Entropy generation for natural convection in a partitioned cavity, with adiabatic horizontal and isothermally cooled vertical walls, is studied numerically by both a FORTRAN code and the commercially available CFD-ACE software. Effects of the Rayleigh number, the position of the heated partition, and the dimensionless temperature difference on the local and average entropy generation rate are i...

The effect of two heat additions, rather than one, in a gas turbine engine is analyzed from the second law of thermodynamics point of view. A regenerative Brayton cycle model is used for this study, and compared with other models of Brayton cycle. All fluid friction losses in the compressor and turbine are quantified by an isentropic efficiency term. The effect of pressure ratio, turbine inlet ...

A second-law analysis of a gravity-driven film of non-Newtonian fluid along an inclined heated plate is investigated. The flow is assumed to be steady, laminar and fully-developed. The upper surface of the liquid film is considered to be free and adiabatic. The effect of heat generation by viscous dissipation is included. Velocity, temperature and entropy generation profiles are presented. The ...

Department of Mechanical Engineering, National Institute of Technology Silchar Silchar, Assam, India E-mail:[email protected] or [email protected] ABSTRACT A finite-time thermodynamic modelling and simulation of irreversible Diesel cycle engines has been developed considering non-linear variable specific heats with temperature, heat transfer loss, internal irreversibility effects and engin...

This article presents the exact solutions of the velocity and temperature fields for a steady fully developed magnetohydrodynamic flow of a viscous incompressible and electrically conducting fluid between two horizontal concentric cylinders. Our study focuses on the influence of the Hartmann number, Brinkman number, Péclet number and inner radius on the fluid temperature field, entropy generati...

This study analyzes the unsteady Rivlin-Ericksen fluid and irreversibility of exponentially temperature dependent variable viscosity of hydromagnetic two-step exothermic chemical reactive flow along the channel axis with walls convective cooling. The non-Newtonian Hele-Shaw flow of Rivlin-Erickson fluid is driven by bimolecular chemical kinetic and unvarying pressure gradient. The reactive flui...

The unavoidable irreversible loss of power in a heat engine is found to be of quantum origin. Following thermodynamic tradition a model quantum heat engine operating in an Otto cycle is analyzed, where the working medium is composed of an ensemble of harmonic oscillators and changes in volume correspond to changes in the curvature of the potential well. Equations of motion for quantum observabl...

The thermodynamic analysis of irreversible processes has an important influence in energy efficiency growing of any thermodynamic processes or systems. All of thermodynamic processes are entropy generators but there are processes with such a high level of irreversibility so that couldn’t be ignored. That is why is so important to provide a feel for what causes entropy generation and to identify...

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 ...