Numerical study of the chaotic flow in three-dimensional open geometry and its effect on the both fluid mixing and heat performances

Abstract

In this study, we investigate the chaotic behavior of fluid particles in three-dimensional open geometries and their effects on the amelioration of miscible fluids mixing, thermal homogenization and thermal performances by using a computational fluid dynamics (CFD) method. Three geometry configurations (straight channel, serpentine-2D channel and chaotic geometry channel serpentine-3D) are considered. The dispersion phenomena are characterized through the presentation of the Poincaré sections and the mixing quality is quantified by calculating the mixing degree in cross section for several Reynolds numbers ranging from 5 to 200. This study reveals that height capacities in terms of mixing and heat performances are obtained by the chaotic geometry where the level mixing is superior to 0.95 for Reynolds equal to 200. In addition, the heat transfer in the S-3D is highly improved where the mean Nusselt number is 13 times bigger than that calculated in the straight channel.

Modeling the interaction of coolant flows at the liquid-solid boundary with allowance for the laminar boundary layer

“…After analyzing the literature sources, we came to the conclusion that the rate of heat exchange in liquid refrigerants through the laminar boundary layer (LBL) depends on the following main factors: -laminar flow is responsible for the turbulent flow, but is less energy-efficient [2,4]; -LBL, namely its average thickness is responsible for the total thermal resistance of the system [5,6]; -the thermal resistance depends on the coefficient of surface tension of the refrigerant [7]; -the intensity of heat exchange depends on the hydrophilicity or hydrophobicity of the wetting surface [8];…”

“…To increase the heat transfer coefficients in heat exchangers, various methods are used, in particular, the modification of the structural elements of boilers and other equipment [1], the increase in the turbulence of the refrigerant flows [2], the use of liquids with the optimal concentration of surfactants (SAS). For example, the maximum rate of heat exchange was observed when a nonionic surfactant was added to water [3].…”

Presentation and Performance of a Planar Solid Oxide Fuel Cell with Chaotic Gas Channels

“…It was found that the mixing of the materials in the channel was facilitated by the chaotic advection generated in the C‐shaped channel, and the distribution of the material in the channel was thus more uniform. Boukhalkhal et al [ 22 ] compared numerically the effect of geometry configurations (straight channel, serpentine 2D channel, and chaotic geometry channel serpentine‐3D) and the results showed that height capacities in terms of mixing and heat performances are obtained by the chaotic geometry. Moreno‐Blanco et al [ 23 ] analyzed the overpotentials inherent during the operation of a SOFC and found the performance of SOFC is affected by the ratio between the gas channel–electrode interface area and the active area.…”

Similarity and numerical solutions for the Lévêque problem of boundary layer heat and mass transfer in Hagen-Poiseuille flow

“…Several researchers have investigated several aspects of the convective flow problems under different flow conditions [4]. However, all the studies above are limited to the Newtonian case in which the classical Navier -Stokes equation is valid [5]. Ambethkar and Kumar [6] used the stream function-vorticity formulation to solve the governing equations of 2-D unsteady viscous incompressible flow along with no-slip and slip wall boundary conditions.…”