نتایج جستجو برای: entropy generation

تعداد نتایج: 418190  

2007
H. Al-Qahtani B. S. Yilbas

Laser pulse heating of solid surface and entropy generation during the heating process are considered. Time exponentially decaying pulse is accommodated in the analysis and the laser pulse parameter (b1/b2) resulting in minimum entropy generation rate is computed. Analytical solutions for temperature rise are presented and volumetric entropy generation rate is formulated. Two laser pulses resul...

2014
Ethan Perez

by Ethan Perez Entropy generation in a highly-loaded, axial turbine stage was investigated at on and off-design conditions. Deviation angle, total pressure, total temperature, and specific entropy change were measured experimentally and used as validation for a RANS simulation. A RANS entropy transport model was proposed in order to decompose entropy transport into reversible and irreversible c...

Analysis of intrinsic irreversibility and heat transfer in a buoyancy-driven changeable viscosity liquid along an incline heated wall with convective cooling taking into consideration the heated isothermal and isoflux wall is investigated. By Newton’s law of cooling, we assumed the free surface exchange heat with environment and fluid viscosity is exponentially dependent on temperature. Appropr...

This study numerically investigated heat transfer and fluid flow characteristics in a novel cylindrical heat sink with helical minichannels for the laminar flow of fluid with temperature-dependent properties. A finite volume method was employed to obtain the solution of governing equations. The effects of helical angle, channel aspect ratio, and Reynolds number, which were regarded as main para...

In this paper, an enhanced computational code was developed using finite-volume method for solving the incompressible natural convection flow within the cylindrical cavities. Grids were generated by an easy method with a view to computer program providing. An explicit integration algorithm was applied to find the steady state condition. Also instead of the conventional algorithms of SIMPLE, SIM...

The necessity for decrease in consumption of conventional fuel, related energy and to promote the use of renewable sources such as biofuels, demands for the effective evaluation of the performance of engines based on laws of thermodynamics. Energy, exergy, entropy generation, mean gas temperature and exhaust gas temperature analysis of CI engine using diesel and karanja methyl ester blends at d...

In this study, mixed convection heat transfer and local and global entropy generation in aventilated square cavity have been investigated numerically. The natural convection effect isachieved by a constant heat flux imposed at the bottom wall and cooled by injecting a coldfollow. In order to investigate the effect of port location, four different placementconfigurations of the inlet and outlet ...

Network security is very important when sending confidential data through the network. Cryptography is the science of hiding information, and a combination of cryptography solutions with cognitive science starts a new branch called cognitive cryptography that guarantee the confidentiality and integrity of the data. Brain signals as a biometric indicator can convert to a binary code which can be...

2013
Ali Mchirgui Nejib Hidouri

The paper provides a numerical investigation of the entropy generation analysis due to natural convection in an inclined square porous cavity. The coupled equations of mass, momentum, energy and species conservation are solved using the Control Volume Finite-Element Method. Effect of medium permeability and inclination angle on entropy generation is analysed. It was found that according to the ...

ژورنال: اقتصاد مقداری 2015

An economic system is comprised of different primary flows that can be captured in macroeconomic models with complex network relations. Theoretically and empirically in this system, weak substitution or complementarity of environmental materials, like energy and other production factors such as capital, is undeniable. This is an effective critique on neoclassical economics. In this paper, we vi...

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