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EN
In this paper the LNG carrier with steam turbine propulsion plant maintenance records has been analysed. Actual observed data from the ship, built in 2001, are from ship maintenance history data from September 2002 until August 2010. During the analysed period, main propulsion turbine had one major failure and several minor failures. The ship had three dry docks and one was prolonged due to increased requirements for cargo transport. Total running hours of the main propulsion turbine in the observed period of time were 63204 hours. The list of failures and influence of each mentioned failure of main turbine propulsion machinery is discussed and analysed in respect to the propulsion autonomy of the vessel.
EN
This paper presents the results of analysis of steam turbine start-up using Thermal-FSI (Thermal-Fluid-Structure-Interaction). Reference and acceleration start simulations were carried out. Attention focused on a steam unit as they account for most electricity generation in Poland. Accelerated start-up is of interest as a possible method for reducing the adverse impact of renewable energy by controlling the injection of cooling steam, set against the backdrop of increasing RES and their negative impact on the operation of steam units. The work is the result of research into the possibility of accelerating the start-up of a steam turbine.
PL
W artykule przedstawiono różne warianty modernizacji części przepływowej turbin parowych znajdujących się w wieloletniej eksploatacji. Maksymalny przyrost mocy może być uzyskany drogą modernizacji układu łopatkowego. Przejście do łopatek ze zmienianym kątem wypływu α1, zastosowanie tzw. meridionalnego profilowania krótkich łopatek pierwszych stopni części wysokoprężnej pozwala zwiększyć sprawność o około 2÷3% w porównaniu ze stanem wyjściowym konstrukcji. Pewne rezerwy podwyższenia ekonomiczności związane są także z modernizacją uszczelnień. Współczesne rozwiązania konstrukcyjne uszczelnień umożliwiają zmniejszenie przecieków pary o około 10÷30%, co prowadzi do wzrostu sprawności turbiny. Maksymalna efektywność aerodynamiczna elementów części przepływowej z dodatnimi wartościami wzdłużnego gradientu ciśnienia jest osiągana w warunkach stabilnego przepływu bez oderwania warstwy przyściennej od ścianek. Dotyczy to zarówno dyfuzorowych wylotów korpusów wysokiego, średniego i niskiego ciśnienia jak i dyfuzorów zaworów regulacyjnych. Przeprowadzone badania i doświadczenia modernizacji wskazują na możliwość podwyższenia mocy turbozespołu do 10÷12% w odniesieniu do stanu początkowego. Taki rezultat osiągany jest kosztem modernizacji tylko samego układu łopatkowego bez zmiany detali korpusu a rozważane w pracy techniczne rozwiązania mogą być zastosowane podczas kapitalnego remontu turbiny parowej nawet, w warunkach elektrowni.
EN
Different designs of modification of flow range in long-lived turbine plants have been considered in the presented paper. The maximum turbine power increment can be achieved by modernization of a turbine blading system. The use of blades with various nozzle-exit angles and meridional profiling for short blades of the first stages in high-pressure section provides an opportunity to increase efficiency by 2÷3% in comparison with a reference power. A significant gain in performance is associated with the design improvement of seals. Modern designs of seals make it possible to decrease steam leakage by 10÷30% that results in an increase in turbine efficiency. Maximum aerodynamic efficiency of flow channels with adverse pressure gradient has been achieved under a stable unseparated flow. The same holds for diffuser steam-turbine exhausts of the HP (high-pressure) part, the LP (low-pressure) part and the IP (intermediate pressure) part, and also diffusers of control valves. The research and the first effort of research in modification suggest possible increment of a turbine power up to 10÷12% in comparison with a reference power. This result can be obtained only due to modification of the blade system without changing the component of a turbine casing. The discussed engineering proposals can be implemented major overhaul of the steam turbine even in power plant conditions.
EN
Due to the development of alternative propulsion systems, there is a need for LNG tanker turbine propulsion plants to regain their competitiveness. Previous research revealed effective methods to increase the thermal efficiency of the steam cycle based on quality assessment, and it was proposed that the latent heat of the main turbine exhaust steam could be recovered. Research was carried out for the steam cycle using regenerative heat exchangers fed by steam jet injectors. In this paper, an algorithm to determine the operating parameters of steam jet injectors, and the calculation results for different drive steam parameters are presented. The obtained results will be used as input parameters for further heat balance calculations of the proposed regenerative steam cycles.
PL
W artykule omówiono współcześnie obowiązujące zasady poprawności instalacji czujników umożliwiające realizację jakościowo możliwie najlepszych pomiarów dla sygnałów pozyskiwanych z tych czujników. W przypadku licznych turbozespołów pracujących w kraju (łącznie z tymi najnowszymi) opisane w artykule zasady są mniej lub bardziej naruszone.
EN
Steel castings are often used in the construction of valve chambers of steam turbines. Stringent requirements are set due to the continuous operation of the material at elevated temperatures, in the order of 300ºC to 600ºC. The material of the valve chamber must be resistant to fatigue-creep changes as well as corrosion. This material must be also resistant to dynamic damage which occures when the turbine is starting and stopping. Dynamic damage is induced by a short-lasting but intense accumulation of localized stresses. The castings of the valve chambers of the steam turbine are usually made from the “three-component” type CrMoV-cast steel. Mentioned castings of the valve chamber are continuously subjected to high temperatures, either constant and periodically variable stresses. Due to this, the degradation process of material of the castings is taking place. It is caused by physicochemical processes such as: creep, relaxation, thermal fatigue, corrosion, erosion and changes in material properties, e.g. displacement of the critical point of brittleness. Finally, first cracks and deformations can be observed in the material during the operation. The art presents the process of revitalization technology of the steam turbine valve chamber which was subjected to long-term operation at high temperatures. The revitalization process is aimed at improving the plastic properties of the material and, as the result, extending its service life. The research presented in the article show that impact strength of the chamber material after revitalization is very high. Also the strength properties of the valve chamber, after revitalization, are high and in line with the requirements. The study show that the revitalization of the valve chamber was carried out correctly and restored the material to plastic deformation.
EN
The process of the design of the 1 MW steam turbine includes designing the stator and rotor blades, the steam turbine inlet and exit, the casing and the rotor. A turbine that operates at rotation speeds other than 3000 rpm requires a gearbox and generator with complex electronic software. This article analyses the efficiency of eight turbine variants, including seven inlet geometries and three stages of stator as well as an eight variant with one of the inlets, all three stages and an outlet. This article analyses the efficiency of 8 turbine variants, including four spiral inlet geometries and tree stages in a 1 MW steam turbine. In the article, inlets and 1st stator blades of various geometries were analysed to obtain maximal turbine efficiency. Changing the inlet spiral from one pipe to two pipes increased the turbine efficiency. The geometry of the blades and turbine inlets and outlet was carried out using Design Modeller. The blade mesh was prepared in TurboGrid and inlet in ANSYS Meshing.
EN
The article presents the results of the study on the possibilities of repair by welding methods of exploitation steam turbine bodies. Two hull were investigation after a lifetime of more than 200.000 hours. Repair welding study were carried out on the L17HMF cast steel body in the immediately after exploitation condition, whereas the L21HMF cast steel body underwent a revitalization after the exploitation, and then the welding repair research were performed. On the material taken from the L17HMF cast steel hull, welding repairs were made by welding the previously cut four grooves measuring 200 mm 50 mm 50 mm, which were simulations of material defected. All samples were made in areas where maximum steam temperatures were operating. Welds were tested with destructive and non-destructive methods to determine their quality and define non-compliances detected. The L21HMF cast steel was subjected to a revitalization process, which consisted the hull in subjecting heat treatment in order to obtain favourable structural changes and improve the strength properties. Non-destructive examinations and hardness tests were carried out on the remedial weld, indicating the required quality of repairing remedial weld. Comparative study is aimed at demonstrating the main welding problems during the repair welding of exploitation steam turbine hulls.
9
Content available remote The possibility of extending the life of cast steel hulls of the steam turbine
EN
The paper presents the analyze the lifetime of the HP steam turbine hull for the EC Gdynia TG1 combined heat and power plant as part of the renovation. The impact of exploitation on changes in mechanical properties of the steam turbine hulls was determined. At the preliminary material tests were carried out, qualifying the hull of the steam turbine to undertake the revitalization process. Then, after non-destructive testing, trepanation samples were taken from the cold zone and the hot hull, which were subjected to mechanical properties tests. The next stage of work was the revitalization process including hardening and tempering. The mechanical properties and metallographic were carried out testing. In the next stage of work, non-destructive testing was performed to detect cracks and a decision was made to repair these areas by welding. The last stage of the work includes an analysis of the vitality of the steam turbine hull after revitalization.
PL
W pracy przedstawiono analizę żywotności kadłuba turbiny parowej WP w elektrociepłowni EC Gdynia TG1 w ramach remontu. Określono wpływ eksploatacji na zmiany własności mechaniczne metalu kadłubów turbiny parowej. Przeprowadzono wstępne testy materiałowe, kwalifikujące kadłub turbiny parowej do podjęcia procesu rewitalizacji. Następnie po badaniach nieniszczących pobrano próbki trepanacyjne ze strefy zimnej i gorącej kadłuba, które poddano badaniom mechanicznym. Kolejnym etapem pracy był proces rewitalizacji, w tym hartowanie i odpuszczanie. Następnie przeprowadzono badania metalograficzne i wytrzymałościowe, a w dalszej kolejności badania nieniszczące w celu wykrycia pęknięć i podjęto decyzję o naprawie tych obszarów przez spawanie. Ostatni etap prac obejmuje analizę żywotności kadłuba turbiny parowej po rewitalizacji.
EN
The paper presents the results of experimental tests and numerical simulations related with the strength differential effect. Tensile and compression tests on 2CrMoV low-alloy steel are performed to evaluate the magnitude of the yield stress difference in tension and compression. The strength differential parameter is then used in the formula for equivalent stress proposed by Burzyński. The material effort calculated using Burzyński and Huber-Mises-Hencky hypotheses was compared for different start-stop cycles. Analytical notch stress-strain correction rules by Neuber and Glinka-Molski were applied to compute elastic-plastic strain amplitudes in rotor circumferential grooves. It was finally shown that the strength differential effect has significant influence on the predicted fatigue life under thermo-mechanical loading.
EN
Consumption of energy is one of the important indicators in developing countries, but a lot of companies from the energy sector have to cope with three key challenges, namely how to reduce their impact on the environment, how to ensure the low cost of the energy production and how to improve the system overall performance? For Polish energy market, the number of challenges is greater. The growing demand for electricity and contemporary development of nuclear power technology allow today’s design, implement new solutions for high energy conversion system low unit cost for energy and fuel production. In the present paper, numerical analysis of modular high-temperature nuclear reactor coupled with the steam cycle for electricity production has been presented. The analysed system consists of three independent cycles. The first two are high-temperature nuclear reactor cycles which are equipped with two high-temperature nuclear reactors, heat exchangers, blowers, steam generators. The third cycle is a Rankine cycle which is equipped with up to four steam turbines, that operate in the heat recovery system. The analysis of such a system shows that is possible to achieve significantly greater efficiency than offered by traditional nuclear reactor technology.
EN
This paper presents the origins of marine steam turbine application on liquefied natural gas carriers. An analysis of alternative propulsion plant trends has been made. The more efficient ones with marine diesel engines gradually began to replace the less efficient plants. However, because of many advantages of the steam turbine, further development research is in progress in order to achieve comparable thermal efficiency. Research has been carried out in order to achieve higher thermal efficiency throughout increasing operational parameters of superheated steam before the turbine unit; improving its efficiency to bring it nearer to the ideal Carnot cycle by applying a reheating system of steam and multi stage regenerative boiler feed water heating. Furthermore, heat losses of the system are reduced by: improving the design of turbine blades, application of turbine casing and bearing cooling, as well as reduction in steam flow resistance in pipe work and maneuvering valves. The article identifies waste energy sources using the energy balance of a steam turbine propulsion plant applied on the liquefied natural gas carrier which was made out basing on results of a passive operation experiment, using the measured and calculated values from behavioral equations for the zero-dimensional model. Thermodynamic functions of state of waste heat fluxes have been identified in terms of their capability to be converted into usable energy fluxes. Thus, new ways of increasing the efficiency of energy conversion of a steam turbine propulsion plant have been addressed.
EN
Turbine stages can be divided into two types: impulse stages and reaction stages. The advantages of one type over the second one are generally known based on the basic physics of turbine stage. In this paper these differences between mentioned two types of turbines were indicated on the example of single stage turbines dedicated to work in organic Rankine cycle (ORC) power systems. The turbines for two ORC cases were analysed: the plant generating up to 30 kW and up to 300 kW of net electric power, respectively. Mentioned ORC systems operate with different working fluids: DMC (dimethyl carbonate) for the 30 kW power plant and MM (hexamethyldisiloxane) for the 300 kW power plant. The turbines were compared according to three major issues: thermodynamic and aerodynamic performance, mechanical and manufacturing aspects. The analysis was performed by means of the 0D turbomachinery theory and 3D computational aerodynamic calculations. As a result of this analysis, the paper indicates conclusions which type of turbine is a recommended choice to use in ORC systems taking into account the features of these systems.
PL
W artykule przedstawiono wyniki analiz dotyczących sprawności różnych układów napędowych stosowanych na współczesnych zbiornikowcach LNG. Omówiono wyniki identyfikacji oraz oceny jakościowej źródeł energii odpadowej konwencjonalnego turbinowego układu napędowego (CST). W artykule przeanalizowano możliwości zastosowania inżektora parowego w celu odzysku ciepła utajonego. Na podstawie uzyskanych wyników obliczeń inżektora przeprowadzono bilans energetyczny prostego układu realizującego obieg Clausiusa-Rankine’a z regeneracyjnym podgrzewaniem wody zasilającej. Wyznaczono stopień regeneracji układu w wyniku zastosowania inżektora parowego. Na podstawie otrzymanych wyników wyznaczono dalsze kierunki badań dla złożonych układów z wykorzystaniem inżektorów parowych.
EN
This paper presents the results of carried out analyses regarding efficiency and criteria evaluation of various propulsion plants of modern LNG (Liquid Natural Gas) carriers as well as identification and quality assessment of waste heat energy fluxes of a CST (Conventional Steam Turbine) plant. The possibility of use a steam jet injector in order to recover the latent heat is analysed. Calculations were carried out for an injector. On the basis of the results of the injector calculation, the heat balance of a simple regenerative Clausius- Rankine steam cycle was carried out. The degree of regeneration for cycle using the regenerative injector was determined. Based on results the further research directions for complex plants using a steam jet injector are indicated.
PL
W artykule przedstawiona została próba stworzenia wstępnego modelu klasyfikatora rozmytego użytecznego we wstępnym doborze profili łopatkowych turbin parowych. Dobór odpowiedniego rozwiązania dokonywany jest na podstawie parametrów przepływu czynnika przez wieńce turbiny. Tego typu narzędzie decyzyjne może okazać się przydatne zarówno w przypadku modernizacji istniejącego już obiektu, w którym zdiagnozowane uszkodzenia wymuszają kapitalny remont układu przepływowego, jak i przy projekcie nowego urządzenia.
EN
The article presents an attempt to create a preliminary fuzzy classifier model in the preliminary selection of steam turbines blade profiles. The selection of the appropriate solution is made on the basis of the parameters of the flow of the medium through the turbine rims. This type of decisionmaking tool may prove useful both in the case of the modernization of anexisting facility, in which the diagnosed faults force a complete overhaul of the flow system as well as the design of a new device.
EN
This paper presents optimization of selected combined diesel engine-steam turbine systems. Two systems: the system combined with waste heat one-pressure boiler only and its version containing additionally low-pressure boiler proper feeding degasifier and the system of two-pressure cycle, were taken into considerations. Their surplus values of power output and efficiency associated with utilization of waste heat contained in piston engine exhaust gas were compared to each other. For the considerations two high-power low-speed engines were taken into account. The main engines of comparable power of about 54 MW produced by Wartsila and MAN Diesel & Turbo firms, were selected.
EN
This paper presents a comparative analysis of thermodynamic cycles of two ship power plant systems with a hightemperature helium- cooled nuclear reactor. The first of them is a gas system with recuperator , in which classical gas chamber is substituted for a HTGR reactor (High Temperature Gas-cooled Reactor) . The second of the considered cycles is a combined gas-steam system where working medium flux from gas turbine outlet is directed into waste heat boiler and its heat is utilized for production of superheated steam to drive steam turbine. Preliminary calculations of the combine cycles showed that it is necessary to expand the system by adding to its steam part an inter-stage overheat for secondary steam, owing to that a required degree of steam dryness at outlet from the turbine can be reached, ensuring its correct operational conditions. The analyzed power systems were compared to each other with regard to efficiency of their thermodynamic cycles. Also, efficiency of particular cycles were subjected to optimization in respect to such parameters as : working gas temperature at outlet from reactor in gas system as well as steam pressure at outlet from waste heat boiler and partition pressure in steam part of combined system. Advantages of nuclear power plants compared with the classical power systems dominating currently in sea transport were also discussed.
18
Content available remote Efficiency optimisation of blade shape in steam and ORC turbines
EN
This paper is devoted to direct constrained optimisation of blading systems of large power and small power turbines so as to increase their internal efficiency. The optimisation is carried out using hybrid stochastic-deterministic methods such as a combination of a direct search method of Hooke-Jeeves and simulated annealing or a combination of a bat algorithm and simplex method of Nelder-Mead. Among free shape parameters are blade number and stagger angle, stacking blade line parameters and blade section (profile) parameters. One practical example of efficiency optimisation of turbine blading systems is modification of low load profiles PLK-R2 for high pressure (HP) stages of large power steam turbines. Another optimised geometry is that of an ORC radial-axial cogeneration turbine of 50 kWe. Up to 1% efficiency increase can easily be obtained from optimization of HP blade profiles, especially by making the rotor blade more aft-loaded and reducing the intensity of endwall flows. Almost 2% efficiency rise was obtained for the optimized 50 kWe ORC turbine due to flow improvement at the suction side of the blade.
19
Content available remote Wpływ procesu instalacji turbozespołu na zmiany przemieszczeń jego fundamentu
PL
Fundamenty pod maszyny charakteryzują się znacznymi ograniczeniami dopuszczalnych różnic przemieszczeń. W artykule przedstawiono zagadnienia dotyczące analizy warunków użytkowalności fundamentu turbozespołów, bazując na wynikach modelowania numerycznego. Wyniki analiz wskazują na zauważalny wpływ procesu etapowania instalacji poszczególnych elementów na rozwój przemieszczeń wywołanych zmianą schematu obciążenia.
EN
The foundations for machines are characterized by strict limitations on differential settlements. The problem of serviceability analysis for steam turbine foundation, based on numerical modeling results, is presented. It is shown that incremental loading due to installation process has a noticeable impact on displacement evolution.
EN
The paper presents a new method of lifetime calculations of steam turbine components operating at high temperatures. Component life is assessed on the basis of creep-fatigue damage calculated using long-term operating data covering the whole operating period instead of representative events only. The data are analysed automatically by a dedicated computer program developed to handle big amount of process data. Lifetime calculations are based on temperature and stress analyses performed by means of finite element method and using automatically generated input files with thermal and mechanical boundary conditions. The advanced lifetime assessment method is illustrated by an example of lifetime calculations of a steam turbine rotor.
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