97/04040 First and Second Law analysis of diesel engines and gas turbines in combined cycles: a comparative study

1997 ◽  
Vol 38 (5) ◽  
pp. 340
Keyword(s):  
Comparative Study ◽  
Diesel Engines ◽  
Gas Turbines ◽  
Second Law ◽  
Second Law Analysis ◽  
Combined Cycles

Performance Evaluation of Selected Combustion Gas Turbine Cogeneration Systems Based on First and Second-Law Analysis

1990 ◽  
Vol 112 (1) ◽  
pp. 117-121 ◽  
Author(s):  
F. F. Huang
Keyword(s):  
Performance Evaluation ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Decision Makers ◽  
Utilization Efficiency ◽  
Second Law ◽  
Pinch Point ◽  
Combustion Gas ◽  
Second Law Analysis ◽  
Industrial Gas Turbines

The thermodynamic performance of selected combustion gas turbine cogeneration systems has been studied based on first-law as well as second-law analysis. The effects of the pinch point used in the design of the heat recovery steam generator, and pressure of process steam on fuel-utilization efficiency (first-law efficiency), power-to-heat ratio, and second-law efficiency, are examined. Results for three systems using state-of-the-art industrial gas turbines show clearly that performance evaluation based on first-law efficiency alone is inadequate. Decision makers should find the methodology contained in this paper useful in the comparison and selection of cogeneration systems.

scholarly journals Second-Law Analysis of Irreversible Losses in Gas Turbines

Entropy ◽  
2017 ◽  
Vol 19 (9) ◽  
pp. 470 ◽  
Author(s):  
Yan Jin ◽  
Juan Du ◽  
Zhiyuan Li ◽  
Hongwu Zhang
Keyword(s):  
Gas Turbines ◽  
Second Law ◽  
Second Law Analysis

SCRC Technology for Naval Propulsion

2014 ◽  
Author(s):  
Hans E. Wettstein
Keyword(s):  
Gas Turbine ◽  
Diesel Engines ◽  
Thermal Efficiency ◽  
Gas Turbines ◽  
Liquid Fuel ◽  
Good Evidence ◽  
Liquid Fuels ◽  
Specific Mass ◽  
Combined Cycles ◽  
Operation Control

Supercharged Diesel engines are nowadays dominating naval propulsion. They have a thermal efficiency up to 50% and can swallow almost any liquid fuel. But there are two main drawbacks: Nitrogen oxides emissions of Diesel engines are sometimes higher than desired. Low speed vibrations can often be felt everywhere on the vessel. Some cruising ships therefore use gas turbines in spite of the lower thermal efficiency. But instead of supercharging Diesel engines also gas turbines can be supercharged. In combination with recuperation they could achieve even a higher thermal efficiency than Diesel engines. Such a concept with the name “Semi-Closed Recuperated Cycle” (SCRC) has been proposed in [1] for replacing gas turbine combined cycles. This paper shows new results of thermodynamic calculations of the SCRC with adiabatic or intercooled compressors. These calculations are optimized for naval applications with liquid fuels. The state of the SCRC technology is described with its expected operation, control concepts and limitations. Based on this investigation there is good evidence that supercharged Diesel technology for naval application could be seriously competed by the SCRC technology with respect to thermal efficiency, vibration (engine smoothness), emissions and specific mass (per kW power). It is the declared intention of the author to find companies who are interested in developing this technology.

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′).

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