Thermodynamic Analysis for Buoyancy-Induced Couple Stress Nanofluid Flow with Constant Heat Flux

Adesanya, Samuel O.; Ogunseye, Hammed Abiodun; Falade, J.A.; Lebelo, Ramoshweu Solomon

doi:10.3390/e19110580

Cited by 15 publications

(11 citation statements)

References 34 publications

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“…We collected 12 papers in this special issue, covering both engineering applications [8][9][10][11][12] and fundamental studies [13][14][15][16][17][18][19] with respect to CFD of flow and heat transfer problems and interpretation of the CFD results with the SLA.…”

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confidence: 99%

“…The SLA was also intensively applied to fundamental studies, such as convective heat transfer problems [13][14][15][16][17][18]. Four papers among these studies are about forced convection: Ji et al [13] analyzed the entropy generation of fully-turbulent convective heat transfer of nano-fluids in a circular tube according to their RANS results.…”

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confidence: 99%

“…Two papers [17,18] are about natural or mixed convection. Adesanya et al [17] studied the entropy generation due to mixed convection in an inclined channel filled with porous media.…”

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confidence: 99%

“…Adesanya et al [17] studied the entropy generation due to mixed convection in an inclined channel filled with porous media. They argued that the coupled stresses and porous medium may reduce the entropy generation rate.…”

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confidence: 99%

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Second-Law Analysis: A Powerful Tool for Analyzing Computational Fluid Dynamics (CFD) Results

Jin

2017

Entropy

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Second-law analysis (SLA) is an important concept in thermodynamics, which basically assesses energy by its value in terms of its convertibility from one form to another. Highly-valued forms of energy in this context are called exergy, defined as those energies from which the maximum theoretical work is obtainable when the energy is interacting with the environment to equilibrium (see Moran et al. [1], for example).The counterpart of exergy, also called available work, is anergy, so that with this concept energy can generally be regarded as the sum of exergy and anergy. As a consequence of the second law of thermodynamics, exergy can be lost but cannot be created. Therefore, in a reversible process, exergy is preserved, whereas irreversibility (like losses in a flow field) leads to a loss of exergy (in favor of the corresponding increasing anergy).Losses in flow and heat transfer fields can, thus, be determined by their impact on the exergy, i.e., by determining the exergy losses. These losses of exergy are thermodynamically linked to the generation of entropy by the so-called Gouy Stodola theorem. It states that the lost exergy corresponds to the product of entropy generation and the environmental temperature (see, again, Moran et al. [1]).From a thermodynamic point of view, the quality of a flow or heat transfer process can be assessed by the entropy generation rate in this process (see Herwig [2]). However, entropy almost never appears in the textbooks of fluid dynamics and heat transfer (see, e.g., Batchelor, et al. [3] and Incropera, et al. [4]). This concept is widely ignored perhaps because the irreversibility effect is often fundamentally important in these two disciplines.After Bejan [5,6] laid the foundation with respect to analyzing and optimizing thermal systems with the SLA approach, the SLA of flow and heat transfer problems received more and more attention. Applying the SLA in computational fluid dynamics (CFD), Kock and Herwig [7] extended this concept to an in-depth analysis of turbulent flows and identified four different mechanisms of entropy generation: dissipation in a mean and fluctuating velocity field and heat flux in a mean and fluctuating temperature field. They also suggested how to calculate the entropy generation rates with the Reynolds Averaged Navier-Stokes (RANS) results. Herwig [2] stated that, with the help of the SLA, one may answer four important questions regarding a momentum and/or heat transfer process:• Which is the ideal process (no entropy generation)? • Where does entropy generation occur in a non-ideal process? • Why does entropy generation occur at a certain location and with certain strength? • How can entropy generation be reduced overall or locally?The purpose of this special issue is to demonstrate how the CFD results can be better interpreted by the SLA. We collected 12 papers in this special issue, covering both engineering applications [8-12] and

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confidence: 99%

mentioning

confidence: 99%

“…Two papers [17,18] are about natural or mixed convection. Adesanya et al [17] studied the entropy generation due to mixed convection in an inclined channel filled with porous media.…”

mentioning

confidence: 99%

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confidence: 99%

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Second-Law Analysis: A Powerful Tool for Analyzing Computational Fluid Dynamics (CFD) Results

Jin

2017

Entropy

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“…Some authors have investigated entransy dissipation [14][15][16][17][18][19]. The entropy generation in the flow of an electrically conducting couple stress nanofluid through a vertical porous channel subjected to constant heat flux was investigated in [20]. Entransy of an object is the heat transfer ability during a given time period, while entransy dissipation is essentially the thermomass energy dissipation during heat transfer.…”

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confidence: 99%

Entransy Dissipation Analysis and New Irreversibility Dimension Ratio of Nanofluid Flow Through Adaptive Heating Elements

Alic

2019

Energies

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A hollow electric heating cylinder is inserted inside a thermo-insulating cylindrical body of larger diameter, together representing a single cylindrical heating element. Three cylindrical heating elements, with an independent electrical source, are arranged alternately one after the other to form a heating duct. The internal diameters of the hollow heating cylinders are different, and the cylinders are arranged from the largest to the smallest in the nanofluid’s flow direction. Through these hollow heating cylinders passes nanofluid, which is thereby heated. The material of the hollow heating cylinders is a PTC (positive temperature coefficient) heating source, which allows maintaining approximately constant temperatures of the cylinders’ surfaces. The analytical analysis used three temperatures of the hollow heating cylinders of 400 K, 500 K, and 600 K. The temperatures of the heating cylinders are varied for each of the three cylindrical heating elements. In the same arrangement, the inner diameters of the hollow cylinders are set to 15 mm, 11 mm, and 7 mm in the nanofluid’s flow direction. The basis of the analytical model is the entransy flow dissipation rate. Furthermore, a new dimension irreversibility ratio is introduced as the ratio between entransy flow dissipation and thermal-generated entropy. This paper provides a suitable basis for optimizing the geometric and process parameters of cylindrical heating elements. An optimization criterion can be maximizing the new dimensionless irreversibility ratio, which implies minimizing thermal entropy and maximizing entransy flow dissipation.

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Influence of Thermophoresis and Brownian Motion on MHD Mixed Convective Chemically Reacting Couple Stress Fluid Flow in Porous Medium Between Parallel Plates

Jawalkar

Ojjela

Pradhan

2020

Mathematical Modeling and Computational Tools

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Thermodynamic Analysis for Buoyancy-Induced Couple Stress Nanofluid Flow with Constant Heat Flux

Cited by 15 publications

References 34 publications

Second-Law Analysis: A Powerful Tool for Analyzing Computational Fluid Dynamics (CFD) Results

Second-Law Analysis: A Powerful Tool for Analyzing Computational Fluid Dynamics (CFD) Results

Entransy Dissipation Analysis and New Irreversibility Dimension Ratio of Nanofluid Flow Through Adaptive Heating Elements

Influence of Thermophoresis and Brownian Motion on MHD Mixed Convective Chemically Reacting Couple Stress Fluid Flow in Porous Medium Between Parallel Plates

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