Entropy generation and natural convection of nanoparticle-water mixture (nanofluid) near water density inversion in an enclosure with various patterns of vertical wavy walls

Kashani, Sina; Ranjbar, A.A.; Mastiani, Mohammad; Mirzaei, Hooshyar

doi:10.1016/j.amc.2013.10.054

Cited by 31 publications

(10 citation statements)

References 24 publications

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“…Increasing functions of entropy generation with the size of the solid insertion and the volume fraction of the nanoparticles were declared. However, the following citations are examples for the case of analyzing the thermodynamic irreversibility in nanofluids; Kashani et al [ 44 ]; Cho et al [ 45 ]; Ting et al [ 46 ]; Ismael et al [ 47 ]; Cho et al [ 48 ]; Chamkha et al [ 49 ]; Chamkha et al [ 50 ]; Rashidi et al [ 51 ]; Qasim et al [ 52 ]; Darbari et al [ 53 ] and Kefayati and Tang [ 54 ]. Very recently, Alsabery et al [ 55 ] have studied the entropy generation inside a porous cavity with wavy walls including a rotating cylinder.…”

Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Mixed Convection and Entropy Generation in a Wavy-Walled Cavity Filled with Nanofluid and Involving a Rotating Cylinder

Alsabery

Ismael

Chamkha

et al. 2018

Entropy

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This numerical study considers the mixed convection and the inherent entropy generated in Al 2 O 3 –water nanofluid filling a cavity containing a rotating conductive cylinder. The vertical walls of the cavity are wavy and are cooled isothermally. The horizontal walls are thermally insulated, except for a heat source segment located at the bottom wall. The dimensionless governing equations subject to the selected boundary conditions are solved numerically using the Galerkin finite-element method. The study is accomplished by inspecting different ranges of the physical and geometrical parameters, namely, the Rayleigh number ( 10 3 ≤ R a ≤ 10 6 ), angular rotational velocity ( 0 ≤ Ω ≤ 750 ), number of undulations ( 0 ≤ N ≤ 4 ), volume fraction of Al 2 O 3 nanoparticles ( 0 ≤ ϕ ≤ 0.04 ), and the length of the heat source ( 0.2 ≤ H ≤ 0.8 ) . The results show that the rotation of the cylinder boosts the rate of heat exchange when the Rayleigh number is less than 5 × 10 5 . The number of undulations affects the average Nusselt number for a still cylinder. The rate of heat exchange increases with the volume fraction of the Al 2 O 3 nanoparticles and the length of the heater segment.

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Section: Introductionmentioning

confidence: 99%

Numerical Investigation of Mixed Convection and Entropy Generation in a Wavy-Walled Cavity Filled with Nanofluid and Involving a Rotating Cylinder

Alsabery

Ismael

Chamkha

et al. 2018

Entropy

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“…Additionally, high values of Rayleigh numbers increased total entropy generation and the Nusselt number. Kashani et al [ 33 ] performed numerical simulations of the natural convection of a nanofluid in a two-dimensional cavity with corrugated walls. They found that flow, heat transfer, and entropy generation were affected by density variation and nanoparticle dispersion.…”

Section: Introductionmentioning

confidence: 99%

Numerical Study of Nanofluid Irreversibilities in a Heat Exchanger Used with an Aqueous Medium

Ovando-Chacon¹,

Ovando-Chacón

León³

et al. 2020

Entropy

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Heat exchangers play an important role in different industrial processes; therefore, it is important to characterize these devices to improve their efficiency by guaranteeing the efficient use of energy. In this study, we carry out a numerical analysis of flow dynamics, heat transfer, and entropy generation inside a heat exchanger; an aqueous medium used for oil extraction flows through the exchanger. Hot water flows on the shell side; nanoparticles have been added to the water in order to improve heat transfer toward the cold aqueous medium flowing on the tube side. The aqueous medium must reach a certain temperature in order to obtain its oil extraction properties. The analysis is performed for different Richardson numbers (Ri = 0.1–10), nanofluid volume fractions (φ = 0.00–0.06), and heat exchanger heights (H = 0.6–1.0). Results are presented in terms of Nusselt number, total entropy generation, Bejan number, and performance evaluation criterion. Results showed that heat exchanger performance increases with the increase in Ri when Ri > 1 and when reducing H.

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“…Following Bejan's conclusions from these books, several studies have been published in this topic under different engineering circumstances. An analysis of entropy generation in enclosures with and without a nanofluid can be found in several past studies [29][30][31][32][33][34][35][36][37]. These studies recorded an increase in entropy generation with an increasing ratio of inertial to viscous forces, while there was conflict between heat transfer irreversibility and the volume fraction of nanoparticles.…”

Section: Introductionmentioning

confidence: 99%

Mixed Convection and Entropy Generation of an Ag-Water Nanofluid in an Inclined L-Shaped Channel

et al. 2019

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This paper investigates the mixed convection and entropy generation of an Ag-water nanofluid in an L-shaped channel fixed at an inclination angle of 30° to the horizontal axis. An isothermal heat source was positioned in the middle of the right inclined wall of the channel while the other walls were kept adiabatic. The finite volume method was used for solving the problem’s governing equations. The numerical results were obtained for a range of pertinent parameters: Reynolds number, Richardson number, aspect ratio, and the nanoparticles volume fraction. These results were Re = 50–200; Ri = 0.1, 1, 10; AR = 0.5–0.8; and φ = 0.0–0.06, respectively. The results showed that both the Reynolds and the Richardson numbers enhanced the mean Nusselt number and minimized the rate of entropy generation. It was also found that when AR. increased, the mean Nusselt number was enhanced, and the rate of entropy generation decreased. The nanoparticles volume fraction was predicted to contribute to increasing both the mean Nusselt number and the rate of entropy generation.

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Entropy generation and natural convection of nanoparticle-water mixture (nanofluid) near water density inversion in an enclosure with various patterns of vertical wavy walls

Cited by 31 publications

References 24 publications

Numerical Investigation of Mixed Convection and Entropy Generation in a Wavy-Walled Cavity Filled with Nanofluid and Involving a Rotating Cylinder

Numerical Investigation of Mixed Convection and Entropy Generation in a Wavy-Walled Cavity Filled with Nanofluid and Involving a Rotating Cylinder

Numerical Study of Nanofluid Irreversibilities in a Heat Exchanger Used with an Aqueous Medium

Mixed Convection and Entropy Generation of an Ag-Water Nanofluid in an Inclined L-Shaped Channel

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