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Wyświetlanie 1-15 z 366
Tytuł:
3D multistage computations of turbine flows using different state equations
Autorzy:
Rusanov, A. V.
Yershov, S.
Lampart, P.
Świrdyczuk, J.
Gardzielewicz, A.
Powiązania:
https://bibliotekanauki.pl/articles/1931597.pdf
Data publikacji:
2002
Wydawca:
Politechnika Gdańska
Tematy:
3D RANS model
state equation
low pressure steam turbine
Opis:
The paper describes the implementation of a modified state equation for perfect gas and Tammann equation into a 3D RANS solver FlowER. In the modification the specific heats are assumed as linear functions of temperature. A 5-stage LP steam turbine stage is calculated, and the comparison of results for constant and variable specific heats is illustrated. The modification significantly improves the correctness of determination of thermodynamic parameters in the entire flow region, especially in the exit stage.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2002, 6, 4; 591-600
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
6-stroke engine: thermodynamic modelling and design for testing
Autorzy:
Nimsiriwangso, Atip
Barnes, Paul
Doustdar, Omid
Wyszynski, Miroslaw L.
Mohyeldin, Gasim Mohamed Maisara
Kowalski, Miroslaw
Powiązania:
https://bibliotekanauki.pl/articles/241771.pdf
Data publikacji:
2019
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
six-stroke engine
water injection
steam expansion
engine efficiency
dynamic gas model
Opis:
In the study AVL BOOST™ is used to perform a thermodynamic simulation of a six-stroke engine, being built by a research team based in Saudi Arabia. The six-stroke cycle consists of a standard four-stroke Otto Cycle followed by a heat recovering steam expansion cycle. Water is injected into the hot combustion chamber towards the end of the Otto expansion stroke producing steam, which is used to perform work on a piston. This process produces power using waste heat and therefore increases the overall efficiency of the engine. The Robin EY28D engine, which is a single cylinder, four-stroke, gasoline engine was used for this simulation study. The engine was modelled and converted into six-stroke engine in AVL BOOST. The results show that six-stroke engine is more efficient than four-stroke engine. In six-stroke engine, the engine power is increased by 33.1% and brake specific fuel consumption (BSFC) is decreased by approximately 16%. Where emissions are concerned, Nitrogen Oxide (NOx) emission from six-stroke engine is reduced by 80%, while the Hydrocarbon (HC) emission increases by 85% compared with the original 4-stroke. Moreover, the most efficient camshaft was found and designed according to the most efficient valve profile for this engine, which is combination of 60CA° of valve duration and 10 mm of valve lifting.
Źródło:
Journal of KONES; 2019, 26, 2; 93-106
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A fuzzy controller with a real-time tuning algorithm and its application to a steam generator water level control
Autorzy:
Jung, C.
Kwon, K.
Powiązania:
https://bibliotekanauki.pl/articles/205893.pdf
Data publikacji:
1998
Wydawca:
Polska Akademia Nauk. Instytut Badań Systemowych PAN
Tematy:
sterowanie rozmyte
sterownik z logikami rozmytymi
fuzzy controller
instantaneous system performance
scaling factor
self-tuning
steam generator
Opis:
It is nesessary to tune the fuzzy rules and the scalling factors in real-time control of a large scale system, the steam generator of a nuclear power plant, as it is related to safety and availability of the plant. A novel real-time tuning algorithm of fuzzy controller based on the scaling factors is proposed and applied to the steam generator water level control system of the nuclear power plant. The new real-time tuning algorithm adopts a variable reference tuning index for a good system tuning response and an instantaneous system fuzzy performance for scaling factor tuning. For the fuzzy steam generator controller, an image signal of feedwater flow error at low power is proposed and pressure compensation rules and a gain scheduler of feedwater temperature are designed also. The fuzzy controller of the steam generator water level is simulated by the proposed method. The simulation results show that the improved performance of the steam generator water level controller by the proposed method.
Źródło:
Control and Cybernetics; 1998, 27, 4; 545-564
0324-8569
Pojawia się w:
Control and Cybernetics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A mathematical model of two-stage Solid Oxide Fuel Cell, SOFC, stacks for dynamic simulation of Combined Heat and Power system fed by natural gas
Autorzy:
Palus, Mateusz
Pianko-Oprych, Paulina
Powiązania:
https://bibliotekanauki.pl/articles/1849273.pdf
Data publikacji:
2021
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
dynamic model
natural gas
Solid Oxide Fuel Cell stacks
Combined Heat and Power
CHP
system
Balance of Plant
BoP
modelling
Catalytic Partial Oxidation
CPOx
reformer
steam reformer
Opis:
Zero-dimensional two-stage SOFC stacks dynamic model was developed to investigate the effect of operating parameters on stacks performance. The model resolves spatially thermal and thermo-electrochemical behaviour for electrochemical reactions, Catalytic Partial Oxidation and Steam Reforming processes. Design variables and thermo-electrochemical properties were obtained from in-house-fabricated SOFCs carried out by project partners. The completed SOFCs based Combined Heat and Power, CHP, system model was validated by data18 and numerical results obtained at steady-state mode showing its high-fidelity. A parametric study with respect to key operating parameters including changes in fuel utilization, lambda number and current density values was conducted. The global CHP system dynamic response, in term of the current/voltage delivered by two-stage SOFC stacks, under a fi xed fuel utilization, has been determined resulting in greater variations in the voltage of a single cell in the first stack in comparison to the corresponding values in the second stack.
Źródło:
Polish Journal of Chemical Technology; 2021, 23, 2; 1-11
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A mathematical model of two-stage Solid Oxide Fuel Cell, SOFC, stacks for dynamic simulation of Combined Heat and Power system fed by natural gas
Autorzy:
Palus, Mateusz
Pianko-Oprych, Paulina
Powiązania:
https://bibliotekanauki.pl/articles/1849268.pdf
Data publikacji:
2021
Wydawca:
Zachodniopomorski Uniwersytet Technologiczny w Szczecinie. Wydawnictwo Uczelniane ZUT w Szczecinie
Tematy:
dynamic model
natural gas
Solid Oxide Fuel Cell stacks
Combined Heat and Power
CHP
system
Balance of Plant
BoP
modelling
Catalytic Partial Oxidation
CPOx
reformer
steam reformer
Opis:
Zero-dimensional two-stage SOFC stacks dynamic model was developed to investigate the effect of operating parameters on stacks performance. The model resolves spatially thermal and thermo-electrochemical behaviour for electrochemical reactions, Catalytic Partial Oxidation and Steam Reforming processes. Design variables and thermo-electrochemical properties were obtained from in-house-fabricated SOFCs carried out by project partners. The completed SOFCs based Combined Heat and Power, CHP, system model was validated by data18 and numerical results obtained at steady-state mode showing its high-fidelity. A parametric study with respect to key operating parameters including changes in fuel utilization, lambda number and current density values was conducted. The global CHP system dynamic response, in term of the current/voltage delivered by two-stage SOFC stacks, under a fi xed fuel utilization, has been determined resulting in greater variations in the voltage of a single cell in the first stack in comparison to the corresponding values in the second stack.
Źródło:
Polish Journal of Chemical Technology; 2021, 23, 2; 1-11
1509-8117
1899-4741
Pojawia się w:
Polish Journal of Chemical Technology
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method for determining the usability potential of ship steam boilers
Autorzy:
Muślewski, Ł.
Pająk, M.
Landowski, B.
Żółtowski, B.
Powiązania:
https://bibliotekanauki.pl/articles/259611.pdf
Data publikacji:
2016
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
ship steam boilers
operation management
complex technical systems
usability potential
Opis:
Ship large-power steam boiler may serve as an example of complex critical technical system. A basis for rational control of operation of such system is knowledge on its capability of fulfilling the tasks to which it was intended. In order to make it possible to apply computer aiding to operational decision-making the capability should be described analytically. In this paper it was proposed to express the capability of ship steam boiler ( considered a complex system) to perform service tasks, by calculating components of its usability potential in a given instant t. To this end , was distinguished a set of steam boiler fundamental features which formulate space of its technical states. Values and characteristic intervals of the features were defined and this way sub-spaces of serviceability and non-serviceability states of the object in question were determined. Next, in the considered space, technical state of the boiler and its usability potential was determined. Owing to this it become possible to quantitatively express the steam boiler functioning capability which served as a basis for elaborating an algorithm for controlling the operational processes of a complex technical system under action. In this paper is also described a way of application of the presented method to calculation of ship steam boiler usability potential, which may be especially instrumental in the case of operational control of the boilers of the kind , equipped with interstage reheaters, i.e. those operating with high values of operational parameters.
Źródło:
Polish Maritime Research; 2016, 4; 105-111
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A method of diagnosing labyrinth seals in fluid-flow machines
Autorzy:
Krzyślak, P.
Winowiecki, M.
Powiązania:
https://bibliotekanauki.pl/articles/259824.pdf
Data publikacji:
2008
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
labyrinth sealings
steam turbines
sealing diagnostics
Opis:
Steam turbines constitute fluid flow machines which are used for driving engines of power plants, merchant and naval ships. They are commonly applied in power industry to driving electric generators. One of the impotant elements which affect efficiency of steam turbines used in power industry and for ship propulsion is state of labyrinth sealings whose aim is to minimize losses associated with steam leakage within turbine casing. Until now to assess state of labyrinth sealings has been only possible after stopping the turbine and its dismantling in order to determine values of clearances in the sealings. This paper presents a method which makes it possible to assess state of labyrinth sealings without the necessity of stopping and dismantling the machine. This is the method which allows to assess on-line state of machine sealings during its operation.
Źródło:
Polish Maritime Research; 2008, 3; 38-41
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A methodology for online rotor stress monitoring using equivalent Green’s function and steam temperature model
Autorzy:
Banaszkiewicz, M.
Dominiczak, K.
Powiązania:
https://bibliotekanauki.pl/articles/175458.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Steam turbine
thermal stress
Green's functions
Duhamel’s integral
Opis:
The requirement of high operational flexibility of utility power plants creates a need of using online systems for monitoring and control of damage of critical components, e.g., steam turbine rotors. Such systems make use of different measurements and mathematical models enabling calculation of thermal stresses and their continuous control. The paper presents key elements of the proposed system and discusses their use from the point of view of thermodynamics and heat transfer. Thermodynamic relationships, well proven in design calculations, were applied to calculate online the steam temperature at critical locations using standard turbine measurements as input signals. The model predictions were compared with operational data from a real power plant during a warm start-up and show reasonably good accuracy. The effect of variable heat transfer coefficient and material properties on thermal stresses was investigated numerically by finite element method (FEM) on a cylinder model, and a concept of equivalent Green’s function was introduced to account for this variability in thermal stress model based on Duhamel’s integral. This approach was shown to produce accurate results for more complicated geometries by comparing thermal stresses at rotor blade groove computed using FEM and Duhamel’s integral.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2016, 133; 13-37
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new method for determining allowable medium temperature during transient operation of thick-walled elements in a supercritical power plant
Autorzy:
Duda, P.
Rząsa, D.
Powiązania:
https://bibliotekanauki.pl/articles/240343.pdf
Data publikacji:
2010
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
kocioł parowy
naprężenia całkowite
optymalizacja
wymiana ciepła
heat transfer
optimization
steam boilers
total stresses
Opis:
Construction elements of supercritical power plants are subjected to high working pressures and high temperatures while operating. Under these conditions high stresses in the construction are created. In order to operate safely, it is important to monitor stresses, especially during start-up and shut-down processes. The maximum stresses in the construction elements should not exceed the allowable stress limit. The goal is to find optimum operating parameters that can assure safe heating and cooling processes [1-5]. The optimum parameters should guarantee that the allowable stresses are not exceeded and the entire process is conducted in the shortest time. In this work new numerical method for determining optimum working parameters is presented. Based on these parameters heating operations were conducted. Stresses were monitored during the entire processes. The results obtained were compared with the German boiler regulations - Technische Regeln fur Dampfkessel 301.
Źródło:
Archives of Thermodynamics; 2010, 31, 3; 55-72
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A new method for optimum heating of pressure components in supercritical steam power blocks
Autorzy:
Rząsa, D.
Duda, P.
Powiązania:
https://bibliotekanauki.pl/articles/240145.pdf
Data publikacji:
2012
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
kotły parowe
metody optymalizacji
wymiana ciepła
heat transfer
optimization methods
steam boilers
total stresses
Opis:
One of the major concerns of the power energy industries is a proper operation of steam power blocks. Pressurized working medium and high temperature cause very high stresses in the construction elements such as collectors, separators or steam valves. They are exposed to sudden temperature and pressure changes that cause high stresses at certain points. Additionally, the cyclic character of loading causes material fatigue, known as low-cyclic fatigue, which may lead to the formation of fracture. Thus, methodologies offered by many companies should ensure reliable and safe operation of steam power blocks. The advanced numerical solutions for determining time-optimum medium temperature changes are presented. They are based on Levenberg-Marquardt and nonlinear programming by quadratic Lagrangian methods. The methods allow us to find parameters for start-up and shut-down operation that can reduce total stresses to limits governed by European regulations. Furthermore, the heating and cooling operations are conducted in a shortest time possible.
Źródło:
Archives of Thermodynamics; 2012, 33, 3; 133-145
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A simplified mathematical model of a U-tube steam generator under variable load conditions
Autorzy:
Laskowski, R.
Lewandowski, J.
Powiązania:
https://bibliotekanauki.pl/articles/240139.pdf
Data publikacji:
2013
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steam generator
mathematical model under variable load conditions
wytwornica pary
model matematyczny
zmienne warunki obciążenia
Opis:
A steam generator in a nuclear power plant with a light water reactor is a heat exchanger, in which the heat is being transferred from the primary to the secondary loop (it links the primary and secondary loops). When the power plant is running, the inlet parameters (temperatures and mass flow rates) on both sides of the steam generator can change. It is important to know how the changes of these parameters affect the steam generator performance. The complexity of the processes taking place in the steam generator makes it difficult to create a simulator reflecting its performance under changed conditions. In order to simplify the task, the steam generator was considered as a ‘black box’ with the aim of examining how the changes of the inlet parameters affect the changes of the outlet ones. On the basis of the system (steam generator) response, a simple mathematical model of the steam generator under variable load conditions was proposed. In the proposed model, there are two dimensionless parameters and three constant coefficients. A linear relation between these dimensionless parameters was obtained. The correctness of the model was verified against the data obtained with a steam generator simulator for European Pressured Reactor and AP-600 reactors. A good agreement between the proposed model and the simulator data was achieved.
Źródło:
Archives of Thermodynamics; 2013, 34, 3; 75-88
1231-0956
2083-6023
Pojawia się w:
Archives of Thermodynamics
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
A verification approach to thermoelastic steam turbine rotor analysis during transient operation
Autorzy:
Dominiczak, K.
Banaszkiewicz, M.
Powiązania:
https://bibliotekanauki.pl/articles/175490.pdf
Data publikacji:
2016
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steam turbine
thermal stress
thermal growth
differential expansion
Opis:
This paper presents a verification approach to thermoelastic steam turbine rotor analysis. Neither temperature nor stresses are measured on the rotor surface in utility power plants. Therefore analysis of the steam turbine rotor can be verified only based on absolute and differential thermal expansion measurements in vicinity of the steam turbine. Absolute and differential expansion measurements and steam turbine fixed points arrangement allow to calculate thermal growth of the steam turbine rotor during transients. Thermal growth of the rotor can be a baseline for the calculation using a numerical model.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2016, 131; 55-65
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Absolute and relative vibration inconsistencies in dynamic analysis of high power turbogenerator rotating system
Autorzy:
Barzdaitis, V.
Jonušas, R.
Didžiokas, R.
Barzdaitis, V. V.
Powiązania:
https://bibliotekanauki.pl/articles/328904.pdf
Data publikacji:
2004
Wydawca:
Polska Akademia Nauk. Polskie Towarzystwo Diagnostyki Technicznej PAN
Tematy:
turbiny parowe
generator prądu elektrycznego
łożyska ślizgowe
steam turbines
electric generator
journal bearings
absolute and relative vibration
Opis:
The paper presents the research results of machine condition monitoring and fault diagnostics of the High Power Steam Turbines and Electric Generator rotating system. The inconsistencies of journal bearings absolute vibration parameters of the rotating system and journal bearings shafts relative vibration parameters have been shown. In the low frequency range the shafts relative vi-bration displacements are decisive informative in defects diagnostics. The journal bearings sup-ports absolute vibration velocities of low frequencies are being strongly damped by massive bear-ings supports, etc. Journal bearings absolute vibration parameters supply the information errone-ously attributed to the rotor. High frequency absolute vibration acceleration, however, make it possible to provide monitoring of coupling.
Źródło:
Diagnostyka; 2004, 30, T. 1; 45-52
1641-6414
2449-5220
Pojawia się w:
Diagnostyka
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adaptive neurofuzzy predictive control of nuclear steam generators
Autorzy:
Ahmad, Z.
Powiązania:
https://bibliotekanauki.pl/articles/146920.pdf
Data publikacji:
2013
Wydawca:
Instytut Chemii i Techniki Jądrowej
Tematy:
neurofuzzy model
predictive control
U-tube steam generator
Opis:
The main emphasis of this paper is the application of adaptive neurofuzzy model-based predictive control, to regulate the water level in the U-tube steam generating (UTSG) unit used for electricity generation. A nonlinear predictive controller is designed on the basis of a Takagi-Sugeno fuzzy model with B-spline membership function. By on-line adaptation of the neurofuzzy model, improvement of the control performance can be achieved with the time-variant process behaviour. For this purpose, a normalized least-square algorithm is utilized which exploits the local linearity of Takagi-Sugeno fuzzy models. An optimization approach with a quadratic programing technique is used to calculate predictions of the future control actions. The effectiveness and real-world applicability of the proposed approach are demonstrated by computer simulation. The control experiments were successfully conducted for this nonlinear process with satisfactory results and performances.
Źródło:
Nukleonika; 2013, 58, 2; 301-306
0029-5922
1508-5791
Pojawia się w:
Nukleonika
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Adress for Professor Krzysztof Jan Jesionek Anniversary
Autorzy:
Lewandowski, J.
Gnutek, Z.
Badur, J.
Powiązania:
https://bibliotekanauki.pl/articles/175358.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
steam and gas turbine
power boiler
compressors
fluid-flow machinery
power plants
Opis:
This article presents professional activity of Krzysztof Jesionek within the background of his personal career in the field of heat and power engineering on Wrocław University of Technology. In particular, we present stages of scientific and professional development with an emphasis on nature Professor Jesionek’s career main driving forces as a result of his cooperation with industry and power engineering.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2014, 126; 3-20
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 366

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