Temat: aircraft modelling - Katalog OPAC zbiorów

Skocz do pozycji: 1.

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

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Skocz do pozycji: 2.

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

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Skocz do pozycji: 3.

Tytuł:: Selected problems concerning the analysis of thin-walled structures with the use of finite element method
Autorzy:: Jachimowicz, J.
Mańkowski, J.
Osiński, J.
Powiązania:: https://bibliotekanauki.pl/articles/243328.pdf
Data publikacji:: 2008
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: diagonal tension
wing structures
thin-walled structures
aircraft
FEM
modelling
Opis:: The aim of the paper was presentation and comparison of numerical methods applied in thin-walled structures analysis, with special attention paid to possibility of usage the Finite Element Method (FEM), especially in nonlinear analysis. There were presented basic differences between classical approach to modelling and analyzing thin-walled structures, and these performed with FEM methods using. The biggest emphasis was placed on the analysis of semimonocoąues, in which the loss in the shell 's stability is possible in the range of operational load activity. According to this, many nonlinear terms like global and local buckling, contact problems, significant deformations and shifts, are present. Worth emphasizing is the fact, that tension field, is something that was described long time ago. First paper s about this phenomenon were published in the last century. Although it is a common effect that takes place in semimonocoques, there are not many publications that analyze and examine this phenomenon. In this paper, an analysis of two-sided, thin-walled spar, which has undergone the flexion by the shearing force in the plane of the panel, was presented. The spar was designed as a classic semimonocoque, in which load transmission function is separated. It was assumed that, for the sake of small thickness, shell elements transmit mainly tangential loads, normal loads, when normal loads are transmitted by framework elements. Riveted joints are used to join elements of framework and shell. There are presented and compared results of analysis for models with various complexities. Firstly, results of analysis of classical model of semimonocoques were presented. It means that framework elements were modelled as rod elements transmitted only normal loads, but shell elements were modelled as disc semimonocoque elements, in this case transmitted only tangential loads. Area of section of rod elements was adequately increased, in order to consideration mating width, coming from partial transmission of normal loads by the shell elements. Results obtained for intermediate models were also presented, as well as for complex shell model, which allows on advanced nonlinear analysis of tension field, which consider contact between framework and shell elements. Applications of formulated models to thin-walled structure, especially aircraft ones and further possibilities of presented method of analysis were discussed.
Źródło:: Journal of KONES; 2008, 15, 1; 109-118
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Analysis of thermodynamic cycle influence of turbofan mixer engine on its performance
Autorzy:: Jakubowski, R.
Powiązania:: https://bibliotekanauki.pl/articles/245722.pdf
Data publikacji:: 2009
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: aircraft engines
turbojet engines
modelling of turbojet engines
turbojet engine characteristics
Opis:: The turbofan engines are widely used as propulsion of the contemporary airplanes. In the military application the turbofan mixer engines are used. Although the turbofan mixer engines are applied for a long time, the information about exact analysis of their thermodynamic cycle and performance are still in complete. The thermodynamic cycle of the turbofan mixer engine is presented and discussed in this paper. Based on it the cycle parameters selection is discussed. Then the optimization of turbofan mixer engine cycle is presented. Final results present the influence of chosen engine cycle parameters on the engine performance. The results are analyzed and discussed. On the basis of them the conclusions are formulated. It is not such an easy process to choose for the turbofan mixer engine thermodynamic parameters. It is connected with the fulfilment of two important rules. The equalization of total pressure of mixer inflow streamfor mixer efficient work is the first of it. The other rule is connected with engine cycle optimization. As it is shown it is not possible to choose engine parameters to reconcile the demands of specific thrust maximization and specific fuel consumption minimization. The engine thermodynamics parameters selection process is the search of the compromise between these two demand fulfilments, very often including engine mass analysis.
Źródło:: Journal of KONES; 2009, 16, 4; 171-178
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: The determination of accuracy of the demonstrator of aeronautic bevel gearbox, accomplished by selected rapid prototyping techniques using an optical scanner Atos II Triple Scan
Autorzy:: Marciniec, A.
Budzik, G.
Dziubek, T.
Sobolewski, B.
Zaborniak, M.
Powiązania:: https://bibliotekanauki.pl/articles/247540.pdf
Data publikacji:: 2014
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: bevel gear
aircraft gearbox
optical scanner
coordinate measuring technique
rapid prototyping
gear modelling
Opis:: Designing and manufacturing of aeronautic bevel gearboxes is a complicated and time-consuming process because of complex kinematics of the machining process as well as numbers of manufacturing methods. Machine manufacturers usually provide algorithms used in manufacture process. This requires substantial financial resources and, in consequence, it increases the costs of production. Using other commonly available calculation algorithm requires a lot of studies to verify whether the proposed gearbox works correctly. In order to reduce the manufacturing costs of prototypes, it is possible to use Rapid Prototyping methods. Using both Rapid Prototyping techniques and coordinate optical measurements enables to verify the correctness of assumptions made in the initial stage of product designing. This approach reduces significantly both prototyping time and manufacturing costs. In order to ensure the effectiveness of prototyping process, it is essential to provide the accuracy of manufactured prototypes. That is the reason why it is necessary to determine manufacturing methods that will ensure the highest geometric accuracy. The study presents the modelling and manufacturing process of aeronautic bevel gear of demonstrator taking into consideration the accuracy of selected Rapid Prototyping methods. The gear modelling is based on machining simulation method conducted in Autodesk Inventor. The measurement results are shown in displacement maps obtained with an optical scanner Atos II Triple Scan and universal GOM Inspect Professional software, which determines the prototype accuracy in relation to 3D-CAD models.
Źródło:: Journal of KONES; 2014, 21, 3; 205-209
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Dynamics analysis of the main landing gear in 3D model
Analiza dynamiczna podwozia głównego w modelu 3D
Autorzy:: Krasoń, W.
Małachowski, J.
Powiązania:: https://bibliotekanauki.pl/articles/247885.pdf
Data publikacji:: 2007
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: podwozie samolotowe
modelowanie numeryczne
zrzutowy test lądowania
MES (metoda elementów skończonych)
aircraft landing gear
numerical modelling
touchdown drop test
FEM
Opis:: Właściwie dobrane charakterystyki podwozia pozwalają minimalizować obciążenia występujące w podzespołach układu podwozia podczas jego pracy w momencie przyziemienia. W związku z tym wykonuje się analizy dynamiczne podwozi, aby przewidzieć ich zachowanie się w warunkach dla nich niebezpiecznych. Przeprowadzenie tego typu badań z wykorzystaniem metod numerycznych jest znacznie łatwiejsze i tańsze od prób stanowiskowych. W pracy omawiana jest metodyka modelowania podwozia głównego i procedury doboru parametrów opisujących rzeczywistą strukturę badanego układu. W celu określenia właściwości materiałowych elementów składowych układu podwozia definiowane są sprężyste i nieliniowe charakterystyki materiałowe. W modelu numerycznym MES uwzględniono następujące zagadnienia: kontakt pomiędzy współpracującymi częściami układu, zjawisko pochłaniania energii w amortyzatorze gazowo-cieczowym zastosowanym w podwoziu, oddziaływanie gruntu na odkształcalną oponę podczas przyziemienia. Wybrane wyniki analizy numerycznej odpowiadające przypadkowi maksymalnych obciążeń podwozia podczas przyziemienia na 3 punkty z maksymalną dopuszczalną prędkością pionową będą omawiane wraz z wynikami testów stanowiskowych. Prezentowana w pracy analiza jest pierwszą częścią badań numerycznych trwałości podwozia lotniczego.
Properly adjusted characteristics enable minimisation of loads that occur in the landing-gear components at the moment of touchdown. Therefore, dynamic analyses of the landing gear are conducted to provide capabilities to forecast their behaviour under hazardous conditions. This kind of investigation with numerical methods applied is much easier and less expensive than stand tests. However, the development of the landing gear FEM models is necessary. Methodology of the main landing gear numerical models developing and procedures of parameters selection for the real structure features representation is discussed in the paper. The nonlinear physical material properties were precisely defined. To describe material properties of all mechanical components of the landing gear, a materials chart describing parameters for the elastic range was used. In FEM model the following matters were taken into consideration: contact problems between collaborating elements, the phenomena of energy absorption by gas-liquid damper placed in the landing gear and the response of the landing gear during touchdown of a flexible wheel with the ground. Chosen results of the numerical analysis for the maximum load of the gear considered, corresponding to an aircraft's 3-point landing at maximum decline speed allowed have been compared to experimental research's results. The analysis presented in this paper is the first part of wider considerations concerning numerical assessment of landing gear life.
Źródło:: Journal of KONES; 2007, 14, 3; 305-310
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Comparison of internal processes effectiveness change influence the turbofan with and without mixer model sensitivity
Porównanie wrażliwości modelu silnika dwuprzepływowego z mieszalnikiem i bez mieszalnika na zmianę efektywności procesów wewnętrznych
Autorzy:: Jakubowski, R.
Powiązania:: https://bibliotekanauki.pl/articles/247564.pdf
Data publikacji:: 2008
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: silniki lotnicze
silniki odrzutowe
modelowanie silników odrzutowych
charakterystyki silnika odrzutowego
aircraft engines
turbojet engines
modelling of turbojet engines
turbojet engine characteristics
Opis:: At the present time one of the way of the aircraft engines improvement is the fuel consumption reduction but the thrust should stay on the same level. One of the ways to realize this is the engine internal processes improvement. Nowadays technology and the commuter design methods allows us produce more efficient compressors, fans, turbines etc. To manage the proper process of engine improvement, it is demand to know how the chosen elements improvement influences the engine work parameters. This knowledge allows us to calculate the cost, and evaluate the effects of the improvements. In the paper, the analyzes of chosen internal engine process improvement influence on the specific thrust and the specific fuel consumption is done for turbofan engine. The processes effectives are characterized by flow losses coefficients and the processes efficiencies. In the beginning the two types of turbofan engine wit and without mixer is described. The main differences in the engines model are presented. Then the process effectiveness coefficients are defined and research method is presented. The analysis, based on the small deviation methods is use to calculate the results of the work. Then the results are presented as comparison graphs for the engine with the mixer and without the mixer. The results are analyzed and discussed. In the last parts of the paper the conclusion are presented.
Współcześnie jedną z metod poprawy efektywności pracy silników lotniczych jest obniżanie jednostkowego zużycia paliwa, przy jednoczesnym niezmienianiu jego ciągu. Umożliwia to m.in. doskonalenie procesów wewnętrznych w silniku. Obecna technologia wytwarzania oraz komputerowe wsparcie procesów projektowania pozwala produkować zespoły silnika o coraz wyższej efektywności procesów wewnętrznych. Żeby optymalnie organizować proces podnoszenia efektywności pracy silnika wymagana jest znajomość wpływu modyfikacji efektywności poszczególnych zespołów na parametry użytkowe silnika. Umożliwia to oszacowanie kosztów i ocenę efektywności proponowanych modyfikacji silnika. W pracy przeprowadzono analizę wrażliwości modelu silnika dwuprzepływowego na zmianę efektywności procesów przepływowo-cieplnych w zespołach silnika. Efektywność procesów w zespołach silnika opisano poprzez wskaźniki strat ciśnienia oraz sprawności, zaś badanymi parametrami pracy silnika były ciąg jednostkowy i jednostkowe zużycie paliwa. Na początek scharakteryzowano dwa zasadnicze typy silników dwuprzepływowych - z mieszalnikiem i bez. Następnie przedstawiono przyjęty model silnika oraz wskaźniki oceny procesów wewnętrznych w zespołach i metodykę badań. W kolejnym kroku przeprowadzono badania z wykorzystaniem metod bazujących na metodzie małych odchyleń. Wyniki badań przedstawiono w postaci graficznej i omówiono porównując obydwie analizowane konstrukcje. Na koniec zaprezentowano wnioski do pracy.
Źródło:: Journal of KONES; 2008, 15, 3; 201-207
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Investigation of the turbofan with mixer engine model sensitivity of thermal-flow process modification in the engines components
Badania wrażliwości modelu silnika dwuprzepływowego z mieszalnikiem strumieni na zmianę efektywności procesów przepływowo-cieplnych w zespołach silnika
Autorzy:: Jakubowski, R.
Powiązania:: https://bibliotekanauki.pl/articles/244315.pdf
Data publikacji:: 2007
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: silniki lotnicze
silniki odrzutowe
modelowanie silników odrzutowych
charakterystyki silnika odrzutowego
aircraft engines
turbojet engines
modelling of turbojet engines
turbojet engine characteristics
Opis:: The turbofan with mixer engine model sensitivity of the thermal-flow processes effectiveness in the engine components changes was analyzed. The model of turbofan engine with the mixed exhaust stream is so complicated to use the small deviation methods to solve this problem. On that reason the own author methods to analyze this problem was proposed. During investigation it was revealed that the changes of some processes effectiveness leads to change of pressure inflow to the mixer and this cause to change of mixer process effectiveness. The mixer pressure drop coefficient decries so slightly but it should be taking into consideration during exact calculations. In the main parts of paper the results of simulation of engine work parameters sensitivity of the thermal-flow processes effectiveness changes is presented and discussed. The specific thrust and specific fuel consumption were chosen as the engine work parameters. The model responds for change of internal process effectiveness in all range and for small step was analyzed. The conclusions are presented in final parts of the paper. The essential influence on relations between the change of the efficiency of rotor sets and with specific parameters has compression rate of compressor. Generally the improvement performers of the excellence processes give better effects at the lower temperature value in front of the turbine.
Źródło:: Journal of KONES; 2007, 14, 4; 119-126
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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