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1
Content available remote POLAND RULES! Polska rządzi! Relacja z regat łodzi solarnych Dong Energy Solar Challenge 2014
100%
Litwin W.
Napędy i Sterowanie
|
2014
|
tom R. 16, nr 7/8
76--78
PL
W ostatnich dniach czerwca bieżącego roku w holenderskiej Fryzji odbyła się piąta edycja rozgrywanych co dwa lata regat łodzi solarnych, które noszą nazwę Dong Energy Solar Challenge. Po raz piąty wzięli w niej udział studenci Wydziału Oceanotechniki i Okrętownictwa Politechniki Gdańskiej, członkowie Koła Naukowego KORAB.
2
Content available remote Projekt i budowa regatowo-badawczej łodzi zasilanej energią słoneczną
100%
Litwin W.
Napędy i Sterowanie
|
2011
|
tom R. 13, nr 2
68-72
PL
Studenci Wydziału Oceanotechniki i Okrętownictwa Politechniki Gdańskiej oraz członkowie Koła Naukowego KORAB od kilku lat budują nietypowe jednostki pływające i biorą udział w międzynarodowych regatach.
3
Content available Water-lubricated bearings of ship propeller shafts - problems, experimental tests and theoretical investigations
100%
Litwin W.
Polish Maritime Research
|
2009
|
tom nr 4
42-50
EN
In recent years can be met ships whose propeller shaft polymer bearings are lubricated with water. It results from simplicity and associated low cost of such solution which is also environmentally friendly as no risk of pollution is involved. However the solution is not free of disadvantages. The main problem is intensive wear of bush material, occurring in certain cases. It very often results from errors of improper design and machining and mounting operations. Another problem is a limited value of its hydrodynamic load-carrying capacity, resulting from low viscosity of water used as a lubricating medium. As results from the performed research investigations, bearing of the kind is a highly sensitive unit. Problems of choosing a suitable bearing clearance, designing an optimum bush geometry, selecting a proper bush material are crucial for lifitime of the bearing.
4
Water-lubricated bearings of ship propeller shafts - problems, experimental tests and theoretical investigations
100%
Litwin W.
Polish Maritime Research
|
2009
|
tom 16
|
nr 4
EN
In recent years can be met ships whose propeller shaft polymer bearings are lubricated with water. It results from simplicity and associated low cost of such solution which is also environmentally friendly as no risk of pollution is involved. However the solution is not free of disadvantages. The main problem is intensive wear of bush material, occurring in certain cases. It very often results from errors of improper design and machining and mounting operations. Another problem is a limited value of its hydrodynamic load-carrying capacity, resulting from low viscosity of water used as a lubricating medium. As results from the performed research investigations, bearing of the kind is a highly sensitive unit. Problems of choosing a suitable bearing clearance, designing an optimum bush geometry, selecting a proper bush material are crucial for lifitime of the bearing
5
Influence of main design parameters of ship propeller shaft water-lubricated bearings on their properties
100%
Litwin W.
Polish Maritime Research
|
2010
|
tom 17
|
nr 4
EN
In recent years more and more frequently can be met ships in which propeller shaft water-lubricated polymer bearings have been applied. It results from their simplicity and associated relatively low initial and operational cost as compared with the complex classical sealed system based on oil-lubricated bearings. It is worth mentioning that the water-lubricated bearings are also environmentally friendly as no risk of pollution with lubricating oil used in classical systems, is involved. Design procedure of bearings in question based on materials made available by producers is relatively simple. However it turns out that choice of an appropriate sliding material, clearance value and optimum arrangement of lubricating grooves may greatly influence bearing’s properties. As results from the performed research investigations, bearing of the kind is a highly sensitive unit. Problems of choosing a suitable bearing clearance, designing an optimum bush geometry, selecting a proper bush material are crucial for life time of the bearing. In particular the problem is in forming hydrodynamical properties of bearing as owing to its operation in the fluid friction regime durability of bearings, the very responsible units of propulsion transmission system, can be greatly extended
6
Content available Influence of local bush wear on properties of water lubricated marine stern tube bearings
100%
Litwin W.
Polish Maritime Research
|
2011
|
tom nr 1
32-36
EN
In recent years more and more frequently can be met ships in which propeller shaft water-lubricated polymer bearings have been applied. It results from their simplicity and associated relatively low initial and operational cost as compared with the complex classical sealed system based on oil-lubricated bearings. It is worth mentioning that the water-lubricated bearings are also environmentally friendly as no risk of pollution with lubricating oil used in classical systems, is involved. Design procedure of bearings in question based on materials available from their producers is relatively simple. However the calculating of such bearings creates many problems. For calculating the hydrodynamic lubricating theory is as a rule used and elastic bush flexibility taken into account. In the case of greater loads when lubricating film is very thin to achieve a proper solution is very difficult. For this reason is proposed a novel method in which bush local wear effect can be accounted for. Such phenomenon has been observed during experimental tests of heavy-loaded water-lubricated slide bearings. With the use of the applied calculation algorithm bush local wear close to its edges can be taken into account, and - in consequence - a greater bearing capacity can be achieved.
7
Content available Influence of main design parameters of ship propeller shaft water-lubricated bearings on their properties
100%
Litwin W.
Polish Maritime Research
|
2010
|
tom nr 4
39-45
EN
In recent years more and more frequently can be met ships in which propeller shaft water-lubricated polymer bearings have been applied. It results from their simplicity and associated relatively low initial and operational cost as compared with the complex classical sealed system based on oil-lubricated bearings. It is worth mentioning that the water-lubricated bearings are also environmentally friendly as no risk of pollution with lubricating oil used in classical systems, is involved. Design procedure of bearings in question based on materials made available by producers is relatively simple. However it turns out that choice of an appropriate sliding material, clearance value and optimum arrangement of lubricating grooves may greatly influence bearing’s properties. As results from the performed research investigations, bearing of the kind is a highly sensitive unit. Problems of choosing a suitable bearing clearance, designing an optimum bush geometry, selecting a proper bush material are crucial for life time of the bearing. In particular the problem is in forming hydrodynamical properties of bearing as owing to its operation in the fluid friction regime durability of bearings, the very responsible units of propulsion transmission system, can be greatly extended.
8
Influence of local bush wear on properties of water lubricated marine stern tube bearings
100%
Litwin W.
Polish Maritime Research
|
2011
|
tom 18
|
nr 1
EN
In recent years more and more frequently can be met ships in which propeller shaft water-lubricated polymer bearings have been applied. It results from their simplicity and associated relatively low initial and operational cost as compared with the complex classical sealed system based on oil-lubricated bearings. It is worth mentioning that the water-lubricated bearings are also environmentally friendly as no risk of pollution with lubricating oil used in classical systems, is involved. Design procedure of bearings in question based on materials available from their producers is relatively simple. However the calculating of such bearings creates many problems. For calculating the hydrodynamic lubricating theory is as a rule used and elastic bush flexibility taken into account. In the case of greater loads when lubricating film is very thin to achieve a proper solution is very difficult. For this reason is proposed a novel method in which bush local wear effect can be accounted for. Such phenomenon has been observed during experimental tests of heavy-loaded water-lubricated slide bearings. With the use of the applied calculation algorithm bush local wear close to its edges can be taken into account, and - in consequence - a greater bearing capacity can be achieved
9
Content available remote Research work on water lubricated polymer hydrodynamic bearing
100%
Litwin W.
International Journal of Applied Mechanics and Engineering
|
2004
|
tom Vol. 9, no spec.
211-216
EN
The subject of this article is the conducting of the measurements on water lubricated shaft bearings. The first part of the article contains the description of the test stand, the working conditions, and the bearing specifications. The second part presents the results of the conducted measurements. The author shows the results of the experimental work: the graphs of the coefficient of friction, the pressures in the water hydrodynamic film and the shaft trajectory. The work's essential conclusion is that the water hydrodynamic lubrication is possible - as it is proven.
10
Content available remote Badania polimerowych łożysk ślizgowych wału śrubowego małej jednostki pływającej
100%
Litwin W.
Tribologia
|
2002
|
tom nr 1
341-350
PL
Referat prezentuje założenia oraz wyniki wstępnych badań teoretycznych i eksperymentalnych smarowanych wodą polimerowych łożysk ślizgowych wału śrubowego małej jednostki pływającej. Głównym problemem badawczym jest wyjaśnienie czy w smarowanych wodą panwiach wału śrubowego możliwe jest uzyskanie stabilnego smarowania hydrodynamicznego. Autor przedstawia model obliczeń teoretycznych oraz specjalne zaprojektowanie i wykonane stanowisko do badań eksperymentalnych.
EN
The matters under discussion there are problems connected with main shaft bearings of small ships. In first part there are presented initial results of research work of coefficient of friction. Tests were done on original unit with main shaft, propeller, bush and two water-lubricated bearings. In second part there are graphs (graph. 3-7) of pressures, results of numeric calculations for water lubricated bearings. In last part author describe structure of new designed test stand. Idea of testing was accepted by fame firm TENMAT. They send bearing material for free. Description of test stand. Test stand is assembled from few main parts: Main shaft with power transmission system. Main shaft is made from stainless steal. Working part (cooperating with bearing) have dimension 100 and in lenght 700 mm. Power transmission system is assembled with electric DC engine together with unit for changing rotation speed (0-10001/min.). Bearing unit. Bearing bush is 300 mm long. Across bearing we are able to pass water (salt see water) under various flow and pressure (max 6 bar). Load is static but we plan to add a unit for dynamic load. Measurement unit. We have wide measurement possibilities. We are using computer with analog input card for data recording; Measurement of work conditions: Rotation speed, Load. Water pressure and flow. Measurement results. Pressure of water (hydrodynamic or hydrostatic) in every place between shaft and bearing. It is possible because we are able to move bearing along the shaft - pressure pick-up is mounted inside shaft. Location of the shaft's center (shaft trajectory).
11
Content available remote Badania eksperymentalne polimerowego łożyska smarowanego wodą okrętowego wału śrubowego
63%
Dymarski C. , Litwin W.
Tribologia
|
2003
|
tom nr 4
125-136
PL
Referat prezentuje część wyników uzyskanych w trakcie badań eksperymentalnych polimerowego łożyska okrętowego wału głównego smarownego wodą. Zademonstrowano uzyskane w trakcie pracy badawczej wykresy współczynnika tarcia, rozkładu ciśnienia na obwodzie pomiędzy czopem a panwią oraz trajektorii środka czopa.
EN
The matters under discussion there are results of research work on water lubricated main shaft bearing of ship. Research work was done on special test stand witch has wide measurement possibilities (Fig. 1). We can record coefficient of friction, shaft trajectory, pressure between shaft and bearing, rotation speed, pressure and water flow in different condition like: rotation speed 3 to 11 [1/s], load 1 to 5 [kN], pressure of water 0,2 do 3 [bar], water flow 10 and 20 [litres/min]. Bearing was designed and made by famous producer and mounted in special bush (Fig. 2). The main problem of work was to check possibility of hydrodynamic lubrication. Some examples of results of measurements work were shown (coefficient of friction Fig. 3 and 4, pressure between shaft and bearing Fig. 5 and 6, shaft center trajectory Fig. 8, 9,10).
12
The catamarans George and Energa Solar
63%
Duda D. , Litwin W.
Polish Maritime Research
|
2007
|
tom 14
|
nr 3
EN
Since a few years students of the Faculty of Ocean Engineering and Ship Technology, Gdansk University of Technology , have designed and built untypical floating units. Until last year their efforts were focused mainly on leg-driven boats. The boats of interesting design have taken part in yearly competitions : the International Waterbike Regatta. Their advanced design made it possible to compete with the best boats from Croatia, Holland, Germany, Turkey and Italy. Recently the students have designed and built a solarenergy- driven boat. It is the catamaran Energa Solar which took part in a prestigious regatta : the Frisian Nuon Solar Challenge carried out in Holland in summer 2006
13
Content available Projekt małego promu pasażerskiego z napędem hybrydowym – koncepcja napędu i wybrane problemy gospodarowania energią
63%
Kunicka M. , Litwin W.
Napędy i Sterowanie
|
2017
|
tom R. 19, nr 10
124--128
PL
Nowoczesne i ekologiczne układy napędowe zyskują coraz większą popularność. Ze względu na wzrost świadomości społeczeństwa oraz restrykcyjne przepisy odnośnie ochrony środowiska w najbliższych latach konwencjonalne układy napędowe mogą nie zostać dopuszczone do dalszej eksploatacji. Dobór alternatywnego rozwiązania jest zależny od wielu czynników, jak na przykład od rodzaju akwenu, po którym porusza się jednostka pływająca, jej przeznaczenia, autonomiczności czy stylu pływania. Dla małego promu pasażerskiego, poruszającego się w wąskim kanale wodnym, można wybrać jedno z nowoczesnych rozwiązań, jakim jest zastosowanie napędu hybrydowego szeregowego. Poprzez badania oporowe przeprowadzone na basenie modelowym, możliwe jest również dobranie korzystnej strategii pływania, pozwalającej na ograniczenie zużycia energii, a tym samym poniesionych kosztów.
EN
Modern and eco-friendly propulsion systems are gaining more and more popularity. Due to the increase of public awareness and stringent environmental regulations, classic, conventional propulsion systems may not be allowed to use. Choosing another solution depends on many different factors, such as kind and size of water area, ship’s autonomy/destination or movement strategy. For a small inland ferry, it’s possible to choose one of the modern solutions, which is serial hybrid propulsion. Also through a research based on a ship’s resistance (hydromechanics), it is possible to select profitable movement strategy that causes decrease in costs.
14
Content available remote Wpływ chropowatości na pracę hydrodynamicznego łożyska smarowanego wodą z polimerową panwią
63%
Dymarski C. , Litwin W.
Tribologia
|
2007
|
tom nr 1
37-48
PL
Artykuł dotyczy łożysk z polimerowymi panwiami smarowanymi wodą. Celem realizowanych badań było eksperymentalne zbadanie wpływu wysokości i ułożenia chropowatości na powierzchni panwi na pracę smarowanego wodą łożyska hydrodynamicznego. Wszystkie badania eksperymentalne zostały wykonane na specjalnym stanowisku badawczym na Wydziale Oceanotechniki i Okrętownictwa Politechniki Gdańskiej. Podczas badań przetestowano trzy pary materiałów. Każda para miała panew wykonaną z jednakowego materiału, luz średnicowy był prawie taki sam (tabela), a różniły się one ułożeniem nierówności i jej wysokością. Przeprowadzone badania eksperymentalne wykazały, że ułożenie nierówności ma drugorzędne znaczenie (przedstawiono wykresy trajektorii osi wału i oporów ruchu), większy wpływ na opory ruchu ma wysokość chropowatości.
EN
The article deals with water lubricated main shaft bearings. The main idea of experimental test made recently was to check influence of roughness height and direction on work of water lubricated hydrodynamic bearing. AH experimental tests were made on special test stand design and built at the Faculty of Ocean Engineering and Ship Technology of the Gdansk University of Technology. During the tests three pairs of bearings were tested. Every pair has the same bearing bush material and almost the same diameter clearance. The difference was in roughness direction and height. Conducted measurements proved that roughness direction hasn't big influence on bearing work (pictures of resistance of movement and shaft center trajectories). Much more important is roughness height especially during run in period.
15
Content available remote Numeryczna analiza trojwymiarowgo przepływu w polimerowym łożysku smarowanym wodą
63%
Flaszyński P. , Litwin W.
Tribologia
|
2007
|
tom nr 1
49-56
PL
Praca prezentuje wyniki obliczeń przepływu trójwymiarowego w obszarze szczeliny łożyska wraz z komorą zasilającą i spływową. Obliczenia wykonano przy zastosowaniu programu FLUENT. Przedstawiono wartości lokalne w postaci rozkładu ciśnienia i temperatury w łożysku oraz charakterystyki globalne: wartości sił i masowego natężenia przepływu. Wyniki obliczeń przedstawiono na tle danych eksperymentalnych dla jednej z wybranych konfiguracji łożyska.
EN
The article deals with water lubricated main shaft bearings. The main idea of this article was to check and present the possibilities of modern CFD software - FLUENT 6.2 as a tool for calculation of hydrodynamic bearings. The results of conducted calculations were compared to measurements. All experimental tests were made on special test stand design and built at the Faculty of Ocean Engineering and Ship Technology of the Gdansk University of Technology. The results of calculated load capacity are similar. The value difference was about 30%. Bigger difference was in measured and calculated pressure field. Probably problem was in measured values.
16
Content available remote Hybrydowe łożysko okrętowego wału głównego smarowane wodą - koncepcja i pierwsze badania eksperymentalne
63%
Dymarski C. , Litwin W.
Tribologia
|
2004
|
tom nr 3
91-99
PL
Referat dotyczy okrętowych łożysk wałów śrubowych z polimerową panwią smarowanych wodą. Przedstawiono w nim wybrane wyniki badań łożyska z typową panwią oraz łożyska z tą samą panwią, ale z nieco zmienionym kształtem rowków smarnych. Zmiana ta, wprowadzona przez autorów, miała na celu polepszenie warunków wytworzenia się hydrodynamicznego filmu smarnego i zapewnienia pracy łożyska przy tarciu płynnym, czego nie stwierdzono w łożysku typowym. Przeprowadzone wstępne badania laboratoryjne potwierdziły skuteczność wprowadzonych zmian i uzyskanie tarcia płynnego w łożysku.
EN
The research test stand for water lubricated main shaft bearings was designed and built between the years 2000-2002 on the Faculty of Ocean Engineering and Ship Technology on the Gdansk University of Technology. It is possible to test the slide bearings with the internal diameter of 100 mm and the length up to 400 mm in it. Test stand gives a wild measurement possibilities. It was designed with the hope of conducting the measurements of the pressure in the bearing interspace in at a few transversal surfaces. Thanks to it, it is possible to measure pressure filed. Additionally, it was possible to register the trajectory of the shaft, the friction force, the flow and the pressure of the flowing water. First the bearing bush with grooves (Fig. 3), the inside diameter of 100 and the length of 300 mm, was test. It was a typical bearing for main shafts of small ships. The diameter clearance was 0,7 mm [L. 4]. As it was shown (Fig. 1, 4 and 5) the increase of hydrodynamic pressure was small because of influence of grooves. That was a reason why the shape o bearing bush was changed. The ends of two lower grooves were glued on out flow side for flow blockage and increasing of hydrostatic lubrication. The ends of three upper grooves were blocked on water inflow side for reducing pressures in upper part of bearing interspace. After that measured pressure in water film was totally different (Fig. 6,7). Increasing of hydrodynamic pressure is much bigger then in bearing with open groves, but different then in bearing with solid bush (Fig. 2).
17
Energy efficient small inland passenger shuttle ferry with hybrid propulsion - concept design, calculations and model tests
63%
Kunicka M. , Litwin W.
Polish Maritime Research
|
2019
|
tom 26
|
nr 2
EN
In recent years, there has been a significant development in “green” and energy efficient propulsion systems, which fits into the general trend of environmentally friendly “green shipping”. The pursued goal is to construct a safe passenger ship that is low in energy demand and equipped with a highly energy efficient, emission-free propulsion system. The paper presents main problems encountered by designers of a small, hybrid-powered ferry powered lithium batteries. The conducted research allowed to create a design of an energy efficient hull shape, which decreases the demand for energy. Completed remote control model tests resulted in a proposal of an energy efficient and safe propulsion system with good manoeuvring capabilities. Measurements completed on an existing ferry permitted completing energy balance and forming an energy management policy.The paper contains the emission calculations computed for the existing ferry that are necessary for the environmental impact analysis. The soon to be constructed, newly designed vessel will provide a valuable contribution to hybrid-propulsion, energy management and unmanned technologies research
18
Content available Attempt at evaluating the influence of bending stress on shaft wear processes in water lubricated sliding bearing with a rubber bushing
63%
Piątkowska E. , Litwin W.
Tribologia
|
2017
|
tom nr 1
81--86
EN
Water lubricated bearings find increasingly wide application in shipbuilding or the hydropower industry, with the popularity stemming from their numerous advantages. Unfortunately, as it turns out, water lubricated bearings do not always meet expectations, because, on occasion, they become subject to intense, premature wear, which requires costly repair. One of the still unexplained phenomena is the process of excessive bearing wear, in particular, that of shaft journal co-working with rubber bushings. The research goal was to evaluate the influence of shaft bending stress on the degree of its wear. Experimental tests were carried out on a purpose-designed test stand. The results of the first test series confirmed that the shaft bending stresses do have impact on the magnitude of wear.
PL
Łożyska smarowane wodą coraz powszechniej stosowane są w okrętownictwie czy energetyce wodnej. Wynika to z wielu zalet takiego rozwiązania. Niestety okazuje się, że nie zawsze łożyska smarowane wodą są w stanie sprostać oczekiwaniom i czasem dochodzi do ich intensywnego, przedwczesnego zużycia i konieczne staje się przeprowadzenie kosztownego remontu. Jednym z niewyjaśnionych dotąd zjawisk jest proces nadmiernego zużycia łożyska, a zwłaszcza czopa wału współpracującego z gumową panwią. Za cel badawczy postawiono sobie zbadanie wpływu naprężeń zginających występujących w wale na stopień jego zużycia. Badania eksperymentalne przeprowadzono na specjalnie zaprojektowanym stanowisku badawczym. Wyniki pierwszej serii badań potwierdziły, że naprężenia zginające w wale mają wpływ na wielkość zużycia.
19
Content available remote Napęd i zasilanie hybrydowe niewielkich jednostek pływających
63%
Leśniewski W. , Litwin W.
Napędy i Sterowanie
|
2013
|
tom R. 15, nr 5
76--81
PL
W ostatnich latach jesteśmy świadkami niezwykłego rozwoju praktycznie wszystkich dziedzin nauki. Dzięki temu zwłaszcza w krajach wysoko rozwiniętych projektowane i produkowane są nowe maszyny i urządzenia o coraz bardziej niezwykłych możliwościach. Postęp nie ominął okrętownictwa. Coraz ostrzejsze normy dotyczące ochrony środowiska oraz rosnące ceny paliw spowodowały, że podczas projektowania nowych jednostek oraz modernizacji starszych coraz większą wagę przywiązuje się do ich konstrukcji oraz przewidywanych kosztów eksploatacji. Należy również pamiętać o tym, że rodzaj zastosowanego napędu może mieć decydujący wpływ na to, czy jednostka zostanie dopuszczona do eksploatacji zwłaszcza na obszarach objętych ochroną, na przykład programem Natura 2000. Przeglądając literaturę fachową dotyczą okrętownictwa, coraz częściej można znaleźć artykuły, w tytułach których pojawiają się zwroty no emission, zero emission bądź green ship. Świadczy to o tym, że większą niż kiedyś wagę przywiązuje się do tak zwanych „czystych technologii”.
20
Content available The catamarans George and Energa Solar
63%
Duda D. , Litwin W.
Polish Maritime Research
|
2007
|
tom nr 3
3-6
EN
Since a few years students of the Faculty of Ocean Engineering and Ship Technology, Gdansk University of Technology , have designed and built untypical floating units. Until last year their efforts were focused mainly on leg-driven boats. The boats of interesting design have taken part in yearly competitions : the International Waterbike Regatta. Their advanced design made it possible to compete with the best boats from Croatia, Holland, Germany, Turkey and Italy. Recently the students have designed and built a solarenergy-driven boat. It is the catamaran Energa Solar which took part in a prestigious regatta : the Frisian Nuon Solar Challenge carried out in Holland in summer 2006.
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