Entropy generation analysis of turbulent convection flow of Al2O3–water nanofluid in a circular tube subjected to constant wall heat flux

Abstract:The entropy generation based on the second law of thermodynamics is investigated for turbulent forced convection flow of ZrO2-water nanofluid through a square pipe with constant wall heat flux. Effects of different particle concentrations, inlet conditions and particle sizes on entropy generation of ZrO2-water nanofluid are studied. Contributions from frictional and thermal entropy generations are investigated, and the optimal working condition is analyzed. The results show that the optimal volume concentration of nanoparticles to minimize the entropy generation increases when the Reynolds number decreases. It was also found that the thermal entropy generation increases with the increase of nanoparticle OPEN ACCESSEntropy 2014, 16 6117 size whereas the frictional entropy generation decreases. Finally, the entropy generation of ZrO2-water was compared with that from other nanofluids (including Al2O3, SiO2 and CuO nanoparticles in water). The results showed that the SiO2 provided the highest entropy generation.

Section: Effect Of Different Nanoparticlessupporting

confidence: 66%

“…In the present work, the entropy generation of ZrO2, CuO, SiO2 and Al2O3 nanofluids in a square duct was studied using the using the approach of Bianco et al [37]. The nanofluid flows were in a turbulent forced convection regime with a constant wall heat flux.…”

mentioning

confidence: 99%

Entropy Generation during Turbulent Flow of Zirconia-water and Other Nanofluids in a Square Cross Section Tube with a Constant Heat Flux

Yarmand

Ahmadi

Gharehkhani

et al. 2014

“…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%

“…The first part is the entropy generation due to finite temperature difference (Nscond) and the second part is the entropy generation due to viscous effects (Nsvisc). The Bejan number is defined as [17][18][19][20][21][22][23][24] . …”

Section: Viscous Dissipation and Entropy Generationmentioning

confidence: 99%

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

Akbar

2015

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.

“…He showed that by minimizing the entropy, the efficiency of a thermal system could be enhanced based on the Second Law of Thermodynamics. Thereafter, several authors [42][43][44][45][46][47][48][49][50][51] have analyzed different problems to study the entropy effects on thermal systems and to find ways to minimize them. Considering all the above, the goal of the current research was to optimize the steady state fully developed mixed convection incompressible flow in a vertical microchannel such that the walls of the channels are subjected to different wall temperatures and the Rosseland approximation model.…”

Section: Introductionmentioning

confidence: 99%

Optimal Design of Magnetohydrodynamic Mixed Convection Flow in a Vertical Channel with Slip Boundary Conditions and Thermal Radiation Effects by Using an Entropy Generation Minimization Method

Jamalabadi

Park

Lee

2015

Abstract:Investigation of the effect of thermal radiation on a fully developed magnetohydrodynamic (MHD) convective flow of a Newtonian, incompressible and electrically conducting fluid in a vertical microchannel bounded by two infinite vertical parallel plates with constant temperature walls through a lateral magnetic field of uniform strength is presented. The Rosseland model for the conduction radiation heat transfer in an absorbing medium and two plates with slip-flow and no-slip conditions are assumed. In addition, the induced magnetic field is neglected due to the assumption of a small magnetic Reynolds number. The non-dimensional governing equations are solved numerically using Runge-Kutta-Fehlberg method with a shooting technique. The channel is optimized based on the Second Law of Thermodynamics by changing various parameters such as the thermal radiation parameter, the temperature parameter, Hartmann number, Grashof to Reynolds ratio, velocity slip length, and temperature jump.