scholarly journals Exergy analysis of marine steam turbine labyrinth (gland) seals

Pomorstvo ◽  
2019 ◽  
Vol 33 (1) ◽  
pp. 76-83 ◽  
Author(s):  
Ivan Lorencin ◽  
Nikola Anđelić ◽  
Vedran Mrzljak ◽  
Zlatan Car
Keyword(s):  
Ambient Temperature ◽  
Steam Turbine ◽  
Exergy Analysis ◽  
Numerical Models ◽  
Operating Regime ◽  
Exergy Efficiency ◽  
Specific Enthalpy ◽  
Labyrinth Seals ◽  
Proper Operation ◽  
Operating Regimes

The paper presents an exergy analysis of marine steam turbine labyrinth (gland) seals - an inevitable component of any marine steam turbine cylinder, in three different operating regimes. Throughout labyrinth seals, steam specific enthalpy can be considered as a constant because the results obtained by this assumption do not deviate significantly from the results of complex numerical models. Changes in labyrinth seals exergy efficiency and specific exergy destruction are reverse proportional. The analyzed labyrinth seals have high exergy efficiencies in each observed operating regime at the ambient temperature of 298 K (above 92%), what indicates seals proper operation. An increase in the ambient temperature resulted with a decrease in labyrinth seals exergy efficiency, but even at the highest observed ambient temperature of 318 K, seals exergy efficiency did not fall below 90.5% in each observed operating regime.

scholarly journals The influence of various optimization algorithms on nuclear power plant steam turbine exergy efficiency and destruction

Pomorstvo ◽  
2021 ◽  
Vol 35 (1) ◽  
pp. 69-86
Author(s):  
Vedran Mrzljak ◽  
Nikola Anđelić ◽  
Ivan Lorencin ◽  
Sandi Sandi Baressi Šegota
Keyword(s):  
Power Plant ◽  
Nuclear Power Plant ◽  
Nuclear Power ◽  
Exergy Analysis ◽  
Optimization Algorithms ◽  
Operating Regime ◽  
Simplex Algorithm ◽  
Exergy Efficiency ◽  
Mechanical Power ◽  
Operating Regimes

This paper presents an exergy analysis of the whole turbine, turbine cylinders and cylinder parts in four different operating regimes. Analyzed turbine operates in nuclear power plant while three of four operating regimes are obtained by using optimization algorithms – SA (Simplex Algorithm), GA (Genetic Algorithm) and IGSA (Improved Genetic-Simplex Algorithm). IGSA operating regime gives the highest developed mechanical power of the whole turbine equal to 1022.48 MW, followed by GA (1020.06 MW) and SA (1017.16 MW), while in Original operating regime whole turbine develop mechanical power equal to 996.29 MW. In addition, IGSA causes the highest increase in developed mechanical power of almost all cylinders and cylinder parts in comparison to the Original operating regime. All observed optimization algorithms increases the exergy destruction of the whole turbine in comparison to Original operating regime - the lowest increase causes IGSA, followed by GA and finally SA. The highest exergy efficiency of the whole turbine, equal to 85.92% is obtained by IGSA, followed by GA (85.89%) and SA (85.82%), while the lowest exergy efficiency is obtained in Original operating regime (85.70%). Analyzed turbine, which operates by using wet steam is low influenced by the ambient temperature change. IGSA, which shows dominant performance in exergy analysis parameters of the analyzed turbine, in certain situations is overpowered by GA. Therefore, in optimization of steam turbine performance, IGSA and GA can be recommended.

scholarly journals Exergy Analysis of 1 x 135 MW Jeneponto Steam Power Plant

2021 ◽  
Vol 7 (2) ◽  
pp. 150
Author(s):  
Nur Hamzah ◽  
A.M Shiddiq Yunus ◽  
Waqva Enno Al Fadiyah
Keyword(s):  
Power Plant ◽  
Ambient Temperature ◽  
Exergy Analysis ◽  
Exergy Efficiency ◽  
Second Law ◽  
Exergy Destruction ◽  
Steam Power ◽  
Total Destruction ◽  
Destruction Efficiency ◽  
Mass Flowrate

Exergy analysis is application of the second law thermodynamics which provides information about large exergy, exergy efficiency, destruction, and destruction efficiency in each component of PLTU so can be reference for improvement and optimization in an effort to reduce losses and increase efficiency. The exergy value obtained from calculating mass flowrate, enthalpy, ambient temperature, and entropy. The destruction value is obtained from difference between input exergy value and exergy output. The destruction exergy value from comparison between output exergy value to input exergy value, and destruction efficiency value from comparison of destruction value to total destruction value of PLTU components. The results showed that the largest exergy occurred in boilers, namely 778.225 MW in 2018, 788.824 MW in 2019, and 796.824 MW in 2020, lowest exergy value in CP was 0.160 MW in 2018, 0.176 MW in 2019, and 0.160 MW in 2020. The largest destruction occurred in boilers, namely 163.970 MW with destruction efficiency 79.242% in 2018, 179.450 MW with destruction efficiency 82.111% in 2019, and 199.637 MW with destruction efficiency 83.448% in 2020, lowest exergy destruction value at CP, namely 0.056 MW with destruction efficiency 0.027% in 2018, 0.059 MW with destruction efficiency 0.027% in 2019, and 0.056 MW with destruction efficiency 0.023% in 2020. The exergy efficiency occurred in HPH 2, amounting to 94.750% in 2018, 95.187 % in 2019, and 94.728% in 2020, while lowest of exergy efficiency was in LPH 1, namely 43.637 MW in 2018, 33.512 MW in 2019, and 38.764 MW in 2020.

Thermodynamic modeling and Exergy Analysis of Gas Turbine Cycle for Different Boundary conditions

2015 ◽  
Vol 6 (2) ◽  
pp. 205 ◽  
Author(s):  
Lalatendu Pattanayak
Keyword(s):  
Ambient Temperature ◽  
Combustion Chamber ◽  
Gas Turbine ◽  
Exergy Analysis ◽  
Load Condition ◽  
Exergy Efficiency ◽  
Inlet Temperature ◽  
Exergy Destruction ◽  
And Performance ◽  
Topping Cycle

In this study an exergy analysis of 88.71 MW 13D2 gas turbine (GT) topping cycle is carried out. Exergy analysis based on second law was applied to the gas cycle and individual components through a modeling approach. The analysis shows that the highest exergy destruction occurs in the combustion chamber (CC). In addition, the effects of the gas turbine load and performance variations with ambient temperature, compression ratio and turbine inlet temperature (TIT) are investigated to analyse the change in system behavior. The analysis shows that the gas turbine is significantly affected by the ambient temperature which leads to a decrease in power output. The results of the load variation of the gas turbine show that a reduction in gas turbine load results in a decrease in the exergy efficiency of the cycle as well as all the components. The compressor has the largest exergy efficiency of 92.84% compared to the other component of the GT and combustion chamber is the highest source of exergy destruction of 109.89 MW at 100 % load condition. With increase in ambient temperature both exergy destruction rate and exergy efficiency decreases.

scholarly journals Modelling of energy and exergy analysis of ORC integrated systems in terms of sustainability by applying artificial neural network

2020 ◽  
Author(s):  
Zafer Utlu ◽  
Mert Tolon ◽  
Arif Karabuga
Keyword(s):  
Neural Network ◽  
Artificial Neural Network ◽  
Solar Energy ◽  
Ambient Temperature ◽  
Exergy Analysis ◽  
Energy System ◽  
Exergy Efficiency ◽  
Energy And Exergy ◽  
Energy And Exergy Analysis ◽  
Artificial Neural

Abstract The present study focuses on the organic Rankine cycle (ORC) integrated into an evacuated tube heat pipe (ETHP), whose systems are an alternative solar energy system to low-efficiency planary collectors. In this work, a detailed thermodynamic and artificial neural network (ANN) analysis was conducted to evaluate the solar energy system. One of the key parameters of sustainable approaches focused on exergy efficiency is application of thermal engineering. In addition to this, sustainable engineering approaches nowadays are a necessity for improving the efficiency of all of the engineering research areas. For this reason, the ANN model is used to forecast different types of energy efficiency problems in thermodynamic literature. The examined system consists of two main parts such as the ETHP system and the ORC system used for thermal energy production. With this system, it is aimed to evaluate energy and exergy analysis results by the ANN method in the case of integrating the ORC system to ETHP, which is one of the planar collectors suitable for the roofs of the buildings. Within the scope of this study, the exergy efficiency was evaluated on the developed ANN algorithm. The effect rates of parameters such as pressure, temperature and ambient temperature affecting the exergy efficiency of ORC integrated ETHP were calculated. Ambient temperature was found to be the most influential parameter on exergy efficiency. The exergy efficiency of the whole system has been calculated as ~23.39%. The most suitable BPNN architecture for this case study is recurrent networks with dampened feedback (Jordan–Elman nets). The success rate of the developed BPNN model is 95.4%.

scholarly journals Analysis of Operation Parameters of Fish Refrigeration by Exergy Analysis. Case Study

2019 ◽  
Vol 23 (1) ◽  
pp. 229-241
Author(s):  
Edvins Terehovics ◽  
Ivars Veidenbergs ◽  
Dagnija Blumberga
Keyword(s):  
Energy Efficiency ◽  
Ambient Temperature ◽  
Working Conditions ◽  
Temperature Difference ◽  
Exergy Analysis ◽  
Exergy Efficiency ◽  
Single Stage ◽  
Exergy Destruction ◽  
Refrigeration System ◽  
The Ideal

Abstract Unlike energy efficiency, in terms of exergy efficiency it is possible to compare the existing operation of an energy conversion system with the ideal operation. Exergy loses and exergy destruction make it possible to identify the shortcomings of an existing system, which should be improved immediately. With exergy analysis, it is possible to identify the priority actions that need to be taken in order to improve the functioning of the system: greater exergy loss prevention is the highest priority. Energy efficiency refers to the useful work and investments needed to obtain useful work and investments needed to obtain energy efficiency; this is important to some extent, but the effectiveness of exergy makes it possible to compare system performance with the ideal. Results shows that the highest exergy destruction of a single-stage compressor refrigeration system from all working condition is found when ambient temperature and freezer temperature difference is 10 ºC, pressure in compressor is 0.62 MPa, ammonia temperature after compressor is 90 ºC, total exergy destruction of single-stage compressor refrigeration system 97.84 kW. The highest exergy efficiency of a single-stage compressor refrigeration system from all the working conditions is found when ambient temperature and freezer temperature difference is 39 ºC, pressure in compressor is 0.45 MPa, ammonia temperature after compressor is 128 ºC, exergy efficiency of a single-stage compressor refrigeration system is 59.76 %. The highest total exergy destruction of a two-stage compressor refrigeration system from among all the working conditions is found to be when the ambient temperature and freezer temperature difference is at 13 ºC, pressure in compressor 0.44 MPa, ammonia temperature after compressor 76 ºC, total exergy destruction 83.86 kW. The highest exergy efficiency of a two-stage compressor refrigeration system from among all the working conditions is found to be at an ambient temperature and freezer temperature difference of 39 ºC, pressure in compressor 0.56 MPa, ammonia temperature after compressor 92 ºC, exergy efficiency 53.55 %.

Exergy Analysis of Thermal Energy Storage With Specific Remarks on the Variation of the Environmental Temperature

1996 ◽  
Vol 118 (2) ◽  
pp. 81-88 ◽  
Author(s):  
G. Bisio
Keyword(s):  
Energy Storage ◽  
Constant Temperature ◽  
Exergy Analysis ◽  
Environmental Temperature ◽  
Variable Temperature ◽  
Thermal Storage ◽  
Exergy Efficiency ◽  
Basic Question ◽  
Storage Devices ◽  
Temperature Environment

Energy storage is a key technology for many purposes and in particular for air conditioning plants and a successful exploitation of solar energy. Thermal storage devices are usually classified as either variable temperature (“sensible heat”) or constant temperature (“latent heat”) devices. For both models a basic question is to determine the efficiency suitably: Only exergy efficiency appears a proper way. The aim of this paper is to examine exergy efficiency in both variable and constant temperature systems. From a general statement of exergy efficiency by the present author, two types of actual definitions are proposed, depending on the fact that the exergy of the fluid leaving the thermal storage during the charge phase can be either totally lost or utilized elsewhere. In addition, specific remarks are made about the exergy of a system in a periodically varying temperature environment.

Steady State Detection in Industrial Gas Turbines for Condition Monitoring and Diagnostics Applications

2014 ◽  
Author(s):  
Cesar Celis ◽  
Érica Xavier ◽  
Tairo Teixeira ◽  
Gustavo R. S. Pinto
Keyword(s):  
Steady State ◽  
Condition Monitoring ◽  
Gas Turbines ◽  
Signal Analysis ◽  
Operating Regime ◽  
State Detection ◽  
Industrial Gas Turbines ◽  
Monitoring And Diagnostics ◽  
Operating Regimes

This work describes the development and implementation of a signal analysis module which allows the reliable detection of operating regimes in industrial gas turbines. Its use is intended for steady state-based condition monitoring and diagnostics systems. This type of systems requires the determination of the operating regime of the equipment, in this particular case, of the industrial gas turbine. After a brief introduction the context in which the signal analysis module is developed is highlighted. Next the state of the art of the different methodologies used for steady state detection in equipment is summarized. A detailed description of the signal analysis module developed, including its different sub systems and the main hypotheses considered during its development, is shown to follow. Finally the main results obtained through the use of the module developed are presented and discussed. The results obtained emphasize the adequacy of this type of procedures for the determination of operating regimes in industrial gas turbines.

A Comparative Evaluation of Advanced Combined Cycle Alternatives

1991 ◽  
Vol 113 (2) ◽  
pp. 190-197 ◽  
Author(s):  
O. Bolland
Keyword(s):  
Heat Transfer ◽  
Steam Turbine ◽  
Comparative Evaluation ◽  
Exergy Analysis ◽  
Combined Cycle ◽  
Heat Transfer Area ◽  
Turbine Condenser ◽  
Pressure Cycle ◽  
Steam Turbine Condenser ◽  
Exergy Balance

This paper presents a comparison of measures to improve the efficiency of combined gas and steam turbine cycles. A typical modern dual pressure combined cycle has been chosen as a reference. Several alternative arrangements to improve the efficiency are considered. These comprise the dual pressure reheat cycle, the triple pressure cycle, the triple pressure reheat cycle, the dual pressure supercritical reheat cycle, and the triple pressure supercritical reheat cycle. The effect of supplementary firing is also considered for some cases. The different alternatives are compared with respect to efficiency, required heat transfer area, and stack temperature. A full exergy analysis is given to explain the performance differences for the cycle alternatives. The exergy balance shows a detailed breakdown of all system losses for the HRSG, steam turbine, condenser, and piping.

Exergy Analysis of a Combined Power and Refrigeration Thermodynamic Cycle Driven by a Solar Heat Source

2003 ◽  
Vol 125 (1) ◽  
pp. 55-60 ◽  
Author(s):  
Afif Akel Hasan ◽  
D. Y. Goswami
Keyword(s):  
Heat Source ◽  
Exergy Analysis ◽  
Thermodynamic Cycle ◽  
Exergy Efficiency ◽  
Operating Conditions ◽  
Optimum Operating ◽  
Water Mixture ◽  
Exergy Destruction ◽  
Ammonia Water ◽  
Solar Heat

Exergy thermodynamics is employed to analyze a binary ammonia water mixture thermodynamic cycle that produces both power and refrigeration. The analysis includes exergy destruction for each component in the cycle as well as the first law and exergy efficiencies of the cycle. The optimum operating conditions are established by maximizing the cycle exergy efficiency for the case of a solar heat source. Performance of the cycle over a range of heat source temperatures of 320–460°K was investigated. It is found that increasing the heat source temperature does not necessarily produce higher exergy efficiency, as is the case for first law efficiency. The largest exergy destruction occurs in the absorber, while little exergy destruction takes place in the boiler.

An Investigation of Tip Force Characteristics of Brush Seals

2007 ◽  
Author(s):  
Mehmet Demiroglu ◽  
Mustafa Gursoy ◽  
John A. Tichy
Keyword(s):  
Cantilever Beam ◽  
Numerical Models ◽  
Operating Conditions ◽  
Beam Equation ◽  
Labyrinth Seals ◽  
Wide Range ◽  
Brush Seals ◽  
Cantilever Beam Equation ◽  
Super Alloy ◽  
Force Pressure

Thanks to their compliant nature and superior leakage performance over conventional labyrinth seals, brush seals found increasing use in turbomachinery. Utilizing high temperature super-alloy fibers and their compliance capability these seals maintain contact with the rotor for a wide range of operating conditions leaving minimal passage for parasitic leakage flow. Consequently, the contact force/pressure generated at seal rotor interface is of importance for sustained seal performance and longevity of its service life. Although some analytical and numerical models have been developed to estimate bristle tip pressures, they simply rely on linear beam equation calculations and other such assumptions for loading cases. In this paper, previously available analytical and/or numerical models for bristle tip force/pressure have been modified and enhanced. The nonlinear cantilever beam equation has been solved and results are compared to a linear cantilever beam equation solution to establish application boundaries for both methods. The results are also compared to experimental data. With the support of testing, an empirical model has been developed for tip forces under operating conditions.

Sign in / Sign up

Export Citation Format

Share Document