Second law analysis of supercritical CO2 partial cooling Brayton cycle with recompression

2018 ◽  
Vol 11 (44) ◽  
pp. 2149-2156 ◽  
Author(s):  
Moises D. Herrera ◽  
Edgardo Castro ◽  
Jorge Duarte ◽  
Guillermo E. Valencia ◽  
Luis G. Obregon
Keyword(s):  
Supercritical Co2 ◽  
Second Law ◽  
Brayton Cycle ◽  
Second Law Analysis

Second Law Analysis of Gas Power Cycles

1989 ◽  
Author(s):  
D. D. Agrawal ◽  
I. S. Chandrakar
Keyword(s):  
Second Law ◽  
Brayton Cycle ◽  
Work Output ◽  
Power Cycles ◽  
Available Energy ◽  
Exchange Processes ◽  
Second Law Analysis ◽  
The Universe ◽  
Selection Of ◽  
The Ideal

Second Law analysis of Gas Power Cycles, used in practice, is presented. The objective of this analysis was to compute the available energy degradations and entropy creations caused by the departures from the ideal standard such as finite temperature difference in heat exchange processes and fluid friction in different pieces of equipment. Various combinations of Brayton cycle with varying irreversibilities were analysed. It was demonstrated that the decrease of shaft work output from ideal maximum, available energy degraded and the increase in the unavailable energy of the Universe are all equal. This analysis will facilitate the selection of combination of equipment which gives more favourable work output.

scholarly journals Analytical Assessment of (Al2O3–Ag/H2O) Hybrid Nanofluid Influenced by Induced Magnetic Field for Second Law Analysis with Mixed Convection, Viscous Dissipation and Heat Generation

Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 498
Author(s):  
Wasim Ullah Khan ◽  
Muhammad Awais ◽  
Nabeela Parveen ◽  
Aamir Ali ◽  
Saeed Ehsan Awan ◽  
...  
Keyword(s):  
Heat Transfer ◽  
Viscous Dissipation ◽  
Entropy Generation ◽  
Heat Generation ◽  
Transfer Rate ◽  
Second Law ◽  
Hybrid Nanofluid ◽  
Entropy Generation Number ◽  
Generation Number ◽  
Second Law Analysis

The current study is an attempt to analytically characterize the second law analysis and mixed convective rheology of the (Al2O3–Ag/H2O) hybrid nanofluid flow influenced by magnetic induction effects towards a stretching sheet. Viscous dissipation and internal heat generation effects are encountered in the analysis as well. The mathematical model of partial differential equations is fabricated by employing boundary-layer approximation. The transformed system of nonlinear ordinary differential equations is solved using the homotopy analysis method. The entropy generation number is formulated in terms of fluid friction, heat transfer and Joule heating. The effects of dimensionless parameters on flow variables and entropy generation number are examined using graphs and tables. Further, the convergence of HAM solutions is examined in terms of defined physical quantities up to 20th iterations, and confirmed. It is observed that large λ1 upgrades velocity, entropy generation and heat transfer rate, and drops the temperature. High values of δ enlarge velocity and temperature while reducing heat transport and entropy generation number. Viscous dissipation strongly influences an increase in flow and heat transfer rate caused by a no-slip condition on the sheet.

Second Law Analysis of Spray Evaporation

1990 ◽  
Vol 112 (2) ◽  
pp. 130-135 ◽  
Author(s):  
S. K. Som ◽  
A. K. Mitra ◽  
S. P. Sengupta
Keyword(s):  
Heat Transfer ◽  
Reynolds Number ◽  
Entropy Generation ◽  
Exergy Analysis ◽  
Droplet Evaporation ◽  
Second Law ◽  
Hot Gas ◽  
Second Law Analysis ◽  
Initial Drop ◽  
Parallel Stream

A second law analysis has been developed for an evaporative atomized spray in a uniform parallel stream of hot gas. Using a discrete droplet evaporation model, an equation for entropy balance of a drop has been formulated to determine numerically the entropy generation histories of the evaporative spray. For the exergy analysis of the process, the rate of heat transfer and that of associated irreversibilities for complete evaporation of the spray have been calculated. A second law efficiency (ηII), defined as the ratio of the total exergy transferred to the sum of the total exergy transferred and exergy destroyed, is finally evaluated for various values of pertinent input parameters, namely, the initial Reynolds number (Rei = 2ρgVixi/μg) and the ratio of ambient to initial drop temperature (Θ∞′/Θi′).

Second Law Analysis of Solid Desiccant Rotary Dehumidifiers

1988 ◽  
Vol 110 (1) ◽  
pp. 2-9 ◽  
Author(s):  
E. Van den Bulck ◽  
S. A. Klein ◽  
J. W. Mitchell
Keyword(s):  
Local Maximum ◽  
Operating Conditions ◽  
Second Law ◽  
Transfer Coefficients ◽  
Adiabatic Flow ◽  
Transfer Processes ◽  
Air Stream ◽  
Second Law Analysis ◽  
Pass Through ◽  
Air Streams

This paper presents a second law analysis of solid desiccant rotary dehumidifiers. The equations for entropy generation for adiabatic flow of humid air over a solid desiccant are developed. The generation of entropy during operation of a rotary dehumidifier with infinite transfer coefficients is investigated and the various sources of irreversibility are identified and quantified. As they pass through the dehumidifier, both the process and regeneration air streams acquire nonuniform outlet states, and mixing both of these air streams to deliver homogeneous outlet streams is irreversible. Transfer of mass and energy between the regeneration air stream and the desiccant matrix occurs across finite differences in vapor pressure and temperature and these transfer processes generate entropy. The second law efficiency of the dehumidifier is given as a function of operating conditions and the effect of finite transfer coefficients for an actual dehumidifier is discussed. It is shown that operating the rotary dehumidifier at conditions that minimize regeneration energy also yields a local maximum for the second law efficiency.

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