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Wyświetlanie 1-10 z 10
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:
Model dynamiczny wytwornicy spalin z symulowanymi uszkodzeniami
Dynamic model of gas generator with faults simulations
Autorzy:
Grządziela, A.
Powiązania:
https://bibliotekanauki.pl/articles/211170.pdf
Data publikacji:
2010
Wydawca:
Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
Tematy:
silnik turbinowy
drgania
modelowanie
gas turbine engine
vibration
modelling
Opis:
W artykule przedstawiono metodę modelowania wirnika wytwornicy spalin silnika turbinowego wraz z wprowadzonymi obciążeniami pochodzącymi m.in. od niewyrównoważenia wirnika. Model umożliwia wprowadzenie wirtualnego przemieszczenia osi wału wirnika, statycznego i dynamicznego niewyrównoważenia w zakresie parametrów eksploatacyjnych charakterystycznych dla rzeczywistego silnika. Równania ruchu uwzględniające oddziaływania zewnętrzne zaimplementowano do środowiska Matlab Simulink. Model wirnika pozwala na transmisję momentu napędowego zarówno w symulowanym procesie rozruchu zimnego jak i gorącego. Podstawowymi oddziaływaniami dynamicznymi występującymi w modelu są: moment napędowy, aerodynamiczne momenty oporowe, pionowe i poziome siły działające na wsporniki łożysk, oddziaływania wynikające z niewyrównoważenia mającego swoje źródło w zmianie stanu technicznego wirnika. Uzyskane wyniki przebiegów czasowych parametrów drganiowych oraz ich widma zostały zidentyfikowane z wynikami badań rzeczywistego silnika pracującego na okręcie, co było jednym z głównych celów badań. Wyniki wykazały wysoką zgodność oraz wrażliwość na wprowadzane wartości brzegowe potwierdzające przydatność modelu w diagnostyce technicznej. Ważnym atutem modelu jest brak jego wrażliwości na zewnętrzne oddziaływania zakłócające środowiska morskiego. Uzyskany model podczas identyfikacji potwierdził swoją wrażliwość zarówno na zmienne parametry ruchu jak i zadane oddziaływania zmieniające jego stan techniczny.
The paper presents a method of modelling of gas generator rotors at the presence of virtually introduced dynamics loads, like unbalancing effects. The rotors model provides opportunities for introducing shaft displacements, static and dynamic unbalancing and rotations similar to those observed in a real object. The equations of motion, taking into account the action of external agents, were implemented to the Matlab Simulink software. In the rotors model, the driving torque is transmitted from the cold and hot start processes. The following actions were introduced to the proposed dynamic model: main engine driving torque, aeorodynamic antitorques, horizontal and vertical forces, the action resulting from changes in relative positions of load-carrying bearings and thrust bearings in the rotors line, the action of the unbalancing coming from changes of technical state. The obtained time-histories and their spectra were compared with the experimental results of the tests performed on the marine testing ground. A basic goal of modelling is the identification of the diagnostic model. In the reported case, comparing the results of the empirical studies and the simulations has proved good applicability of the proposed model. The obtained results confirmed model sensitivity to changes of technical state of the object and varying input parameters. A vital property of the model was the insensibility of the unbalancing symptom to the action of assumed environmental disturbances, such as sea environment forces. The performed model identification confirmed its sensitivity to changing parameters of motion and external actions.
Źródło:
Biuletyn Wojskowej Akademii Technicznej; 2010, 59, 4; 71-83
1234-5865
Pojawia się w:
Biuletyn Wojskowej Akademii Technicznej
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Correction of the dynamic errors of a gas sensor based on the dynamic model with averaged parameters
Autorzy:
Urzędniczok, H.
Powiązania:
https://bibliotekanauki.pl/articles/114136.pdf
Data publikacji:
2016
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
gas sensor
response time
dynamic properties
dynamic error correction
Opis:
The paper presents a numerical method of dynamic error correction applied to a measuring transducer of gas concentration with a typical sensor based on tin dioxide. The work describes research of the dynamic properties of the transducer. Its response time is approximately 8 to 10 minutes, which may be not acceptable in many applications. A parametric model of the transducer dynamics has been developed and an adequate correction algorithm is proposed. The obtained results of the dynamic correction based on the proposed method are compared with those achieved previously by applying a neural network algorithm. Despite the simplicity of the used model, the proposed method allows a significant decrease in the transducer response time.
Źródło:
Measurement Automation Monitoring; 2016, 62, 7; 214-217
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Mathematical modelling of dynamic processes in gas transmission
Autorzy:
Prytula, N.
Powiązania:
https://bibliotekanauki.pl/articles/411157.pdf
Data publikacji:
2015
Wydawca:
Polska Akademia Nauk. Oddział w Lublinie PAN
Tematy:
transmission system
compressor station
optimal operating mode
gas flow model
network model
piping diagram
finite element method
Opis:
The problem of finding the parameters of the gas transmission system in terms of its operations under unsteady operating modes are considered. We show mathematical models of gas flows in the basic facilities in the system with a complicated piping diagram. The solution is built to solve a system of partial differentia equations with the finite element method of large dimension with boundary conditions, some of which are designed in the process of solving the system of equations. This is due to the provision of technical and technological constraints on the pressure of the controlled points of the system. On the resistance to finding a solution significantly affects a step of the time coordinate. The proposed algorithm in the editing process of flow diagrams provides an increase in stability of solving systems of equations, and significantly reduces the time for the simulation.
Źródło:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes; 2015, 4, 3; 57-63
2084-5715
Pojawia się w:
ECONTECHMOD : An International Quarterly Journal on Economics of Technology and Modelling Processes
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Physicochemical mechanisms of mineral nanoparticles effects on pulmonary gas/liquid interface studied in model systems
Autorzy:
Kondej, D.
Sosnowski, T. R.
Powiązania:
https://bibliotekanauki.pl/articles/110409.pdf
Data publikacji:
2014
Wydawca:
Politechnika Wrocławska. Oficyna Wydawnicza Politechniki Wrocławskiej
Tematy:
inhalation
nanoparticles
gas-liquid interface
dynamic surface tension
Opis:
Inhaled mineral nanoparticles which are deposited on the lung surface may influence the gas/liquid barrier and the pulmonary surfactant (PS) which constitutes the vital element of the respiratory system. This research is focused on the physicochemical effects caused by selected clay nanoparticles (bentonite, halloysite, montmorillonites) interacting with PS and changing its original surface activity. Using three measuring methods (pulsating bubble technique, Langmuir balance and drop shape analysis), we demonstrated the influence of different mineral nanoparticles on the dynamic surface tension of animal-derived PS material (Survanta®) and main surfactant phospholipid (DPPC). The results which are dependent on material properties and concentration allow to hypothesize possible pathways of health effects from inhalation of mineral nanoparticles. This may help to set the guidelines in defining occupational safety standards and methods of protection of the respiratory system against inhaled mineral dusts.
Źródło:
Physicochemical Problems of Mineral Processing; 2014, 50, 1; 57-69
1643-1049
2084-4735
Pojawia się w:
Physicochemical Problems of Mineral Processing
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:
Wpływ rezydualnego nasycenia gazem poniżej stwierdzonego kontaktu woda–gaz na proces eksploatacji złoża
Impact of residual gas saturation below the specified water-gas contact on the production process
Autorzy:
Tuczyński, Tomasz
Podsobiński, Daniel
Stopa, Jerzy
Powiązania:
https://bibliotekanauki.pl/articles/1834112.pdf
Data publikacji:
2020
Wydawca:
Instytut Nafty i Gazu - Państwowy Instytut Badawczy
Tematy:
rezydualna strefa nasycenia gazem
krytyczne nasycenie gazem
dynamiczny model złoża
wodnonaporowy system energetyczny złoża
residual gas zone
critical gas saturation
dynamic reservoir model
water drive mechanism
Opis:
Natural gas fields over millions of years are exposed to various geological factors that affect their final state and shape. It happens that after some time of production, the reservoir has additional energy and greater gas resources than originally expected. The reason for this may be residual gas saturation below the specified gas–water contact, which has not been included in previous analyzes. Disregarding the residual hydrocarbon zone may lead to erroneous conclusions about resources, recovery factors and water breakthrough time. In this paper the residual gas zone impact on the production process from a real gas-condensate reservoir has been analyzed. The calculations were conducted using a dynamic reservoir model created in Eclipse numerical simulator. For the purpose of the analysis, 6 dynamic models were made. On their basis, an analysis of the impact on cumulative gas and water production was carried out for parameters such as: critical gas saturation in the residual zone and volume of aquifer. Based on the presented example, the overall gas initial in place after taking into account the residual zone has increased about 19%. However, the impact of the residual gas zone on cumulative gas production is not clearcut and its presence can have a positive as well as negative impact on the cumulative gas production. The size and type of the impact resulting from presence of the residual gas zone is directly related to the geological and reservoir conditions in the given reservoir and the way of production operation. The obtained results indicate also that the residual gas zone may affect the water breakthrough time in production wells as well as total volume of produced water.
Źródło:
Nafta-Gaz; 2020, 76, 9; 585-591
0867-8871
Pojawia się w:
Nafta-Gaz
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Development of Turboshaft Engine Adaptive Dynamic Model: Analysis of Estimation Errors
Autorzy:
Yepifanov, Sergiy
Bondarenko, Oleksiy
Powiązania:
https://bibliotekanauki.pl/articles/36807197.pdf
Data publikacji:
2022
Wydawca:
Sieć Badawcza Łukasiewicz - Instytut Lotnictwa
Tematy:
turbine engine
turboshaft
gas generator
dynamic model
engine time constant
identification
estimation error
design of experiment
Opis:
One of the most perspective directions of aircraft engine development is related to implementing adaptive automatic electronic control systems (ACS). The significant elements of these systems are algorithms of matching of mathematical models to actual performances of the engine. These adaptive models are used directly in control algorithms and are a combination of static and dynamic sub-models. This work considers the dynamic sub-models formation using the Least Square method (LSM) on a base of the engine parameters that are measured in-flight. While implementing this function in the (ACS), the problem of checking the sufficiency of the used information for ensuring the required precision of the model arises. We must do this checking a priori (to determine a set of operation modes, the shape of the engine test impact and volume of recorded information) and a posteriori. Equations of the engine models are considered. Relations are derived that determine the precision of parameters of these models’ estimation depending on the precision of measurement, the composition of the engine power ratings, and durability of observations, at a stepwise change of fuel flow. We present these relations in non-dimensional coordinates that make them universal and ready for application to any turboshaft engine.
Źródło:
Transactions on Aerospace Research; 2022, 4 (269); 59-71
0509-6669
2545-2835
Pojawia się w:
Transactions on Aerospace Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Modeling atmosphere composition and determining explosibility in a sealed coal mine volume
Modelowanie składu powietrza i określanie niebezpieczeństwa wybuchu w zamkniętej przestrzeni w obrębie kopalni węgla
Autorzy:
Cheng, J.
Luo, Y.
Powiązania:
https://bibliotekanauki.pl/articles/220237.pdf
Data publikacji:
2014
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
powietrze w odizolowanej części kopalni
niebezpieczeństwo wybuchu gazów kopalniach
model symulacyjny
dynamiczne zmiany składu powietrza
mine sealed atmosphere
mine gas explosibility
simulation model
dynamic atmosphere changes
Opis:
Explosions originated from or around the sealed areas in underground coal mines present a serious safety threat. The explosibility of the mine atmosphere depends on the composition of oxygen, combustible and inert gases. In additional, the composition in the inaccessible sealed areas change with time under various factors, such as gases emissions, air leakage, inert gases injected, etc. In order to improve mine safety, in this paper, a mathematical model based on the control volume approach to simulate the atmosphere compositions is developed, and the expanded Coward explosibility triangle diagram is used to assess the mine gas explosion risk. A computer program is developed to carry out the required computations and to display the results. In addition, the USBM explosibility diagram is also included in the program to serve as a double check.
Wybuchy powstające wewnątrz lub wokół zamkniętych (odizolowanych) regionów w podziemnych kopalniach węgla stanowią poważne zagrożenie. Możliwość wystąpienia wybuchu powietrza kopalnianego uzależniona jest od proporcji zawartego w nim tlenu, gazów palnych i gazów obojętnych. Ponadto, skład atmosfery wewnątrz zamkniętych odizolowanych przestrzeni ulega zmianom w czasie pod wpływem różnorakich czynników: wydzielanie gazów, przecieki powietrza, doprowadzanie gazów obojętnych. Dla poprawy bezpieczeństwa pracy w kopalni opracowano model matematyczny bazujący na metodzie objętości kontrolnej dla symulacji składu powietrza. Rozszerzony wykres Cowarda wskazujący skłonność do wybuchu wykorzystany został do oszacowania ryzyka wystąpienia wybuchu gazów kopalnianych. Opracowano program komputerowy który wykonuje niezbędne obliczenia i wyświetla wyniki. Ponadto, dla dodatkowego potwierdzenia wyników wykorzystano wykres USBM obrazujący niebezpieczeństwo wybuchu.
Źródło:
Archives of Mining Sciences; 2014, 59, 1; 25-40
0860-7001
Pojawia się w:
Archives of Mining Sciences
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-10 z 10

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