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1

Experimental evaluation of the dynamic properties of an energy microturbine with defects in the rotating system

Żywica Grzegorz, Kaczmarczyk Tomasz Z.

Eksploatacja i Niezawodność

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2019

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Vol. 21, no. 4

670--678

EN

Today’s energy systems increasingly use various types of microturbines to produce electricity. A specific feature of such machines is a high-speed rotor, whose rotational speed can be higher than 100,000 rpm. Failure-free operation of highspeed microturbine rotors requires both special design and high precision during the manufacturing process. What is more, proper procedures must be followed during run-up and coast-down phases; and also, dedicated diagnostic systems have to be used. This article discusses the experimental research conducted on a 2.5 kW vapour microturbine that operated in a prototypical combined heat and power plant. A series of measurements was carried out to evaluate the dynamic performance of the machine during normal operation. After the appearance of certain defects in the rotating system, it was necessary to perform a new series of measurements in order to assess the dynamic properties of the machine. The measurements results obtained in the form of vibration velocity spectrums made it possible to define diagnostic symptoms corresponding to particular defects. Similar diagnostic symptoms can occur during the operation of this class of turbomachines.

PL

We współczesnych systemach energetycznych coraz częściej do wytwarzania energii elektrycznej stosowane są różnego typu mikroturbiny. Charakterystyczną cechą takich maszyn są wysokoobrotowe wirniki, których prędkości obrotowe mogą przekraczać nawet 100 000 obr/min. Praca wirnika w takich warunkach wymaga zastosowania specjalnych rozwiązań konstrukcyjnych i bardzo dużej precyzji wykonania, a podczas eksploatacji zachowania odpowiednich procedur przy rozruchu i odstawieniu, a także stosowania dedykowanych systemów diagnostycznych. W niniejszym artykule zostały omówione badania eksperymentalne mikroturbiny parowej o mocy 2,5 kW, pracującej w prototypowym układzie kogeneracyjnym. Wykonane pomiary obejmowały ocenę stanu dynamicznego podczas normalnej pracy maszyny oraz badania jej właściwości dynamicznych w obecności defektów układu wirującego. Uzyskane wyniki pomiarów, w postaci rozkładów częstotliwościowych drgań, pozwalają na zdefiniowanie symptomów diagnostycznych typowych dla różnych defektów, które mogą pojawić się podczas eksploatacji tej klasy maszyn wirnikowych.

2

Zastosowanie nowoczesnych tworzyw sztucznych do budowy wysokoobrotowych maszyn przepływowych

Żywica G., Kaczmarczyk T.Z., Ihnatowicz E.

Mechanik

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2018

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R. 91, nr 7

508--510

PL

Omówiono zagadnienia związane z doborem tworzyw sztucznych na wybrane elementy wysokoobrotowych maszyn przepływowych. Oprócz kryteriów stosowanych przy doborze materiału przedstawiono przykład analizy wytrzymałościowej tarczy wirnikowej z tworzywa sztucznego. Celem tych prac było zastąpienie powszechnie stosowanych stopów metali nowoczesnymi tworzywami sztucznymi, co może się przełożyć na skrócenie czasu produkcji i obniżenie kosztów.

EN

Discussed are issues related to the selection of plastics for manufacturing chosen components of high-speed fluid-flow machinery. In addition to discussing the criteria used for material selection, an exemplary strength analysis of a rotor disk made of plastic was presented. The work carried out was aimed at replacing commonly used metallic alloys with modern plastics, which in turn may shorten production time and reduce costs.

3

Design and manufacturing of micro-turbomachinery components with application of heat resistant plastics

Żywica G., Kaczmarczyk T., Ihnatowicz E., Bagiński P., Andrearczyk A.

Mechanics and Mechanical Engineering

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2018

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Vol. 22, nr 2

649--660

EN

The article discusses issues associated with the use of modern plastics for the construction of high-speed fluid-flow machines. Currently available plastics exhibit high chemical resistance as well as dimensional and shape stability across a wide temperature range. This allows them to be used for manufacturing components of micro turbomachinery, thereby reducing production time and costs. This article discusses the criteria for the selection of plastics suitable for a particular machine, namely micro turbogenerator operating in the organic Rankine cycle (ORC). In addition to the initial selection of materials based on their chemical and physical properties, strength calculations of selected turbogenerator subassemblies were carried out. The obtained results confirmed that some plastics can replace traditional materials used in the manufacture of ORC turbogenerators. This concerns, in particular, the components of the microturbine blade system. After the manufacture of a trial series of such components, it became apparent that, with appropriately chosen plastics, it is possible to shorten the machining time and reduce production costs, all while maintaining the required dimensional tolerances. The results obtained so far prove that it is possible to use plastics to produce components of modern turbomachines, for instance, parts of high-speed microturbines that have to withstand high operating temperatures.

4

Modelling and analysis of rotating systems with gas foil bearings under transient operating conditions

Żywica G., Bogulicz M., Bagiński P.

Tribologia

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2017

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nr 2

167--173

EN

Gas foil bearings are on the cutting edge of bearing systems that spread worldwide. Although it is a common practice to apply such systems to high-speed fluid-flow machinery, their modelling and analysis still pose a number of problems. This article describes the methodology used to assess dynamic properties of a rotor-bearings system supported by foil bearings. Particularly close attention has been paid to the system operation in a transitional state during which a gaseous lubricating film is formed. The conception for the description of the rotor support characteristics was implemented in a computer program that is still under development. The approach that has been taken makes it possible to analyse the system properties throughout a whole range of rotational speeds. Another approach used in the past enabled for analyses of the dynamic performance of rotors, but only on the condition that bearing operation is correct (i.e. only fluid friction in bearing is present). The new model allows for much broader analyses of bearings operation, as confirmed by the obtained results. The article discusses exemplary results of analyses and shows a way one can assess the dynamic properties of rotating machinery equipped with foil bearings even when analysed under transient operating conditions.

PL

Gazowe łożyska foliowe są innowacyjną i coraz częściej stosowaną metodą łożyskowania wysokoobrotowych wirników, ale ich modelowanie i analiza wciąż sprawia wiele trudności. W niniejszym artykule przedstawiono koncepcję ciągłego opisu właściwości dynamicznych wirnika podpartego na łożyskach foliowych. Szczególną uwagę poświęcono pracy układu w obszarze stanu przejściowego, gdy gazowy film smarny zaczyna się tworzyć. Opracowana koncepcja opisu charakterystyk podparcia wirnika została zaimplementowana w rozwijanym programie komputerowym, co umożliwia analizę właściwości układu w pełnym zakresie prędkości obrotowych. Wcześniej stosowane podejście pozwalało na analizę właściwości dynamicznych wirników tylko pod warunkiem poprawnej pracy łożyska, tzn. w obszarze tarcia płynnego. Opracowany model ma znacznie szersze zastosowanie, co zostało potwierdzone w przeprowadzonych badaniach. W artykule przedstawiono przykładowe wyniki analiz pozwalających na ocenę właściwości dynamicznych układów wirujących z łożyskami foliowymi także w stanach przejściowych.

5

Experimental research on gas foil bearings with polymer coating at an elevated temperature

Żywica G., Bagiński P., Andrearczyk A.

Tribologia

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2016

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nr 3

217--227

EN

As demand for high-performance fluid-flow machines (including micro-turbines) increases across the globe, new non-conventional bearing systems are needed. In the last years, specialized technical solutions involving the use of gas foil bearings have been progressively introduced. The application of carefully selected, thin foils as key parts of foil bearings ensures stable operation of the rotor, which is supported by such bearings, even at very high rotational speeds. The article discusses the tests performed on the foil bearings incorporating a friction relieving polymer coating. The research was conducted on an advanced test rig allowing the experiments to be run at high speeds and elevated temperatures, which is in conditions that are typical for micro-turbine operation. The measurements of bearing components’ temperature and vibration levels were carried out at various rotational speeds. The tested bearings were also assessed from the point of view of wear and durability. Conducted research demonstrated that the carefully selected materials that were used to manufacture foil bearings’ key components have successfully contributed to achieving reliable operation within a wide range of rotational speeds, providing very good dynamic properties for the rotor.

PL

W artykule omówiono badania eksperymentalne łożysk foliowych ze specjalną powłoką polimerową zmniejszającą tarcie. Powłoką polimerową została pokryta jedna strona foli ślizgowej, która współpracuje z czopem. Badania zostały wykonane na specjalistycznym stanowisku badawczym umożliwiającym prowadzenie eksperymentów przy wysokich prędkościach w podwyższonej temperaturze, a więc w warunkach typowych dla mikro-turbin. Podczas badań prowadzono pomiar temperatury elementów łożyska oraz drgań czopa przy różnych prędkościach obrotowych. Badane łożyska foliowe były również oceniane pod kątem zużycia i trwałości. Przeprowadzone badania wykazały, że przy odpowiednio dobranych materiałach łożyska foliowe mogą pracować przy minimalnym zużyciu, zapewniając bardzo dobre właściwości dynamiczne wirnika w szerokim zakresie prędkości obrotowych.

6

Prototype of the domestic CHP ORC energy system

Kicinski J., Zywica G.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2016

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Vol. 64, nr 2

417--424

EN

The Institute of Fluid-Flow Machinery (IMP PAN) in Gdansk pursues its own research in fields such as technologies that use renewable energy sources efficiently, including in particular the small-scale combined heat and power (CHP) systems. This article discusses the design concepts for the prototype of small CHP ORC (organic Rankine cycle) energy system, developed under the research project. The source of heat is a boiler designed for biomass combustion. Electricity was generated using specially designed oil-free vapour micro-turbine. The turbo-generator has compact structure and hermetical casing thanks to the use of gas bearings lubricated by working medium. All energy system components are controlled and continuously monitored by a coherent automation and control system. The article also discusses selected experimental results conducted under laboratory conditions. Thermal-flow tests were presented that allow for an assessment of the operation of energy system components. Additionally, energy performance results of the turbo-generator were given including power obtained at various cycle parameters. The achieved results have shown that the developed energy system operated in accordance with design solutions. Electricity derived from the energy system prototype was around 2 kW, with boiler’s thermal power of 25 kW. The research has also confirmed that this system can be used in a domestic environment.

7

Analiza obiegów kogeneracyjnych z silnikami tłokowymi i mikroturbinami

Cieśliński A., Kosowski K., Piwowarski M., Stępień R., Włodarski W.

Rynek Energii

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2015

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Nr 6

41--46

PL

Przeprowadzono analizę dla układów kogeneracyjnych z mikroturbinami wykorzystującymi ciepło odpadowe z silników tłokowych. Rozważono cztery główne źródła ciepła odpadowego z silników tłokowych: spaliny wylotowe, woda chłodząca silnik, olej smarny i ciepło z systemu turbodaładowania. Obliczenia przeprowadzono dla silników General Electric Jerbacher typów: J320 GS-C25 i J416 GS-B05. Uwzględniono różne czynniki robocze siłowni (zarówno “suche”, jak i “mokre”) oraz różne cycle termodynamiczne. Nasze badanie wykazały, że wykorzystując ciepło odpadowe silników, można nie tylko podgrzewać wodę, ale także wytwarzać energię elektryczną. W ten sposób można podnieść sprawność ogólną wytwarzania energii elektrycznej nawet o 20%.

EN

The analysis was carried out for Combined Heat and Power generation systems with micro-turbines power plants working on heat rejected from the reciprocating engine. There are four main sources of heat rejected from the stroke engines: exhaust gases, engine cooling water, lubricating oil and intercooler. The calculations were performed for GE Jerbacher engines of J320 GS-C25 and J416 GS-B05 types. We considered different working media (both wet and dry fluids) and different thermodynamic cycles. Our results proved that using the heat rejected from the engines is possible not only to warm up water but also to produce some electric power and, in this way, increase the total electric output by even 20%.

8

Charakterystyki cieplen łożyska foliowego pracującego w podwyższonej temperaturze w warunkach rozbiegu, wybiegu i pracy ze stałą prędkością obrotową

Bagiński P., Banaszek S., Żywica G., Kiciński J.

Mechanik

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2015

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R. 88, nr 7CD

21--28

PL

W artykule zaprezentowano pomiary drgań węzłów łożyskowych wirnika posadowionego na aerodynamicznych łożyskach foliowych oraz pomiary rozkładu temperatur łożyska podczas pracy układu wirnikowego w podwyższonej temperaturze. Przeprowadzone badania pozwalają na określenie charakterystyk pracy układu wirnikowego w różnych warunkach, ilości i rozkładu generowanego ciepła, a także własności dynamicznych łożyska. Badania mogą również posłużyć do oceny bezpieczeństwa użytkowania oraz trwałości zaproponowanego układu wirnikowego.

EN

The paper presents the bearings vibration measurements of the rotor supported by aerodynamic foil bearings and the temperature distribution in the bearing during operation at elevated temperatures. The conducted experimental investigation allows to determine the operating conditions of such a rotor system, the amount and distribution of heat as well as the dynamic properties of the bearing. The results of the studies may help to carry out an evaluation of the durability and safety-in-use of the proposed rotor system.

9

The dynamics of microturbines lubricated using unconventional agents

Kiciński J.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2015

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Vol. 63, nr 2

369--377

EN

he paper presents the research results of the microturbines dynamics with power of a few to several hundred KW. They are combined heat and power (CHP) units (generating heat and electricity) for houses and for municipalities in the form of Autonomous Energy Regions (ARE). These are key technologies for energy sector with respect to the distributed generation and for small-scale eco-power engineering. The following examples will refer only to the several selected research projects coordinated by the IMP PAN (Institute of Fluid- Flow Machinery of the Polish Academy of Sciences) in Gdansk. The paper will focus on the dynamics of rotors and bearings lubricated by means of low boiling agents, i.e., by means of turbine working medium. Analysis of hydrodynamic instability phenomena, including the development of oil whirl and oil whip has also been carried out.

10

The laboratory test stand of the ORC micro power plant

Breńkacz Ł., Bykuć S., Żywica G., Kaczmarczyk T., Bagiński P.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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2014

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nr 146

47--56

EN

The article presents the design and implementation of the laboratory test stand of the micro power plant with an Organic Rankine Cycle (ORC). The test stand was created to research different constructions of micro-turbines operating on a low-boiling agent. The electric power of these micro-turbines is 2-3 [kW]. There are measuring sensors connected to the test stand, which are necessary to collect information about the work of the whole ORC system. This laboratory test stand was built in the Szewalski Institute of Fluid Flow Machinery in Gdansk. The research on the newly constructed test stand were performed and some of the results are shown in this article.

11

Experiences from operation of various expansion devices in small scale ORC

Mikielewicz D., Wajs J., Mikielewicz J., Kosowski K.

Zeszyty Naukowe. Cieplne Maszyny Przepływowe - Turbomachinery / Politechnika Łódzka

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2014

|

nr 145

95--96

EN

The main aim of this paper was to present various expansion devices for an application in the small scale ORC system. The investigations were carried out in two parallel directions. One direction was to design and construct a device dedicated to the analyzed ORC system. The second direction was to adapt existing expansion devices for the needs of the analyzed ORC system. Four various devices were described and presented together with the experimental results. The most promising seemed to be the vapour microturbine which was built from the beginning as the device ORC system oriented.

12

The Dynamic Performance Analysis of the Foil Bearing Struture

Żywica G.

Acta Mechanica et Automatica

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2013

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Vol. 7, no. 1

58-62

EN

Foil bearings are a variety of slide bearings in which an additional set of foils is applied between journal and bush, in order to improve the selected static and dynamic properties. Engineers and researchers from all over the world investigate bearings of this type since many years - both from numerical as well as experimental point of view. Due to the complexity of construction, the reliable simulation models are all the time being searched for. This paper discusses the important stages of elaboration of the structural supporting layer numerical model of the foil bearing as well as results of verification tests. The main goal of the conducted study was assessment of reliability of the elaborated numerical model, in scope of dynamic properties. In the near future it will be used for elaboration of the numerical model of the entire foil bearing, which will take into account also phenomena in fluid-film layer. Those models will be used together to describe bearing system in operation.

13

Characteristics of utilization of biogas technology

Niemczewska J.

Nafta-Gaz

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2012

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R. 68, nr 5

293-297

EN

This paper intends to comprehensively address the methods of using the energy trapped in biogas. Efficient utilization of biogas cannot only protect the environment, but also save energy resources. The main objective of this paper is to introduce biogas technologies and to investigate the feasibility of using biogas in multiple options. The intention is to present biogas utilization methods, starting from heat production to combined heat and power generation (CHP). There are several ways to effectively utilize biogas for energy; however, the primary application in Poland is electricity generation. Electricity for onsite use or sale to the grid can be generated using a variety of different technologies, including: reciprocating internal combustion engines, gas turbines, power plants with organic Rankine cycles, microturbines, and Sterling external combustion engines. Biogas can also be upgraded to biomethane as an alternative to natural gas, using currently available and widely used biogas transforming techniques. When upgrading is performed, biomethane can be used as vehicle fuel or for injection into the natural gas grid.

PL

W artykule przedstawiono sposoby wykorzystania energii zawartej w biogazie. Efektywne wykorzystanie biogazu ma nie tylko chronić środowisko, ale także oszczędzać zasoby energii. Głównym celem pracy jest charakterystyka technologii zagospodarowania biogazu oraz zbadanie możliwości produkcji energii z biogazu z wykorzystaniem różnych technologii. Zostały przedstawione sposoby zagospodarowania biogazu, począwszy od wytwarzania energii cieplnej a skończywszy na technologiach opartych na wytwarzaniu energii elektrycznej i cieplnej w skojarzeniu. Efektywne wykorzystanie biogazu do produkcji energii elektrycznej może być generowane przy użyciu różnych technologii, w tym: tłokowych silników spalinowych, turbin gazowych, cyklu Rankine.a, mikroturbin, silników Stirling.a (zewnętrzny silnik spalinowy). Jednym ze sposobów zwiększenia efektywności wykorzystania biogazu jest jego uszlachetnianie, a następnie wtłoczenie uzyskanego w procesie biometanu do sieci dystrybucyjnej.

14

New method of analysis of dynamic state of power micro-devices

Kiciński J.

Mechanics and Mechanical Engineering

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2011

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Vol. 15, nr 3

259-271

EN

Main energy conversion machinery used and to be used in cogeneration systems are schematically described. Some assets of distributed generation are pointed out and small-scale cogeneration systems designed for energy units of distributed cogeneration are described. In the small scale, turbines and bearings are a source of specific problems connected with securing stable rotor operation. Accepted has been two kind of high speed microturbines of electric power about 3 KW with multistage axial and radial rotors supported on foil bearings. A concept which becomes more and more attractive takes into account low-boiling agent, which is normally used in the thermal cycle of the microturbine, as a lubricating liquid in the bearings (so called ORC based systems). The scope of the present article is limited to the discussion of dynamic characteristics of the selected design. The properties of the rotor combined with slide bearings (foil bearings in this particular ease) were taken under investigation. A combination of this type is a certain novelty, since a typical modal analysis of such objects refers to a rotor itself. Analysing the dynamic state of the "home" power plants requires qualitatively novel research tools. It turned out that the situation, in that the rotor - after losing its stability - stabilizes again when the rotational speed increases, is possible. This is a phenomenon determined by the author as multiple whirls.