Entropy Generation at Natural Convection in an Inclined Rectangular Cavity

Abstract:The purpose of the current investigation was to discuss the entropy generation analysis for a carbon nanotube (CNT) suspension nanofluid in a plumb duct with peristalsis. The entropy generation number due to heat transfer and fluid friction is formulated. The velocity and temperature distributions across the tube are presented along with pressure attributes. Exact analytical solution for velocity and temperature profile are obtained. It is found that the entropy generation number attains high values in the region close to the walls of the tube, while it attains low values near the center of the tube.

Section: Viscous Dissipation and Entropy Generationmentioning

confidence: 99%

“…Entropy generation due to heat and fluid flow in backward facing step flow with various expansion ratios was studied by Abu-Nada [19]. Further analysis can be found [20][21][22][23][24].…”

Section: Introductionmentioning

confidence: 99%

Entropy Generation Analysis for a CNT Suspension Nanofluid in Plumb Ducts with Peristalsis

Akbar

2015

“…Mahmud and Sadrul Islam [5] applied the second law of thermodynamics to predict the nature of irreversibility in inclined wavy wall cavity. Bouabid et al [6] studied the transient state study of entropy generation in inclined cavity with various aspect ratios. Cheng and Liang [7] concluded that the applicability of the entropy generation minimization to optimize thermodynamic systems is conditional if the maximum output power is the objective.…”

Section: Introductionmentioning

confidence: 99%

Entropy Generation and Natural Convection of CuO-Water Nanofluid in C-Shaped Cavity under Magnetic Field

Chamkha

Ismael

Kasaeipoor

et al. 2016

130

This paper investigates the entropy generation and natural convection inside a C-shaped cavity filled with CuO-water nanofluid and subjected to a uniform magnetic field. The Brownian motion effect is considered in predicting the nanofluid properties. The governing equations are solved using the finite volume method with the SIMPLE (Semi-Implicit Method for Pressure Linked Equations) algorithm. The studied parameters are the Rayleigh number (1000 ď Ra ď 15,000), Hartman number (0 ď Ha ď 45), nanofluid volume fraction (0 ď φ ď 0.06), and the cavity aspect ratio (0.1 ď AR ď 0.7). The results have shown that the nanoparticles volume fraction enhances the natural convection but undesirably increases the entropy generation rate. It is also found that the applied magnetic field can suppress both the natural convection and the entropy generation rate, where for Ra = 1000 and φ = 0.04, the percentage reductions in total entropy generation decreases from 96.27% to 48.17% for Ha = 45 compared to zero magnetic field when the aspect ratio is increased from 0.1 to 0.7. The results of performance criterion have shown that the nanoparticles addition can be useful if a compromised magnetic field value represented by a Hartman number of 30 is applied.

“…They have considered the effects of heat transfer irreversibility and fluid friction irreversibility on the entropy generation and had analyzed the transient behavior of the entropy generation in the studied cavity. Bounabid et al [7] analyzed the transient entropy generation of natural convection in an inclined rectangular cavity comprising vertical isothermal walls and adiabatic horizontal walls. Their results have shown that the entropy generation increased with the increases of Grashof number, irreversibility distribution ratio and aspect ratio of the cavity.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation into Natural Convection and Entropy Generation in a Nanofluid-Filled U-Shaped Cavity

Cho

Yau

Chiu

et al. 2015

Abstract:This current work studies the heat transfer performance and entropy generation of natural convection in a nanofluid-filled U-shaped cavity. The flow behavior and heat transfer performance in the cavity are governed using the continuity equation, momentum equations, energy equation and Boussinesq approximation, and are solved numerically using the finite-volume method and SIMPLE C algorithm. The simulations examine the effects of the nanoparticle volume fraction, Rayleigh number and the geometry parameters of the U-shaped cavity on the mean Nusselt number and total entropy generation. It shows that the mean Nusselt number increases and the total entropy generation reduces as the volume fraction of nanoparticles increases. In addition, the results show that the mean Nusselt number and the total entropy generation are both increased as the Rayleigh number increases. Finally, it also shows that mean Nusselt number can be increased and the total entropy generation can be reduced by extending the length of the low temperature walls or widening the width of the low temperature walls.