How to Teach Heat Transfer More Systematically by Involving Entropy

Herwig, Heinz

doi:10.3390/e20100791

Cited by 7 publications

(5 citation statements)

References 20 publications

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“…We verified the consistency of the schemes in Equation (15) and Equation (19) using ξ = 1. The first order is found exact in time, while the second order is correct in space, in agreement with the schemes reported in [30]. By using ξ = 0.5, we were able to enhance the accuracy of the scheme in time up to second order.…”

Section: Finite Difference Methodssupporting

confidence: 87%

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Heat transfer in an unsteady vertical porous channel with injection/suction in the presence of heat generation

Obalalu

Wahaab

Adebayo

2020

Journal of Taibah University for Science

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This paper studies convective heat transfer in an unsteady vertical porous channel with suction/injection in the presence of heat generation. A semi-implicit finite difference method was employed to solve the Cartesian coordinate forms of the governing equations. Subsequently, the entropy generation number for varying values of intrinsic parameters, as well as the temperature and velocity profile, Bejan number and irreversibility of the system were successfully calculated. We observed that the convective cooling by suction is more effective on thermal properties than injection convective cooling. Hence, the process of entropy can be enhanced by convective heat transfer and viscous dissipation. ARTICLE HISTORY

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Section: Finite Difference Methodssupporting

confidence: 87%

“…The theoretical and practical understanding of entropy generation has been intensely considered in flow analysis [12,30]. Entropy generation is the amount of strength disoriented when performing the fundamental of convection heat.…”

Section: Entropy Generation Ratementioning

confidence: 99%

Heat transfer in an unsteady vertical porous channel with injection/suction in the presence of heat generation

Obalalu

Wahaab

Adebayo

2020

Journal of Taibah University for Science

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“…Energy and mass balances must also be carefully evaluated; thus, the conversion of biomass and the development of circular cycles should consider energetic constraints [8]. Absolute circularity is not achievable due to restrictions dictated by the second thermodynamic law since some energy is unavoidably lost [9].…”

Section: Introductionmentioning

confidence: 99%

Syngas Fermentation: Cleaning of Syngas as a Critical Stage in Fermentation Performance

Ellacuriaga,

Gil,

Gómez

2023

Fermentation

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The fermentation of syngas is an attractive technology that can be integrated with gasification of lignocellulosic biomass. The coupling of these two technologies allows for treating a great variety of raw materials. Lignin usually hinders microbial fermentations; thus, the thermal decomposition of the whole material into small molecules allows for the production of fuels and other types of molecules using syngas as substrate, a process performed at mild conditions. Syngas contains mainly hydrogen, carbon monoxide, and carbon dioxide in varying proportions. These gases have a low volumetric energy density, resulting in a more interesting conversion into higher energy density molecules. Syngas can be transformed by microorganisms, thus avoiding the use of expensive catalysts, which may be subject to poisoning. However, the fermentation is not free of suffering from inhibitory problems. The presence of trace components in syngas may cause a decrease in fermentation yields or cause a complete cessation of bacteria growth. The presence of tar and hydrogen cyanide are just examples of this fermentation’s challenges. Syngas cleaning impairs significant restrictions in technology deployment. The technology may seem promising, but it is still far from large-scale application due to several aspects that still need to find a practical solution.

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“…It is important to minimize the entropy generation in any engineering process. The numerical ratio of the entropy generation due to thermal irreversibility to the total entropy generation [42][43][44][45][46][47][48], termed as the Bejan number [49,50], is investigated in this paper.…”

Section: Introductionmentioning

confidence: 99%

Mathematical modeling of graphene–PDMS Maxwell nanofluid flow over a stretching surface: A study on the efficient energy management^†

2023

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This study investigates the unsteady Maxwell nanofluid flow past a stretching surface, embedded in a porous medium, in the presence of magnetic field and thermal radiation effects. Polydimethylsiloxane (PDMS) is considered as a Maxwell base fluid and graphene is taken as nanoparticle to form the nanofluid. It is a well‐reported fact in the literature (Boland et al. Science, 354(2016)1257) that viscous graphene polymers can be used to make sensitive electromechanical sensors, thereby setting the direction and incentive for the study of graphene–PDMS nanofluid. In this paper, we have implemented the Navier's slip boundary condition at the nanofluid‐surface interface. Entropy analysis for the energy efficiency of the system in terms of the Bejan number is carried out extensively. By employing suitable similarity transformations, the set of partial differential equations has been transformed into a set of ordinary differential equations. The transformed equations are solved by the homotopy analysis method (HAM). The nanofluid velocity, temperature, skin‐friction coefficient, and heat transfer rate are analyzed in this paper under several regulatory physical parameters. The findings show that the rise in time relaxation parameter has adverse effects on nanofluid velocity but enhances the entropy generation in the system. The heat transfer rate decreases with an enhancement of the Deborah number but increases with a rise in the nanoparticle volume fraction. The Bejan number shows increasing trend with an enhancement of unsteady parameter, nanoparticle volume fraction, and porous permeability parameter. This study bears the potential application in powder technology, plastic extrusion process, as well as in bio‐engineering.

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How to Teach Heat Transfer More Systematically by Involving Entropy

Cited by 7 publications

References 20 publications

Heat transfer in an unsteady vertical porous channel with injection/suction in the presence of heat generation

Heat transfer in an unsteady vertical porous channel with injection/suction in the presence of heat generation

Syngas Fermentation: Cleaning of Syngas as a Critical Stage in Fermentation Performance

Mathematical modeling of graphene–PDMS Maxwell nanofluid flow over a stretching surface: A study on the efficient energy management^†

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How to Teach Heat Transfer More Systematically by Involving Entropy

Cited by 7 publications

References 20 publications

Heat transfer in an unsteady vertical porous channel with injection/suction in the presence of heat generation

Heat transfer in an unsteady vertical porous channel with injection/suction in the presence of heat generation

Syngas Fermentation: Cleaning of Syngas as a Critical Stage in Fermentation Performance

Mathematical modeling of graphene–PDMS Maxwell nanofluid flow over a stretching surface: A study on the efficient energy management†

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Product

Resources

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Mathematical modeling of graphene–PDMS Maxwell nanofluid flow over a stretching surface: A study on the efficient energy management^†