Thermodynamic cycle simulation of the diesel cycle: Exergy as a second law analysis parameter

1989 ◽  
Vol 16 (3) ◽  
pp. 335-346 ◽  
Author(s):  
S.V. Kumar ◽  
W.J. Minkowycz ◽  
K.S. Patel
Solar Energy ◽  
2002 ◽  
Vol 73 (5) ◽  
pp. 385-393 ◽  
Author(s):  
Afif Akel Hasan ◽  
D.Yogi Goswami ◽  
Sanjay Vijayaraghavan

Author(s):  
J B Woodward

It is asserted that some of the mechanical engineering literature on power cycle analysis does not make sufficient use of the second law of thermodynamics. Advantages of second-law use are listed and then demonstrated through development by equations by which analysis of an air-standard diesel cycle can incorporate constant-pressure turbocharging and a Rankine bottoming cycle. Steps towards application to real machinery are also demonstrated. Four numerical examples are included.


Author(s):  
Jerald A. Caton

The use of exhaust gas recirculation (EGR) for a spark-ignition engine was examined using a thermodynamic cycle simulation including the second law of thermodynamics. Both a cooled and an adiabatic EGR configuration were considered. The engine was a 5.7 liter, automotive engine operating from idle to wide open throttle, and up to 6000 rpm. First, the reduction of nitric oxides is quantified for the base case condition (bmep = 325 kPa, 1400 rpm, φ = 1.0 and MBT timing). Over 90% reduction of nitric oxides is obtained with about 18% EGR for the cooled configuration, and with about 26% EGR for the adiabatic configuration. For constant load and speed, the thermal efficiencies increase with increasing EGR for both configurations, and the results show that this increase is mainly due to decreasing pumping losses and decreasing heat losses. In addition, results from the second law of thermodynamics indicated an increase in the destruction of availability (exergy) during the combustion process as EGR levels increase for both configurations. The major reason for this increase in the destruction of availability was the decrease in the combustion temperatures. Complete results for the availability destruction are provided for both configurations.


Coatings ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 498
Author(s):  
Wasim Ullah Khan ◽  
Muhammad Awais ◽  
Nabeela Parveen ◽  
Aamir Ali ◽  
Saeed Ehsan Awan ◽  
...  

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.


1990 ◽  
Vol 112 (2) ◽  
pp. 130-135 ◽  
Author(s):  
S. K. Som ◽  
A. K. Mitra ◽  
S. P. Sengupta

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′).


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