scholarly journals Numerical study on transient local entropy generation in pulsating turbulent flow through an externally heated pipe

Sadhana ◽  
2005 ◽  
Vol 30 (5) ◽  
pp. 625-648 ◽  
Author(s):  
Hüseyİn Yapici ◽  
Gamze Baştürk ◽  
Nesrİn KayataŞ ◽  
Şenay Yalçin
Keyword(s):  
Turbulent Flow ◽  
Entropy Generation ◽  
Numerical Study ◽  
Local Entropy ◽  
Flow Through ◽  
Local Entropy Generation

scholarly journals Numerical Study On Local Entropy Generation In Compressible Flow Through A Suddenly Expanding Pipe

Entropy ◽  
2005 ◽  
Vol 7 (1) ◽  
pp. 38-67 ◽  
Author(s):  
Hüseyin Yapici ◽  
Nesrin Kayatas ◽  
Nafiz Kahraman ◽  
Gamze Bastürk
Keyword(s):  
Compressible Flow ◽  
Entropy Generation ◽  
Numerical Study ◽  
Local Entropy ◽  
Flow Through ◽  
Local Entropy Generation

scholarly journals Numerical study of effect of oxygen fraction on local entropy generation in a methane-air burner

Sadhana ◽  
2004 ◽  
Vol 29 (6) ◽  
pp. 641-667 ◽  
Author(s):  
Huseyin Yapici ◽  
Gamze Basturk ◽  
Nesrin Kayatas ◽  
Bilge Albayrak
Keyword(s):  
Entropy Generation ◽  
Numerical Study ◽  
Local Entropy ◽  
Oxygen Fraction ◽  
Effect Of Oxygen ◽  
Local Entropy Generation

Numerical study of local entropy generation in a heated turbulent plane jet developing in a co-flowing stream

2018 ◽  
Vol 62 ◽  
pp. 605-628 ◽  
Author(s):  
Amel Elkaroui ◽  
Syrine Ben Haj Ayech ◽  
Mohamed Hichem Gazzah ◽  
Nejla Mahjoub Saïd ◽  
Georges Le Palec
Keyword(s):  
Entropy Generation ◽  
Numerical Study ◽  
Local Entropy ◽  
Turbulent Plane ◽  
Plane Jet ◽  
Flowing Stream ◽  
Local Entropy Generation

Study on transient local entropy generation in pulsating fully developed laminar flow through an externally heated pipe

2006 ◽  
Vol 43 (1) ◽  
pp. 17-35 ◽  
Author(s):  
Hüseyin Yapıcı ◽  
Nesrin Kayataş ◽  
Gamze Baştürk ◽  
Nafiz Kahraman
Keyword(s):  
Laminar Flow ◽  
Entropy Generation ◽  
Local Entropy ◽  
Flow Through ◽  
Local Entropy Generation

Numerical study on local entropy generation in a burner fueled with various fuels

2005 ◽  
Vol 41 (6) ◽  
pp. 519-534 ◽  
Author(s):  
Hüseyin Yapici ◽  
Nesrin Kayataş ◽  
Bilge Albayrak ◽  
Gamze Baştürk
Keyword(s):  
Entropy Generation ◽  
Numerical Study ◽  
Local Entropy ◽  
Local Entropy Generation

scholarly journals Non-Newtonian effect on heat transfer and entropy generation of natural convection nanofluid flow inside a vertical wavy porous cavity

2021 ◽  
Vol 3 (3) ◽  
Author(s):  
Mahbuba Tasmin ◽  
Preetom Nag ◽  
Zarin T. Hoque ◽  
Md. Mamun Molla
Keyword(s):  
Heat Transfer ◽  
Natural Convection ◽  
Entropy Generation ◽  
Power Law ◽  
Volume Fraction ◽  
Local Entropy ◽  
Nanofluid Flow ◽  
Porosity Level ◽  
Power Law Index ◽  
Local Entropy Generation

AbstractA numerical study on heat transfer and entropy generation in natural convection of non-Newtonian nanofluid flow has been explored within a differentially heated two-dimensional wavy porous cavity. In the present study, copper (Cu)–water nanofluid is considered for the investigation where the specific behavior of Cu nanoparticles in water is considered to behave as non-Newtonian based on previously established experimental results. The power-law model and the Brinkman-extended Darcy model has been used to characterize the non-Newtonian porous medium. The governing equations of the flow are solved using the finite volume method with the collocated grid arrangement. Numerical results are presented through streamlines, isotherms, local Nusselt number and entropy generation rate to study the effects of a range of Darcy number (Da), volume fractions (ϕ) of nanofluids, Rayleigh numbers (Ra), and the power-law index (n). Results show that the rate of heat transfer from the wavy wall to the medium becomes enhanced by decreasing the power-law index but increasing the volume fraction of nanoparticles. Increase of porosity level and buoyancy forces of the medium augments flow strength and results in a thinner boundary layer within the cavity. At negligible porosity level of the enclosure, effect of volume fraction of nanoparticles over thermal conductivity of the nanofluids is imperceptible. Interestingly, when the Darcy–Rayleigh number $$Ra^*\gg 10$$ R a ∗ ≫ 10 , the power-law effect becomes more significant than the volume fraction effect in the augmentation of the convective heat transfer process. The local entropy generation is highly dominated by heat transfer irreversibility within the porous enclosure for all conditions of the flow medium. The particular wavy shape of the cavity strongly influences the heat transfer flow pattern and local entropy generation. Interestingly, contour graphs of local entropy generation and local Bejan number show a rotationally symmetric pattern of order two about the center of the wavy cavity.

Analysis of the Effects of Joule Heating and Viscous Dissipation on Combined Pressure-Driven and Electrokinetic Flows in a Two-Parallel Plate Channel with Unequal Constant Temperatures

2018 ◽  
Vol 233 (4) ◽  
pp. 871-879 ◽  
Author(s):  
Harshad Sanjay Gaikwad ◽  
Pranab Kumar Mondal ◽  
Dipankar Narayan Basu ◽  
Nares Chimres ◽  
Somchai Wongwises
Keyword(s):  
Viscous Dissipation ◽  
Entropy Generation ◽  
Joule Heating ◽  
Generation Rate ◽  
Entropy Generation Rate ◽  
Local Entropy ◽  
Temperature Dependent ◽  
Temperature Dependent Viscosity ◽  
Dependent Viscosity ◽  
Local Entropy Generation

In this article, we perform an entropy generation analysis for the micro channel heat sink applications where the flow of fluid is actuated by combined influences of applied pressure gradient and electric field under electrical double layer phenomenon. The upper and lower walls of the channels are kept at different constant temperatures. The temperature-dependent viscosity of the fluid is considered and hence the momentum equation and energy equations are coupled in this study. Also, a hydrodynamic slip condition is employed on the viscous dissipation. For complete analysis of the entropy generation, we use a perturbation approach with lubrication approximation. In this study, we discuss the results depicting variations in the velocity and temperature distributions and their effect on local entropy generation rate and Bejan number in the system. It can be summarized from this analysis that the enhanced velocity gradients in the flow field due to combined effect of temperature-dependent viscosity and Joule heating and viscous dissipative effects, leads to an enhancement in the local entropy generation rate in the system.

Internal Flow Losses: A Fresh Look at Old Concepts

2011 ◽  
Vol 133 (5) ◽  
Author(s):  
Bastian Schmandt ◽  
Heinz Herwig
Keyword(s):  
Flow Field ◽  
Entropy Generation ◽  
Mechanical Energy ◽  
Internal Flow ◽  
Second Law Of Thermodynamics ◽  
Head Loss ◽  
Local Entropy ◽  
Flow Losses ◽  
Loss Coefficients ◽  
Local Entropy Generation

Losses in a flow field due to single conduit components often are characterized by experimentally determined head loss coefficients K. These coefficients are defined and determined with the pressure as the critical quantity. A thermodynamic definition, given here as an alternative, is closer to the physics of flow losses, however. This definition is based upon the dissipation of mechanical energy as main quantity. With the second law of thermodynamics this dissipation can be linked to the local entropy generation in the flow field. For various conduit components K values are determined and physically interpreted by determining the entropy generation in the component as well as upstream and downstream of it. It turns out that most of the losses occur downstream of the components what carefully has to be taken into account when several components are combined in a flow network.

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