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    Wyświetlanie 1-6 z 6
    Tytuł:
    Modelling of vane and rotor blade rows in simulations of gas turbine performance
    Autorzy:
    Sznajder, Janusz
    Powiązania:
    https://bibliotekanauki.pl/articles/244955.pdf
    Data publikacji:
    2019
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    aircraft engines
    mechanical engineering
    engine parts
    simulation
    modelling
    Opis:
    A method of modelling of nozzle and rotor blade rows of gas turbine dedicated to simulations of gas turbine performance is proposed. The method is applicable especially in early design stage when many of geometric parameters are yet subject to change. The method is based on analytical formulas derived from considerations of flow theory and from cascade experiments. It involves determination of parameters of gas flow on the mean radius of blade rows. The blade row gas exit angle, determined in turbine design point is a basis for determination of details of blade contour behind the throat position. Throat area is then fixed based on required maximum mass flow in critical conditions. Blade leading edge radius is determined based on flow inlet angle to the blade row in the design point. The accuracy of analytical formulas applied for definition of blade contour details for assumed gas exit angle was verified by comparing the results of analytical formulas with CFD simulations for an airfoil cascade. Losses of enthalpy due to non-isentropic gas flow are evaluated using the analytical model of Craig and Cox, based on cascade experiments. Effects of blade cooling flows on losses of total pressure of the gas are determined based on analytical formulas applicable to film cooling with cooling streams blowing from discrete point along blade surface, including leading and trailing edges. The losses of total pressure due to film cooling of blades are incorporated into the Craig and Cox model as additional factor modifying gas flow velocities.
    Źródło:
    Journal of KONES; 2019, 26, 1; 183-190
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Simulations of hot-gas flow in internally cooled cascade of turbine vanes
    Autorzy:
    Sznajder, Janusz
    Powiązania:
    https://bibliotekanauki.pl/articles/242679.pdf
    Data publikacji:
    2019
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    aircraft engines
    mechanical engineering
    engine parts
    simulation and modelling
    Opis:
    An experiment in cooling of gas turbine nozzle guide vanes was modelled numerically with a conjugate viscousflow and solid-material heat conduction solver. The nozzle vanes were arranged in a cascade and operated in highpressure, hot-temperature conditions, typical for first turbine stage in a flow of controlled-intensity, artificiallygenerated turbulence. The vane cooling was internal, accomplished by 10 channels in each vane with cooling-air flow. Numerical simulations of the experiment were conducted applying two turbulence models of the k-omega family: k-omega-SST and Transition SST implemented in the ANSYS Fluent solver. Boundary conditions for the simulations were set based on conditions of experiment: total pressures and total temperature on inlet to cascade, static pressure on the outlet of the cascade and heat flux on the surface of cooling channels. The values of heat flux on the surface of cooling channels were evaluated based on Nusselt numbers obtained from experiment and varied in time until steadystate conditions were obtained. Two test cases, one with subcritical outlet flow, and another one, with supercritical outlet flow were simulated. The result of experiment – distributions of pressure, surface temperature, and heat transfer coefficients on the vane external surface were compared to results of numerical simulations. Sensitivity of the vane surface temperatures and heat transfer coefficients to turbulence models and to boundary-condition values of parameters of turbulence models: turbulence energy and specific dissipation of turbulence energy was also studied.
    Źródło:
    Journal of KONES; 2019, 26, 2; 151-158
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of the application of distributed propulsion to the AOS H2 motor glider
    Autorzy:
    Kuźniar, Michał
    Orkisz, Marek
    Powiązania:
    https://bibliotekanauki.pl/articles/244774.pdf
    Data publikacji:
    2019
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    aircraft engineering
    engines
    mechanical engineering
    Opis:
    The paper describes the selection of a distributed propulsion for the AOS H2 motor glider (selection of engines, their number, and propellers) and determination of its performance. This analysis is related to the research conducted on environment friendly and hybrid propulsions in various research centres. The main aim of the analyses conducted is to increase the performance of vehicles powered by electric motors. The batteries have a low density of energy, i.e. the ratio of mass to cumulated energy. Instead of a battery set, it is possible to apply a hybrid- electric system, where the combustion engine works as a generator or an electric-hydrogen generator, where the hydrogen cell supports a small set of batteries. One of such flying vehicles, fitting in this trend, is the AOS H2 motor glider built at the Rzeszow University of Technology in cooperation with other universities. It is a hybrid aircraft, equipped with a hydrogen cell, which together with a set of batteries is a source of electricity for the Emrax 268 electric motor. To increase the vehicle's performance (the range and flight duration), it is possible to use a distributed propulsion. This type of propulsion consists in placing many electric motors along the wingspan of the aircraft. Appropriate design of such a system (propeller diameters, engine power, number of engines) can improve the aerodynamic and performance parameters of the airframe. An analysis of the performance for the selected flight trajectory for this propulsion variant was conducted and compared to the performance of the AOS H2 motor glider equipped with traditional propulsion. The consumption of hydrogen was also determined for both systems. The results obtained were presented in the diagrams and discussed in the conclusions.
    Źródło:
    Journal of KONES; 2019, 26, 2; 85-92
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Analysis of applicability of thermography to assess health of gas turbine blades
    Autorzy:
    Kułaszka, A.
    Błachnio, J.
    Powiązania:
    https://bibliotekanauki.pl/articles/246976.pdf
    Data publikacji:
    2013
    Wydawca:
    Instytut Techniczny Wojsk Lotniczych
    Tematy:
    engines
    aircraft engineering
    mechanical engineering
    Opis:
    A gas turbine is one of the most heavily loaded, both mechanically and thermally, structural components of an aircraft turbine engine. Hence, the most common reasons for failure are overheating and thermal fatigue of the blade material. It is of great significance for the safety of aeronautical systems that service is monitored; this is carried out to verify the health of these items using all available diagnostic methods. The primary aim is to detect and identify, as early as possible, any probable hazards to the engine. The preliminary assessment of the gas turbine blades condition is carried out via a visual inspection e.g. using a video borescope. During any repair, the preliminary assessment is conducted with a visual method, which is followed with some other non-destructive inspection techniques, e.g. flaw detection, intended to provide full colour images. The essential assessment of the blade condition consists in metallographic examination which precludes further operational use of the item. Probable errors in this assessment usually result in considerable cost of unnecessary repairs of the entire engine. Presented in the paper is the pulse thermography technique being a new NDT method, which is capable of diagnosing changes in the blade condition and to detect early stages of damages to turbine blades. Results of inspections of the blades subjected to high temperature and corresponding changes in signals of thermal response of the blade material stimulated with a heat pulse have also been given. Effects of the testing work have been used to detect changes, against temperature, in thermophysical properties of super alloy used in gas turbine blades. The results have been successfully verified using metallographic examination. To conclude: the thermographic method provides good reliability of the assessment of changes in the microstructure of the blade.
    Źródło:
    Journal of KONES; 2013, 20, 2; 237-244
    1231-4005
    2354-0133
    Pojawia się w:
    Journal of KONES
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Areas of Investigation into Air Intake Systems for the Impact on Compressor Performance Stability in Aircraft Turbine Engines
    Autorzy:
    Kozakiewicz, Adam
    Adamczyk, Maciej
    Wróblewski, Mirosław
    Powiązania:
    https://bibliotekanauki.pl/articles/2067549.pdf
    Data publikacji:
    2022
    Wydawca:
    Stowarzyszenie Inżynierów i Techników Mechaników Polskich
    Tematy:
    mechanical engineering
    aviation
    aircraft engines
    compressor stall
    compressors
    Opis:
    The high demands placed on aircraft turbine engines necessitate the use of the latest engine compressors which must be increasingly efficient and more robust due to the increased loads. The key safety issue in this context is to ensure compressor stability over all engine speed ranges and aircraft flight regimes. This paper presents selected areas of research into surge and stall of axial compressors used in aircraft turbine engines based on scientific publications in recent years. On the basis of the analysed literature the authors defined the main research areas into compressor surge, namely: air intake research, compressor research and combined air intake and compressor system research. On the background of the conducted analysis the authors has presented their own areas of research. The aim of this work is to search for an intake-compressor design more passively resistant to stall or surge phenomena without necessity of implementation of complex control systems to prevent compressor stall.
    Źródło:
    Advances in Science and Technology. Research Journal; 2022, 16, 1; 62--74
    2299-8624
    Pojawia się w:
    Advances in Science and Technology. Research Journal
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
    Tytuł:
    Determination of Ranges of Unstable Operation of Axial Compressor for Aircraft Turbine Engines
    Wyznaczanie zakresów niestatecznej pracy sprężarki osiowej lotniczych silników turbinowych
    Autorzy:
    Kozakiewicz, Adam
    Adamczyk, Maciej
    Majcher, Maciej
    Powiązania:
    https://bibliotekanauki.pl/articles/2073829.pdf
    Data publikacji:
    2022
    Wydawca:
    Wojskowa Akademia Techniczna im. Jarosława Dąbrowskiego
    Tematy:
    mechanical engineering
    aviation
    aircraft engines
    stall
    compressor
    inżynieria mechaniczna
    lotnictwo
    silniki lotnicze
    pompaż
    sprężarki
    Opis:
    Currently, strict requirements are set for aircraft turbine engine performance, which requires introducing larger, more complex, and more loaded compressors. In sub-assemblies designed in this manner, a vital challenge is to maintain stable compressor operation across wide range of operating conditions. This article presents the results of analysis and estimation of the range of unstable operation of an example axial compressor for a turbofan jet engine with high mass flow ratio. The analyses and numerical simulations performed made it possible to estimate the limit performance for compressor operation for two particularly important phases of flight.
    Współcześnie stawia się wysokie wymagania wobec parametrów osiąganych przez lotnicze silniku turbinowe, co powoduje konieczność wprowadzania do konstrukcji coraz większych, bardziej skomplikowanych i obciążonych sprężarek. W tak projektowanych podzespołach istotnym wyzwaniem jest zachowanie stabilności pracy sprężarki w szerokim zakresie warunków operacyjnych. W niniejszym artykule przedstawiono wyniki analizy i oszacowania zakresu niestatecznej pracy przykładowej sprężarki osiowej do dwuprzepływowego silnika turbinowego o dużym stopniu podziału masowego natężenia przepływu. Przeprowadzone analizy i obliczenia pozwoliły na oszacowanie granicznych parametrów pracy sprężarki dla dwóch szczególnie istotnych faz lotu samolotu.
    Źródło:
    Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa; 2022, 13, 1 (47); 45--56
    2081-5891
    Pojawia się w:
    Problemy Mechatroniki : uzbrojenie, lotnictwo, inżynieria bezpieczeństwa
    Dostawca treści:
    Biblioteka Nauki
    Artykuł
      Wyświetlanie 1-6 z 6

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