BazTech - Yadda

1

The hybrid concept of turboshaft engine working according to Humphrey cycle dedicated to variety power demand - CFD analysis

Tarnawski Piotr

Combustion Engines

|

2023

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R. 62, nr 2

129--136

EN

The paper presents a new concept of the turbine engine in the area of pressure gain combustion (PGE). The engine works according to Humphrey’s cycle. Minor modification in construction has allowed power generation of 500 kW, 700 kW, 1000 kW, and 1800 kW. The concept successfully resolved the challenges related to the temporary opening and closing of the combustion chamber. The presented valve timing system has ensured effective gas flow and what stands behind it, an effective process of conversion of a high-pressure gas impulse into mechanical energy. Rotating combustion chambers enabled the application of an effective sealing system. The concept characterizes simple construction and potentially low power-to-weight coefficient. The CFD numerical analysis of the presented engine concept showed very promising effective efficiency and low specific fuel consumption.

2

„Above the Pack” diffusion aluminizing of turbine compressor blades made of EI867 in the aerospace industry

Pytel Anna, Nowotnik Andrzej, Nalborczyk-Kazanecka Agnieszka

Advances in Mechanical and Materials Engineering

|

2023

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Vol. 40, nr 1

171-179

EN

In the publication, tests were conducted on compressor turbine working blades made of EI-867 material, in accordance with the TU 14-1-402-72 standard, which were subjected to the gas non-contact aluminizing process. Metallographic analyses of the produced aluminide layer were undertaken, and the phase components of the aluminide layer microstructure were identified. This identification was achieved by analyzing the chemical composition in micro-areas using the EDS attachment in a scanning electron microscope and using X-ray diffraction. Additionally, hardness and creep resistance tests of the blades, after undergoing solution and aging processes, were performed over different durations. The research was aimed at exploring the feasibility of the aluminizing process using the "above the pack" method on parts made of EI-867 material and understanding the process's impact on the creep resistance of the part. Experimental research have shown that aluminizing turbine blades with EI-867 using the "above the pack" method to obtain a layer thickness in the range of 0.03-0.06 mm is possible within 10 hours at 950ºC. Aluminizing with the analyzed method results in the formation of an aluminized layer with a three-phase structure that ensures the appropriate strength of the coating. However, it has been shown that the aluminizing process using the "above the pack" method with the applied time of 10 hours causes a significant reduction in the creep resistance of the material. Based on the obtained results, it was shown that the non-contact aluminizing method for turbine blades made of EI 867 material does not meet aviation requirements for safe operation due to a significant reduction in mechanical properties.

PL

W pracy przeprowadzono badania łopatek roboczych turbiny sprężarki wytwarzanych z materiału EI-867 wg normy TU 14-1-402-72 poddawanych procesowi gazowego bezkontaktowego procesu aluminiowania. Wykonano badania metalograficzne wytworzonej warstwy aluminiowanej oraz poddano identyfikacji składniki fazowe mikrostruktury warstwy aluminidkowej za pomocą analizy składu chemicznego w mikroobszarach z użyciem przystawki EDS w skaningowym mikroskopie elektronowym oraz metodą dyfrakcji rentgenowskiej. Ponad to wykonano badania twardości oraz żarowytrzymałości łopatek poddawanych procesowi przesycania i starzenia w różnych czasach wytrzymania. Praca miała na celu określenie możliwości prowadzenia procesu aluminiowania metodą „above the pack” części z materiału EI-867 przy jednoczesnym określeniu wpływu procesu na zmianę żarowytrzymałości części. Na podstawie badań eksperymentalnych wykazano, że aluminiowanie łopatek turbin materiałem EI-867 metodą „above the pack” do uzyskania grubości warstwy w zakresie 0.03-0.06 mm możliwe jest w ciągu 10 godzin w temperaturze 950 ̊C. Aluminiowanie analizowaną metodą powoduje powstanie warstwy aluminiowanej o strukturze trójfazowej zapewniającej odpowiednią wytrzymałość powłoki. Wykazano jednak, że proces aluminiowania metodą "above the pack" z zastosowanym czasem 10 godzin powoduje znaczne obniżenie żarowytrzymałości materiału. Na podstawie uzyskanych wyników wykazano iż metoda bezkontaktowego aluminiowania w przypadku łopatek turbiny z materiału EI 867 nie spełnia wymogów lotniczych dla bezpiecznej eksploatacji ze względu na znaczne obniżenie własności mechanicznych.

3

Development of Turboshaft Engine Adaptive Dynamic Model: Analysis of Estimation Errors

Yepifanov Sergiy, Bondarenko Oleksiy

Transactions on Aerospace Research

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2022

|

Nr 4 (269)

59--71

EN

One of the most perspective directions of aircraft engine development is related to implementing adaptive automatic electronic control systems (ACS). The significant elements of these systems are algorithms of matching of mathematical models to actual performances of the engine. These adaptive models are used directly in control algorithms and are a combination of static and dynamic sub-models. This work considers the dynamic sub-models formation using the Least Square method (LSM) on a base of the engine parameters that are measured in-flight. While implementing this function in the (ACS), the problem of checking the sufficiency of the used information for ensuring the required precision of the model arises. We must do this checking a priori (to determine a set of operation modes, the shape of the engine test impact and volume of recorded information) and a posteriori. Equations of the engine models are considered. Relations are derived that determine the precision of parameters of these models’ estimation depending on the precision of measurement, the composition of the engine power ratings, and durability of observations, at a stepwise change of fuel flow. We present these relations in non-dimensional coordinates that make them universal and ready for application to any turboshaft engine.

4

Insight into Damping Sources in Turbines

Moneta Grzegorz

Fatigue of Aircraft Structures

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2022

|

Iss. 14

69--82

EN

Blade vibrations in aircraft engines are a significant challenge that must be overcome during the design and development of modern turbine engines. Vibrations lead to cyclic displacements and result in alternating stress and strain in undesired environments (high temperatures, erosion, corrosion of the surface, etc.). Under resonance conditions, stress amplitudes can increase and exceed their safety limits, and in extreme cases, can lead to engine failure. One method to reduce resonance vibrations is to increase damping in the turbine assembly. This paper presents and describes vibration damping sources in the turbine, including aerodynamic, material, and friction damping. Additionally, typical damping values for each damping component are presented and compared.

5

Rotating combustion chambers as a key feature of effective timing of turbine engine working according to Humphrey cycle – CFD analysis

Tarnawski Piotr, Ostapski Wiesław

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2022

|

Vol. 70, nr 5

art. no. e143100

EN

The paper presents a concept of a new turbine engine with the use of rotating isochoric combustion chambers. In contrast to previously analyzed authors’ engine concepts, here rotating combustion chambers were used as a valve timing system. As a result, several practical challenges could be overcome. An effective ceramic sealing system could be applied to the rotating combustion chambers. It can assure full tightness regardless of thermal conditions and related deformations. The segment sealing elements working with ceramic counter-surface can work as self-alignment because of the centrifugal force acting on them. The isochoric combustion process, gas expansion, and moment generation were analyzed using the CFD tool (computational fluid dynamics). The investigated engine concept is characterized by big energy efficiency and simple construction. Finally, further improvements in engine performance are discussed.

6

Simulations of fuels consumption in the CHP system based on modernised GTD-350 turbine engine

Hryniewicz Marek, Roman Kamil

Journal of Water and Land Development

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2021

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no. 51

250--255

EN

There were done simulations of fuels consumption in the system of electrical energy and heat production based on modernised GTD-350 turbine engine with the use of OGLST programme. In intention the system based on GTD-350 engine could be multifuel system which utilise post-fying vegetable oil, micronised biomass, sludge, RDF and fossil fuels as backup fuels. These fuels have broad spectrum of LHV fuel value from 6 (106 J•kg-1 ) (e.g. for sludge) to 46 (106 J•kg-1) (for a fuel equivalent with similar LHV as propan) and were simulations scope. Simulation results showed non linear dependence in the form of power function between unitary fuel mass consumption of simulated engine GTD-350 needed to production of 1 kWh electrical energy and LHV fuel value (106 J•kg-1). In this dependence a constant 14.648 found in simulations was multiplied by LHV raised to power - 0.875. The R2 determination coefficient between data and determined function was 0.9985. Unitary fuel mass consumption varied from 2.911 (kg•10-3•W-1•h-1) for 6 (106 J•kg-1) LHV to 0.502 (kg•10-3 •W-1 •h-1) for 46 (106 J•kg-1) LHV. There was assumed 7,000 (h) work time per year and calculated fuels consumption for this time. Results varied from 4,311.19 (103 kg) for a fuel with 6 (106 J•kg-1) LHV to 743.46 (103 kg) for a fuel with 46 (106 J•kg-1) LHV. The system could use fuels mix and could be placed in containers and moved between biomass wastes storages placed in many different places located on rural areas or local communities.

7

Insight Into Vibration Sources in Turbines

Moneta Grzegorz, Jachimowicz Jerzy, Pietrzakowski Marek, Doligalski Adam, Szwedowicz Jarosław

Fatigue of Aircraft Structures

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2021

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Iss. 13

40--53

EN

Despite of nearly 100 years of turbine engine development and design, blade vibrations remain a great engineering challenge. The rotating turbine blades’ vibrations lead to cyclic oscillations, which result in alternating stress and strain in harsh environments of high temperature and pressure. In modern aeroengines, high hot flow velocities might generate erosion and corrosion pitting on the metal surfaces, that leverage remarkably mean stresses. The combination of both mean and alternating stresses can lead to unexpected engine failures, especially under resonance conditions. Then, alternating stress amplitudes can exceed the safety endurance limit, what accelerates the high cyclic fatigue leading quickly to catastrophic failure of the blade. Concerning the existing state-of-the-art and new market demands, this paper revises forced vibrations with respect to excitation mechanisms related to three design levels: (i) a component like the blade design, (ii) turbine stage design consisting of vanes and blades and (iii) a system design of a combustor and turbine. This work reviews the best practices for preventing the crotating turbine and compressor blades from High Cyclic Fatigue in the design process. Finally, an engine commissioning is briefly weighed up all the pros and cons to the experimental validations and needed measuring equipment.

8

Experimental determination of compressor map of the DGEN 380 engine compressor using the WESTT CS/BV turbine engine simulator

Pazura Karolina, Orkisz Marek

Combustion Engines

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2021

|

R. 60, nr 2

26--31

EN

Currently aviation focuses mainlly on increasing the economy and ecology of engines. Production of NOx, CO2 and SO2 adversaly impacts the environment. Parallel goal to minimize SFC to achieve both lower: emission and mission costs. The optimization of components is thus very important. One of the ways of optimizing cycle is doing that based on compressor maps. However it is very expensive to plot one since experimental work needs to be done. The aim of this article is to present a methodology of creating compressor map based on ENGINE ANALOGY. There was used the virtual bench WESTT CS/BV for tests to receive pressure ratio and mass flow of DGEN 380 for three different values of flight speed and altitude, while the rotational speed was changed. The construction similarity of CFM 56-5B and APS 3200 gives the opportunity to plotted compressor maps using the engine analogy without the need for an experiment or using the virtual bench.

9

Aircraft turbine engine automatic control based on adaptive dynamic models

Yepifanov Sergiy

Transactions on Aerospace Research

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2020

|

Nr 4 (261)

61--70

EN

One of the most perspective development directions of the aircraft engine is the application of adaptive digital automatic control systems (ACS). The significant element of the adaptation is the correction of mathematical models of both engine and its executive, measuring devices. These models help to solve tasks of control and are a combination of static models and dynamic models, as static models describe relations between parameters at steady-state modes, and dynamic ones characterize deviations of the parameters from static values. The work considers problems of the models’ correction using parametric identification methods. It is shown that the main problem of the precise engine simulation is the correction of the static model. A robust procedure that is based on a wide application of a priori information about performances of the engine and its measuring system is proposed for this purpose. One of many variants of this procedure provides an application of the non-linear thermodynamic model of the working process and estimation of individual corrections to the engine components’ characteristics with further substitution of the thermodynamic model by approximating on-board static model. Physically grounded estimates are obtained based on a priori information setting about the estimated parameters and engine performances, using fuzzy sets. Executive devices (actuators) and the most inertial temperature sensors require correction to their dynamic models. Researches showed, in case that the data for identification are collected during regular operation of ACS, the estimates of dynamic model parameters can be strongly correlated that reasons inadmissible errors. The reason is inside the substantial limitations on transients’ intensity that contain regular algorithms of acceleration/deceleration control. Therefore, test actions on the engine are required. Their character and minimum composition are determined using the derived relations between errors in model coefficients, measurement process, and control action parameters.

PL

Jednym z najbardziej perspektywicznych kierunków rozwoju silnika lotniczego jest zastosowanie adaptacyjnych cyfrowych systemów automatycznego sterowania (ACS). Istotnym elementem adaptacji jest korekta modeli matematycznych zarówno silnika, jak i jego urządzeń wykonawczych oraz pomiarowych. Modele te pomagają rozwiązywać zadania sterowania i są połączeniem modeli statycznych i dynamicznych, ponieważ modele statyczne opisują relacje między parametrami w trybach ustalonych, a dynamiczne korygują odchylenia parametrów od wartości statycznych. W pracy rozważono problemy korekcji modeli z wykorzystaniem parametrycznych metod identyfikacji. Wykazano, że głównym problemem precyzyjnej symulacji silnika jest korekta modelu statycznego. W tym celu proponuje się procedurę opartą na szerokim zastosowaniu informacji a priori o osiągach silnika i jego układu pomiarowego. Jeden z wielu wariantów tej procedury przewiduje zastosowanie nieliniowego modelu termodynamicznego procesu pracy i oszacowanie poszczególnych poprawek charakterystyk elementów silnika z dalszym zastępowaniem modelu termodynamicznego przez aproksymację pokładowego modelu statycznego. Fizycznie uziemione oszacowania uzyskuje się na podstawie informacji a priori dotyczących oszacowanych parametrów i osiągów silnika, przy użyciu zbiorów rozmytych. Urządzenia wykonawcze (siłowniki) i najbardziej bezwładnościowe czujniki temperatury wymagają korekty ich modeli dynamicznych. Badania wykazały, że w przypadku, gdy dane do identyfikacji zbierane są podczas normalnej pracy ACS, oszacowania dynamicznych parametrów modelu mogą być silnie skorelowane, co powoduje niedopuszczalne błędy. Przyczyną są znaczne ograniczenia intensywności stanów nieustalonych, które zawierają regularne algorytmy sterowania przyspieszaniem / zwalnianiem. Dlatego wymagane są działania testowe na silniku. Ich charakter i minimalny skład określane są za pomocą wyprowadzonych relacji między błędami współczynników modelu, procesem pomiarowym i parametrami akcji kontrolnej.

10

On designing an expert diagnostic system of the aircraft turbine engine functional units

Borowczyk Henryk, Spychała Jarosław

Journal of KONBiN

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2020

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Vol. 50, iss. 1

171--192

EN

The paper presents issues related to the design of an expert diagnostic system of turbine engine functional units. Dedicated diagnostic stations and on-board flight data recorders are the sources of diagnostic signals. The signals were parameterized or identified dynamic models to get a compact representation in the form of a set of parameters. The set of diagnostic parameters was subjected to integer encoding. On this basis, a multi-valued diagnostic model describing the relationship between the set of faults and the set of symptoms (code values of diagnostic parameters) was determined. The proposed approach can be used in the design of expert diagnostic systems for propulsion units of any aircraft.

PL

W pracy przedstawiono zagadnienia związane z projektowaniem ekspertowego systemu diagnostycznego funkcjonalnych zespołów lotniczego silnika turbinowego. Sygnały z dedykowanych stanowisk diagnostycznych oraz pokładowych rejestratorów parametrów lotu poddano parametryzacji oraz identyfikacji modeli dynamicznych w celu uzyskania kompaktowej reprezentacji – zbioru parametrów. Zbiór taki poddano kodowaniu całkowito-liczbowemu. Wyznaczono wielowartościowy model diagnostyczny opisujący relacje między zbiorem uszkodzeń i zbiorem symptomów (kodowych wartości parametrów diagnostycznych). Zaproponowane podejście może być stosowane w projektowaniu ekspertowych systemów diagnostycznych zespołów napędowych dowolnego typu statków powietrznych – bezzałogowych i załogowych.

11

Badanie rezonansów lokalnych i złożonych w lotniczych zespołach napędowych z wykorzystaniem metod FAM-C i FDM-A

Lewitowicz Jerzy, Szelmanowski Andrzej, Gębura Andrzej, Pazur Andrzej, Franczuk Edyta

Przegląd Elektrotechniczny

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2019

|

R. 95, nr 11

59--62

PL

W artykule przedstawiono zagadnienia związane z badaniami lotniczych zespołów wirnikowych, a w szczególności ich łożysk tocznych i elementów przekładni zębatych. Opisano również podstawy teoretyczne badań i analizy zjawisk rezonansowych, identyfikowanych przy pomocy metod diagnostycznych FAM-C i FDM-A. Metody te oparte są na analizie modulacji napięcia wyjściowego prądnic i zapewniają monitorowanie zjawisk dynamicznych wszystkich podzespołów występujących w lotniczym zespole napędowym.

EN

The article presents the issues related to the research of aerodynamic rotor assemblies, in particular their rolling bearings and toothed gear components. The theoretical foundations of research and analysis of resonance phenomena, identified using the FAM-C and FDM-A diagnostic methods are also described. These methods are based on the analysis of generator output voltage modulation and provide monitoring of dynamic phenomena of all components found in the aviation power unit.

12

Influence of inlet geometry on the efficiency of 1 MW steam turbine

Koprowski Arkadusz, Gotowski Dominik, Rzadkowski Romuald, Szczepanik Ryszard

Journal of KONES

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2019

|

Vol. 26, No. 4

119--126

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.

13

Analiza uszkodzeń eksploatacyjnych oraz ich wpływ na pracę powierzchni kontaktowych w stopniu sprężarki osiowej

Kozakiewicz A., Grzejszczak O.

Mechanik

|

2018

|

R. 91, nr 7

517--519

PL

W trakcie eksploatacji elementy wirujące lotniczych silników turbinowych są narażone na liczne uszkodzenia, wynikające z trudnych warunków pracy tych podzespołów. W artykule przedstawiono przykładowe awarie silników lotniczych, spowodowane uszkodzeniami elementów sprężarki. Przeanalizowano wpływ wybranych uszkodzeń w obszarze pióra łopatki na pracę powierzchni kontaktowych w części wieńcowej tarczy i zamka łopatki oraz wyznaczono rozkłady naprężeń i ciśnień dla różnych zakresów pracy silnika. Analizy numeryczne wykonano z wykorzystaniem oprogramowania ANSYS.

EN

During the operation, rotating parts of aircraft turbine engines are exposed on different types of damage. These damages mostly ensure from the difficult work conditions of this components. The article presents examples of failure of aircraft engines resulting from damage to the compressor elements. The influence of exemplary damages in the area of the blade on the work of contact surfaces in the disk rim part and the blade footer was analyzed. The distribution of stresses and pressures was determined on assuming different ranges of rotational speed as well. Numerical analyzes were performed using the ANSYS software.

14

Prototype of the expert tribological diagnostic system of turbine engine

Borowczyk H., Zboiński M., Jóźwiak P., Dobosz K., Czarnecki A., Zarzycka E.

Journal of KONBiN

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2018

|

No. 48

323--340

EN

The article presents issues related to the construction of a prototype of an expert tribological diagnostic system for a turbine engine. The database consists of the results of tests on the chemical composition and concentration of the wear products in the oil sample as well as the physico-chemical parameters of the oil. For all diagnostic parameters, threshold values have been defined to classify the level of wear (normal, elevated, increased and emergency). PC Shell software enabling the combination of a rule representation of knowledge and procedural programming was used to build the expert system. The computer application consists of the main module and sources of knowledge dedicated to the applied research methods. The modular structure allows the development of an expert system by adding new research methods.

PL

W artykule przedstawiono zagadnienia związane z budową prototypu ekspertowego systemu diagnostyki tribologicznej lotniczego silnika turbinowego. Bazę danych stanowią wyniki badań składu chemicznego i koncentracji produktów zużywania w próbce oleju oraz parametry fizyko-chemiczne oleju. Dla wszystkich parametrów diagnostycznych określono wartości progowe w celu klasyfikacji poziomu zużywania (normalny, podwyższony, wzmożony i awaryjny). Do budowy systemu ekspertowego wykorzystano oprogramowanie PC Shell umożliwiające połączenie regułowej reprezentacji wiedzy oraz programowania proceduralnego. Aplikacja komputerowa składa się z modułu głównego oraz źródeł wiedzy dedykowanych zastosowanym metodom badawczym. Modułowa budowa pozwala na rozwój systemu ekspertowego przez dołączanie nowych metod badawczych.

15

Pulse powered turbine engine concept – numerical analysis of influence of different valve timing concepts on thermodynamic performance

Tarnawski P., Ostapski W.

Bulletin of the Polish Academy of Sciences. Technical Sciences

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2018

|

Vol. 66, nr 3

373--382

EN

The present work is an attempt to create the concept of an engine that will combine the benefits of a pulse powered piston engine and continuously powered turbine engine. The paper focuses on the subject of pressure gain combustion (PGC). A turbine engine concept with stationary constant volume combustors, working according the Humphrey cycle, is presented. Its work has to be controlled by valve timing system. Four different valve timing concepts were analyzed. Their influence on thermodynamic performance of engine was evaluated. Different valve constructions were researched by means of 3D numerical computational fluid dynamics (CFD) simulation.

16

Budowa modelu algorytmu genetycznego na potrzeby optymalizacji elementów konstrukcji silnika turbinowego

Kozakiewicz A., Kieszek R.

Mechanik

|

2017

|

R. 90, nr 7

603--605

PL

Przedstawiono wyniki optymalizacji tarcz sprężarek lotniczych silników turbinowych. Optymalizację grubości tarczy sprowadzono do problemu NP-zupełnego, który rozwiązano za pomocą jednego z algorytmów genetycznych (ewolucyjnego). Na kolejnych etapach pracy sprawdzano poprawność działania algorytmu optymalizacyjnego i algorytmu generującego dane. Porównano zoptymalizowaną tarczę wykonaną według technologii klasycznej z tarczą wykonaną w technologii BLISK.

EN

In this paper authors show results of optimization of compressor discs in turbine engines. The problem of optimizing the thickness of the disc brought to the NP-complete problem, and solved it by using one of the genetic algorithms – evolutionary algorithm. Correctness of model and optimization algorithm were constantly checked. At the end of this paper, compressor disc created due to traditional technology and disc created by BLISK technology were compared.

17

Analytical Performance Evaluation of Humphrey Cycle for Turbine Engine Application

Tarnawski P.

Machine Dynamics Research

|

2017

|

Vol. 41, No. 3

27--37

EN

A continuous effort of engineers is being striving to improve efficiency and reduce specific fuel consumption. High hope lies in pressure gain combustion field (PGC). The Humphrey ideal cycle delivers more than 10% higher efficiency than the Brytona-Joule cycle. The impact of the pressure ratio, adiabatic exponent, intercooling and heat regeneration was investigated in the paper. Engine efficiency according to analytical calculation reached 45%. The engine based on the Humphrey cycle can be realized as an pulse powered turbine engine. It should work according repeating cycle that consists of filling, combustion and exhaust. The cycle has to be controlled by the valve timing system. Due to the variable thermal parameters in the chamber, an effective expansion of the energy impulse required the nozzles with various ratio of outlet cross section to minimum cross-sectional. More precise efficiency estimation of pulse power turbine engine could be done by means of three dimensional numerical analysis with assumed geometry of valve timing design.

18

Validation of selected presented method measured of length fatigue gap on compressor blades forming during resonant tests

Kuźniar M., Bednarz A., Lichoń D., Witek L.

Journal of KONES

|

2017

|

Vol. 24, No. 3

151--158

EN

In this work, the validation of selected presented method measured of length fatigue gap was shown. The article describes three methods of determining fatigue gaps. The object of the study was the first stage compressor blade from aircraft engine. Blades have defects on the leading edge. This defect on the blade (as a result of the resonance vibration) was the origin point of the fatigue gap. Two of the methods, fluorescent and thermovision, were optical. The fluorescent method was a direct measurement, whereas direct-indirect thermography. The last of the presented methods was an analytical method, showing an algorithm based on amplitude-frequency characteristics. The advantages and disadvantages of these methods were compared. As a result of the analysis performed by the algorithm, there were specified patterns defining the dependence of change in crack length depending on the asymmetry of AF characteristics. The accuracy of the following methods and the results obtained for chord length were determined. Thanks to such use, these results have a utilitarian meaning. Such a compilation allowed us to evaluate the usefulness of particular measurement methods. Proposed methods of measuring the length of fatigue crack are used in experimental studies. It is also possible to implement them for research conducted during the operation of an aircraft engine.

19

A method of assessing the tendency of aviation fuels to generate thermal degradation products under the influence of high temperatures

Sarnecki J., Gawron B.

Journal of KONES

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2017

|

Vol. 24, No. 4

377--384

EN

The subject of the article concerns the issues associated with thermal degradation of aviation fuels under high temperature conditions. Due to the intensive development towards increasingly higher thermal loads for both, turbine aviation engines, as well as the used fuels, the issue of thermal stability of the fuel itself is extremely important. In aviation, the fuel, apart from direct participation in energy generation during the combustion process of a fuel-air mixture, also takes part in the heat transfer in many aircraft systems. As a result, requirements in terms of the fuel’s thermal potential are increasingly higher. The standard method for determining the thermal stability of fuel executed on a JFTOT device proves to be insufficient in the context of the appearing issues in current operation. The article presents a non-standard approach to the assessment of aviation fuel thermal degradation with the use of a specialist test rig. The authors believe that the presented methodology and the measurement capabilities of the test rig are valuable supplementary material for the standardized thermal stability test. It allows more thoroughly understanding the phenomena undergoing in the fuel impacted by high temperatures. The article has been prepared within the research project no. 2011/01/D/ST8/06567 funded by the National Science Centre in Poland.

20

SCOPUS as a meta-source of knowledge about turbine blade damage in the aspect of designing an expert diagnostic system

Borowczyk H., Błachnio J., Spychała J.

Journal of KONBiN

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2017

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No. 43

145--162

EN

The paper presents the concept of using the Scopus as a meta-source of knowledge about turbine blade damage in the aspect of designing an expert diagnostic system. In the first stage, the search was limited to the scope of the general term "turbine engine", followed by a refinement of the search terms within the area of rotary machines components degradation including their construction, manufacturing, repair technology and diagnostic methods. By using EndNote software in semi-automatic mode, specific issue groups have been designated. In the second stage, a query focused on the main causes of turbine blade damage and diagnostic methods was proposed. Using the Scopus-based search and archiving tools, one can systematically update the knowledge.

PL

W artykule przedstawiono koncepcję wykorzystania bazy Scopus jako meta-źródła wiedzy o uszkodzeniach łopatek turbin w aspekcie projektowania ekspertowego systemu diagnostycznego. W pierwszym etapie przegląd publikacji ograniczono do zakresu określonego ogólnym hasłem „turbine engine” a następnie doprecyzowano przeszukiwanie wprowadzając hasła szczegółowe z obszaru degradacji elementów maszyn wirnikowych z uwzględnieniem ich konstrukcji, technologii wytwarzania i naprawy oraz metod diagnozowania. Stosując oprogramowanie EndNote w trybie pół-automatycznym wyznaczono grupy publikacji dotyczących zagadnień szczegółowych co ułatwia wykorzystanie wyników kwerendy w procesie tworzenia ekspertowego systemu diagnostycznego. W drugim etapie zaproponowano kwerendę skoncentrowaną na głównych przyczynach uszkodzeń łopatek turbin oraz metodach diagnozowania. Wykorzystanie zawartych w bazie Scopus mechanizmów przeszukiwania oraz archiwizacji zbioru wyników umożliwia systematyczną aktualizację pozyskanej wiedzy.