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EN
Is the world’s power engineering at a crossroads? Does the rapid development of new emerging fields such as the Internet of Things, smart city or e-mobility make us take a completely different point of view on the world’s energy future? What are our visions and development forecasts related to this? Who is right, Exxon Mobil Corporation or the visionary investor Elon Musk? The author of this article is trying to find answers to these and many other questions. In the long-term perspective, a transition from centralised power generation to distributed power generation seems to be inevitable, and that is the central message of this article. The article also presents the situation of the Polish power engineering against the background of global trends, as well as proposals for solving the smog problem using anti-smog technologies developed at the Institute of Fluid-Flow Machinery of the Polish Academy of Sciences in Gdańsk and by launching a pilot project that will cover 1,000 households equipped with these technologies. The author and his closest co-workers recommend equipping boilers, including both older and newer ones, with low-power electrostatic precipitators. In this way, one can burn low-quality fuels while keeping the emission of airborne dust at a low level. It is a quick and not pricey solution to the smog problem.
2
Content available Nonlinear phenomena in microturbine dynamics
EN
This paper presents the results of the analysis of the dynamic performance of a rotor that is a component of the ORC turbine set with the net electrical output of 100 kW and the nominal speed of 9000 rpm. This device is dedicated for municipal Local Energy Centres (LEC). The research was conducted using tools capable of performing the necessary simulation of the system operating under highly unstable conditions, i.e. in a strongly nonlinear regime. In this regard, the author of the paper followed the subsequent phases of whirl/whip formation manifested in the fluid film. Three constructional solutions within the scope of the bearing were examined with conventional and non-conventional lubricating mediums (mineral oils and low boiling mediums). An approach using rolling bearings was also considered. On the basis of those scientific studies, the decision to build a working prototype of the machine was taken. Such a prototype has already been manufactured, having regard to the outcome of the conducted analyses.
PL
Praca przedstawia wyniki badań dynamiki mikroturbin ORC o mocy elektrycznej 100 KW i prędkości nominalnej 9000 obr./min. Urządzenie to jest dedykowane dla lokalnych klastrów energii (LEC). Badania przeprowadzone zostały za pomocą narzędzi badawczych umożliwiających ocenę stanu maszyny w warunkach jej niestabilnej pracy, a więc w zakresie silnej nieliniowości. Autor pracy prześledził rozwój wirów i bicia olejowego powstających w filmie olejowym po przekroczeniu granicy stabilności. Przebadane zostały trzy warianty konstrukcyjne łożysk ze smarowaniem konwencjonalnym oraz niekonwencjonalnym (olej mineralny i czynniki niskowrzące). Rozważony został również przypadek łożysk tocznych. Na podstawie uzyskanych wyników wybrana została wersja łożyskowania zastosowana przy budowie prototypu maszyny.
EN
The paper presents the research results of the microturbines dynamics with power of a few to several hundred kW. These 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 Institute of the Fluid-Flow Machinery of the Polish Academy of Sciences in Gdańsk. 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.
PL
Jednym z problemów na etapie obecnych zastosowań wymienników ciepła jest zaprojektowanie możliwie jak najmniejszych ich konstrukcji. Objętość wymienników, to tylko jedno z podstawowych kryteriów efektywności urządzenia takiego jak mikrosiłownia domowa, czy skraplacz powietrznej pompy ciepła. W obiegach termodynamicznych pomp ciepła występują dwa podstawowe wymienniki, a są to parownik, w którym czynnik roboczy odparowuje pobierając ciepło, oraz skraplacz, w którym czynnik roboczy skraplając się podgrzewa wodę lub powietrze do ogrzewania pomieszczeń oraz celów użytkowych. W materiale podano algorytmy służące do wyznaczania parametrów mikro kanałowych parowników i skraplaczy.
EN
One of the most important challenges for designers of modern heat exchangers is reduction of their dimensions. The volume of a heat exchanger is very important parameter of household micro power plants and heat pumps. Thermodynamic cycles engage two main types heat exchangers – evaporators with boiling fluid absorbing heat and condensers where condensing medium gives useful heat to water or air. In the paper calculating methods for determination of parameters of micro channel evaporators and condensers are given.
PL
W artykule przedstawiono prosty model matematyczny wymiany ciepła oraz modyfikacji spadku ciśnienia w kanale, w którym uwzględniono modyfikację charakterystyki cieplno-przepływowej wymiennika na skutek zatykania się kanałów. Model porównano z własnymi danymi eksperymentalnymi prototypu wymiennika mikrokanałowego. Model ten jest szczególnie użyteczny w przypadku konieczności oceny pracy wymiennika, w którym występuje zagadnienie jego zatykania się, bez konieczności rozbierania takiego wymiennika. Jest to zatem nieniszcząca metoda wyznaczenia stopnia zatkania kanalików wymiennika.
EN
In the paper a simple mathematical model of heat transfer and flow resistance is given for heat exchangers with partially blocked channels. The predictions are compared with own experimental data for a prototype micro channel heat exchanger. Presented model is particularly useful for evaluation of a heat exchanger performance with partially blocked channels without its dismantling. Determination of the blockage degree is then possible with this model.
PL
Powietrzne pompy ciepła (PPC) w opinii inwestorów, pomimo że są zdecydowanie tańsze od ich odpowiedników z gruntowymi wymiennikami ciepła, nie cieszą się duża popularnością. Podstawowym celem projektu RenewX jest opracowanie i wykazanie pozytywnych cech technologii wymienników ciepła dla PPC przez osiągnięcie zwiększonej ich wydajności i zmniejszenie wymiarów parownika (jego bardziej zwarta konstrukcja) oraz możliwość równoległego wykorzystania dodatkowych źródeł energii w celu wspomagania powietrznej strony tego wymiennika za pomocą OZE.
EN
Air heat pumps are significantly cheaper than models with ground heat exchangers, but very often they are not preferred by investors. The main tasks of the RenewX project are design and demonstration of favorable characteristics of air heat pumps evaporators with higher capacity and smaller dimensions. The possibility of auxiliary use of renewable energy sources is also analysed .
EN
This paper presents examples of technologies for distributed energy generation developed at the The Szewalski Institute of Fluid Flow Machinery of the Polish Academy of Sciences in Gdańsk. These are combined heat and power (CHP) units (generating heat and electricity) for houses with a power from several to tens of kW and for municipalities in the form of the Municipal Energy Centres (with a capacity of several hundred kW up to several MW). A unique project, specializing in ‘energy-plus’ technologies for individual houses and other buildings, which aims to build a Research Centre of PAS in Jabłonna is also presented. These are key technologies for energy sector with respect to distributed generation. Additionally, the article discusses the conditions and opportunities for the development of civil energy generation in our country. Civic energy generation is a great vision in which the citizen becomes an entity and do not subject to the energy market, and additionally has its virtual advisor in the form of smart grid and data processing technologies in a ‘digital cloud’.
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.
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.
EN
The topic of the article is the analysis of the influence of selected design parameters and operating conditions on the radial steam micro-turbine, which was adapted to operate with low-boiling agent in the system based on the ORC. In the following parts of this article the results of the thermal load analysis, the residual unbalance and the stiffness of bearing supports are discussed. Studies showed that the steam micro-turbine is characterized by very good dynamic properties and is resistant to extreme operating conditions. The prototype of micro-turbine has passed a series of test calculations. It has been found that it can be subjected to experimental research in the micro combined heat and power system.
EN
The paper presents the results of experimental investigations of the ORC system with two scroll expanders which have been used as a source of electricity. The working fluid was HFE-7100 – a newly engineered fluid with a unique heat transfer and favourable environmental properties. In the ORC system three heat exchangers were used (evaporator, regenerator, condenser) and before expanders the droplet separator was installed. As a source of heat an innovative biomass boiler was used. Studies have been carried out for the expanders worked in series and in parallel. The paper presents the thermal and fluid-flow properties of the ORC installation for the selected flow rates and different temperatures of the working medium. The characteristics of output electrical power, operating speed and vibrations for scroll expanders were also presented.
14
Content available remote Obliczenia własności układu wirnikowego turbiny o mocy 100 kW
PL
Praca przedstawia wyniki badań symulacyjnych własności układu wirnikowego turbiny energetycznej z łożyskami ślizgowymi smarowanymi medium roboczym turbiny – siloksanem MDM. Opisywany problem dotyczy określenia temperatur i pośrednio lepkości czynnika smarującego łożyska. Połączono możliwości programu ANSYS (obliczenia pola temperatur w łożyskach) oraz własnego programu MESWIR (obliczenia charakterystyk kinetostatycznych i dynamicznych układu wirnikowego).
EN
The paper presents the results of computer simulations of the turbine properties. The bearings of the turbine are lubricated with the use of the working medium – siloxane MDM. The presented problem concerns the quantification of the lubricating fluid temperature inside the bearings. The temperature determines the viscosity of the lubricant. A field of temperature of the bearings was calculated with the use of ANSYS. The kinetostatic and dynamic properties of the rotor-bearings system are obtained with the own program MESWIR.
EN
This paper presents examples of technologies for distributed energy generation developed under the projects coordinated by the IFFM PAS in Gdańsk. These are CHP units (generating heat and electricity) for houses with a power from several to tens of kW and for municipalities in the form of the Municipal Energy Centers (with a capacity of several hundred kW up to several MW). A unique project, specializing in “energy-plus” technologies for residential houses and other buildings, which aims to build a Research Centre of PAS in Jabłonna is also presented,. These are key technologies for energy sector with respect to distributed generation. Additionally, the article discusses the conditions and opportunities for the development of energy generation or more broadly: civic energy generation in our country. Civic energy generation is a great vision in which the citizen becomes an entity and do not subject to the energy market, and additionally has its virtual advisor in the form of smart grid and data processing technologies in a “digital cloud”.
16
Content available remote New method of state analysis and diagnostics of power micro-devices
EN
In the small scale, turbines and bearings are a source of specific problems connected with securing stable rotor operation. Two kinds of high-speed micro-turbines of electric power of about 3 KW with multistage axial and radial rotors supported on foil bearings have been accepted. The scope of the present article is limited to the discussion of the dynamic characteristics of the selected design. The properties of the rotor combined with slide bearings (foil bearings in this particular case) were taken under investigation. Analysing the dynamic state of the domestic power plants requires qualitatively novel research tools. It turned out that the situation is possible that the rotor, after losing its stability, stabilises again when the rotational speed increases. This is a phenomenon determined by the author as "multiple whirls." Another topic discussed in this paper is an assessment of the influence of a random character of certain input data, in this case, changes of external excitations of the system. This problem is related to the "heuristic models" often placed in opposition to widely used algorithmic models.
PL
W pracy przedstawiony został przykład mikrosiłowni kogeneracyjnej możliwej do szerokiej aplikacji w tzw. mikrowytwarzaniu energii cieplnej i elektrycznej opartym na źródłach odnawialnych. Analizowanym urządzeniem jest wysokoobrotowa mikroturbina o mocy zaledwie kilku KW. Celem pracy nie są jednakże szczegóły konstrukcyjne tak zdefiniowanych urządzeń, lecz nowe metody analizy stanu dynamicznego i pozyskiwania relacji diagnostycznych. Jak się okazało, te małe urządzenia o prędkościach obrotowych wirnika od kilkudziesięciu do kilkuset tysięcy obrotów na minutę stanowią prawdziwe wyzwanie dla badaczy i eksploatatorów. Wiele tradycyjnych pojęć i metod badawczych, z powodzeniem stosowanych w maszynach większych, musiało zostać zweryfikowanych. Przy tak wysokich prędkościach obrotowych układ może przekraczać granicę stabilnej pracy wielokrotnie i dalej bezawaryjnie pracować, może też samoczynnie się stabilizować w wysokich zakresach prędkości. Mamy tu do czynienia z nowym zjawiskiem „wirów wielokrotnych" o zupełnie innych, nieznanych dotąd w eksploatacji symptomach diagnostycznych. W pracy zaproponowany też został inny sposób matematycznego opisu stanu maszyny oparty na metodach heurystycznych. Opis heurystyczny jest przeciwieństwem opisu algorytmicznego i uwzględnia m.in. przypadkowe błędy danych czy autokorekcję modelu w trakcie obliczeń. Opis heurystyczny jest bliższy naturze człowieka i warto go szerzej rozpropagować w budowie i eksploatacji maszyn. Czy przyjmie się w praktyce? W pracy podane zostały przykładowe wyniki obliczeń oparte na nowym podejściu odnoszące się do małych urządzeń energetycznych. To pierwszy krok na tej drodze w badaniach prowadzonych w ośrodku gdańskim i olsztyńskim.
PL
W artykule omówiono wyniki badań symulacyjnych małogabarytowego wirnika mikroturbiny osiowej łożyskowanego ślizgowo oraz tocznie. Obiektem badań był układ wirujący mikroturbiny zaprojektowanej dla powstającej w IMP PAN w Gdańsku mikrosiłowni kogeneracyjnej małej mocy, pracującej w obiegu ORC. Prezentowane badania zostały wykonane przy wykorzystaniu własnych programów serii MESWIR oraz programów komercyjnych: MADYN 2000 i ABAQUS. W artykule omówiono wyniki analizy modalnej małogabarytowego wirnika z uwzględnieniem właściwości sprężysto-tłumiących łożysk oraz przedstawiono wyniki analizy drgań wymuszonych wirnika łożyskowanego ślizgowo oraz tocznie. Wyniki badań zostaną wykorzystane podczas opracowywania i optymalizacji ostatecznego rozwiązania konstrukcyjnego mikroturbiny.
EN
This article presents the results of investigations of dynamic characteristics of a small-dimension rotor with slide and rolling element bearings. The object of investigations was the rotor-bearing system of the low-power steam microturbine designed in the IF-FM PASci, Gdansk. The investigations were performed using own codes MESWIR series and commercial FEA software MADYN 2000 and ABAQUS. The results of modal analysis for micro-rotor supported on slide and rolling element bearing were showed and discussed. Forced vibration analysis of the rotor-bearing system was also performed. The results of investigations will be used in further stages of the design and optimization of the microturbine.
18
Content available remote New method of analysis of dynamic state of power micro-devices
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.
20
Content available remote Instability and heuristic problems in high - speed rotor of a micro turbine
EN
Nonlinear forms of vibrations in rotors dynamics, especially after exceeding the stability limit, as well as the assessment of not precise and randomly variable input parameters, still constitute the research subject in many institutions all over the world. The results of investigations of the high-speed rotor of a micro turbine, being an element of the micro power plant in dispersed power engineering based on renewable energy sources - are presented in the paper. The basic problem of such devices is to assure a stable rotor operation within the entire range of rotational speeds. Foil bearings and special rotor structure were applied. It turned out that the situation in that the rotor - after loosing its stability - stabilises again when the rotational speed increases, is possible. This is a new phenomenon determined by the author as 'multiple whirls'. Possibilities of stabilizing the situation by the application of hybrid lubrication and siphon pockets are also presented in the paper. Another topic, discussed in the hereby paper, is an assessment of the influence of a random character of certain input data - in this case - changes of external excitations of the system. This problem is related to the so-called heuristic models often placed in opposition to widely used algorithmic models. The obtained results indicate different influence of disturbances depending on the system working conditions. After exceeding the stability limit, it means in a highly nonlinear operation range, the influence of disturbances significantly decreases. It is rather unexpected result. Research tools such as computer series codes and the method of their experimental verification are also included in the paper.
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