trapezoidal prevent the development of flow by disturbing the flow field and boundary layer and improve the mixing of higher and lower temperature parts which enhance the heat transfer [1][2][3][4]. Many researchers studied the effect of sinusoidal wavy wall on heat transfer of conventional fluid, some of which will be described here.…”