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Wyszukujesz frazę "Kowalski, J." wg kryterium: Autor

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    Wyświetlanie 1-10 z 10
    Tytuł:
    ANN based evaluation of the NOx concentration in the exhaust gas of a marine two-stroke diesel engine
    Autorzy:
    Kowalski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/258708.pdf
    Data publikacji:
    2009
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    artificial neural network
    marine two-stroke engine
    NOx concentration
    Annex VI to Marpol Convention
    Opis:
    The article presents results of a study on the possible application of artificial neural networks (ANNs) to the evaluation of NOx concentration in the exhaust gas of a marine two-stroke Diesel engine. A concept is presented how to use the ANN as an alternative to direct measurements carried out on a ship at sea. Methods of proper ANN selection, configuration and training are presented. Also included are the results of laboratory tests, performed to obtain data for ANN training and tests, and the results obtained from modelling certain processes with the aid of selected ANNs. As a result of the performed investigations, an ANN was constructed and trained to calculate NOx concentration in the Diesel engine exhaust gas based on the engine operation parameters measured with an average error of 1.83% , and the fuel consumption measured with an average error of 1.12%.
    Źródło:
    Polish Maritime Research; 2009, 2; 60-66
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An experimental study of emission and combustion characteristics of marine diesel engine with fuel injector malfunctions
    Autorzy:
    Kowalski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/260092.pdf
    Data publikacji:
    2016
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    marine diesel engine
    exhaust gas composition
    toxic emission
    laboratory investigation
    fuel injector malfunctions
    Opis:
    The presented paper shows the results of the laboratory study on the relation between chosen malfunctions of a fuel injector and composition of exhaust gas from the marine engine. The object of research is a marine 3-cylinder, four-stroke, direct injection diesel engine with an intercooler system. The engine was loaded with a generator and supercharged. The generator was electrically connected to the water resistance. The engine operated with a load between 50 kW and 250 kW at a constant speed. The engine load and speed, parameters of the turbocharger, systems of cooling, fuelling, lubricating and air exchange, were measured. Fuel injection and combustion pressures in all cylinders of the engine were also recorded. Exhaust gas composition was recorded by using a electrochemical gas analyzer. Air pressure, temperature and humidity were also recorded. Emission characteristics of the engine were calculated according to ISO 8178 standard regulations. During the study the engine operated at the technical condition recognized as „working properly” and with simulated fuel injector malfunctions. Simulation of malfunctions consisted in the increasing and decreasing of fuel injector static opening pressure, decalibration of fuel injector holes and clogging 2 neighboring of 9 fuel injector holes on one of 3 engine cylinders.
    Źródło:
    Polish Maritime Research; 2016, 1; 77-84
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    An experimental study of emission and combustion characteristics of marine diesel engine in case of cylinder Valves leakage
    Autorzy:
    Kowalski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/259195.pdf
    Data publikacji:
    2015
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    marine diesel engine
    exhaust gas composition
    emission
    exhaust gas valve leakage
    inlet valve leakage
    Opis:
    Presented paper shows the results of the laboratory tests on the relationship between throttling of both air intake duct and exhaust gas duct and a gaseous emission from the marine engine. The object of research is a laboratory, four-stroke, DI diesel engine, operated at loads from 50 kW to 250 kW at a constant speed equal to 750 rpm. During the laboratory tests over 50 parameters of the engine were measured with its technical condition recognized as a „working properly” and with simulated leakage of both air intake valve and exhaust gas valve on the second cylinder. The results of this laboratory research confirm that the leakage of cylinder valves causes no significant changes of the thermodynamic parameters of the engine. Simulated leakages through the inlet and exhaust valve caused a significant increase in fuel consumption of the engine. Valve leakages cause an increase of the exhaust gas temperature behind the cylinder with leakage and behind other cylinders. The exhaust gas temperature increase is relatively small and clearly visible only at low loads of the engine. The increase of the temperature and pressure of the charging air behind the intercooler were observed too. Charging air temperature is significantly higher during the engine operation with inlet valve leakage. The study results show significant increases of the CO, NOx and CO2 emission for all the mentioned malfunctions. The conclusion is that the results of measurements of the composition of the exhaust gas may contain valuable diagnostic information about the technical condition of the air intake duct and the exhaust gas duct of the marine engine.
    Źródło:
    Polish Maritime Research; 2015, 3; 90-98
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The effect of notch depth on CTOD values in fracture tests of structural steel elements
    Autorzy:
    Kowalski, J.
    Kozak, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/258854.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    brittle fracture
    CTOD
    numerical modelling
    laboratory tests
    Opis:
    In elements of steel structures working at low temperatures, there is a risk of appearance of brittle fracture. This risk is reduced through the use of certified materials having guaranteed strength at a given temperature. A method which is most frequently used to determine brittle fracture toughness is the Charpy impact test, preformed for a given temperature. For offshore structures intended to work in the arctic climate, the certifying institutions more and more often require Crack Tip Opening Displacement (CTOD) tests instead of conventional impact tests, especially for steel and welded joints of more than 40 mm in thickness in the case of high-strength steel, and more than 50 mm for the remaining steels. The geometry of specimens and the test procedure are standardised; however, these standards provide some margin for specimen notch depth. The paper analyses the effect of notch depth difference, within the range permitted by the standards, on the recorded CTOD values of a given material. The analysis was performed via numerical modelling of destruction of specimens with different notch geometries and further verification of the obtained numerical results in laboratory tests. The calculations were carried out at the Academic Computer Centre in Gdansk.
    Źródło:
    Polish Maritime Research; 2018, 2; 85-91
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Numerical model of plastic destruction of thick steel structural elements
    Autorzy:
    Kowalski, J.
    Kozak, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/259652.pdf
    Data publikacji:
    2018
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    impact strength
    numerical modeling
    steel structural elements
    Opis:
    In the shipbuilding industry, the risk of brittle fracture of the structure is limited by using certified materials with specified impact strength, determined by the Charpy method (for a given design temperature) and by supervising the welding processes (technology qualification, production supervision, non-destructive testing). For off-shore constructions, classical shipbuilding requirements may not be sufficient. Therefore, the regulations used in the construction of offshore structures require CTOD tests for steel and welded joints with a thickness greater than 40 mm in the case of high strength steel and more than 50 mm in the case of other steels. Classification societies do not accept CTOD test results of samples with a thickness less than the material tested. For this reason, the problem of theoretical modeling of steel structure destruction process is a key issue, because laboratory tests for elements with high thickness (in the order of 100 mm and more) with a notch are expensive (large samples, difficulties in notching), and often create implementation difficulties due to required high load and range of recorded parameters. The publication will show results and conclusions from numerical modeling of elastic properties for steel typical for offshore applications. Calculations were carried out at the Academic Computer Centre in Gdańsk.
    Źródło:
    Polish Maritime Research; 2018, 2; 78-84
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The thermal state modelling of cylinder liner of marine two-stroke combustion engine
    Autorzy:
    Kowalski, J.
    Tarełko, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/259669.pdf
    Data publikacji:
    2006
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    silniki okrętowe
    elementanre metody równowagi
    stan cieplny
    tuleja cylindrowa
    ship engine
    elementary balance method
    thermal state
    cylinder liner
    Opis:
    This paper presents a two-dimensional model of heat flow through structural elements of cylinder of two-stroke cross-head engine of longitudinal scavenging, obtained with the use of the elementary balance method. Special attention was paid to the modelling of temperature distribution within engine cylinder liner of "wet" construction. For modelling the unsteady heat flow multi-dimensional equations with Dirichlet - Fourier boundary conditions, were used. For the Fourier boundary conditions in the engine cylinder space local values of convective and radiant heat-transfer coefficients were applied. For calculations the KM3R method of solving differential equations, based on the elementary balance method, was used. Modelling results have been presented in the form of the temperature field of engine cylinder structural elements in function of the changeable angle of crankshaft position.
    Źródło:
    Polish Maritime Research; 2006, 2; 15-20
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Problems of determination of welding angular distortions of T - fillet joints in ship hull structures
    Autorzy:
    Kozak, J.
    Kowalski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/258738.pdf
    Data publikacji:
    2015
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    welding deformations
    ship structure welding
    angular distortions in welded T-joints
    Opis:
    Ship hull structure elements are usually joined by welding. Welding distortions may cause many problems during manufacturing process. In the literature a wide spectrum of suggestions has been proposed for correct estimation of welding deformation , particularly angular ones , in the fillet welded T- joints. In this work a verification of certain methods selected from the literature is presented basing upon the results of the laboratory measurements. To this end, values determined on the basis of engineering hypotheses have been compared with those obtained from the laboratory tests.
    Źródło:
    Polish Maritime Research; 2015, 2; 79-85
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    The influence of manufacturing oversizing on postwelding distortions of the fillet welded joint
    Autorzy:
    Kozak, J.
    Kowalski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/259726.pdf
    Data publikacji:
    2015
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    welding distortion
    shipbuilding welding
    welding angular distortion
    Opis:
    Welding process is basic joining technique in shipbuilding. Such method generated welding distortions which cause a lot of problems during the manufacturing process. In the literature it is proposed wide spectrum of suggestions for a correct estimation of welding deformation in particular angular deformation in the fillet welded T joint. In the work influence of oversizing of weld on angular distortions of joint is presented basing upon of the results of the laboratory measurements. Values determined on the basis of literature hypotheses are compared with the one obtained from the laboratory test.
    Źródło:
    Polish Maritime Research; 2015, 4; 59-63
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Energy efficient and environmentally friendly hybrid conversion of inland passenger vessel
    Autorzy:
    Litwin, W.
    Leśniewski, W.
    Kowalski, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/259006.pdf
    Data publikacji:
    2017
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    ship propulsion
    hybrid propulsion
    green shipping
    zero emission
    solar power
    Opis:
    The development and growing availability of modern technologies, along with more and more severe environment protection standards which frequently take a form of legal regulations, are the reason why attempts are made to find a quiet and economical propulsion system not only for newly built watercraft units, but also for modernised ones. Correct selection of the propulsion and supply system for a given vessel affects significantly not only the energy efficiency of the propulsions system but also the environment – as this selection is crucial for the noise and exhaust emission levels. The paper presents results of experimental examination of ship power demand performed on a historic passenger ship of 25 m in length. Two variants, referred to as serial and parallel hybrid propulsion systems, were examined with respect to the maximum length of the single-day route covered by the ship. The recorded power demands and environmental impact were compared with those characteristic for the already installed conventional propulsion system. Taking into account a high safety level expected to be ensured on a passenger ship, the serial hybrid system was based on two electric motors working in parallel and supplied from two separate sets of batteries. This solution ensures higher reliability, along with relatively high energy efficiency. The results of the performed examination have revealed that the serial propulsion system is the least harmful to the environment, but its investment cost is the highest. In this context, the optimum solution for the ship owner seems to be a parallel hybrid system of diesel-electric type.
    Źródło:
    Polish Maritime Research; 2017, 4; 77-84
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Multi-source-supplied parallel hybrid propulsion of the inland passenger ship STA.H. Research work on energy efficiency of a hybrid propulsion system operating in the electric motor drive mode
    Autorzy:
    Kowalski, J.
    Leśniewski, W.
    Litwin, W.
    Powiązania:
    https://bibliotekanauki.pl/articles/259623.pdf
    Data publikacji:
    2013
    Wydawca:
    Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
    Tematy:
    hybrid ship propulsion
    ship propulsion
    Opis:
    In the Faculty of Ocean Engineering and Ship Technology, Gdansk University of Technology, design has recently been developed of a small inland ship with hybrid propulsion and supply system. The ship will be propelled by a specially designed so called parallel hybrid propulsion system. The work was aimed at carrying out the energy efficiency analysis of a hybrid propulsion system operating in the electric motor drive mode and at performing the noise pollution measurements. The performed investigations have shown that a significant impact on the efficiency and on the acoustic emission has the type of belt transmission applied.
    Źródło:
    Polish Maritime Research; 2013, 3; 20-27
    1233-2585
    Pojawia się w:
    Polish Maritime Research
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-10 z 10

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