Autor: Zalewski, W - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: A study of propeller for high altitude unmanned airplane
Autorzy:: Zalewski, W.
Powiązania:: https://bibliotekanauki.pl/articles/241661.pdf
Data publikacji:: 2015
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: unmanned high altitude aerial vehicles propeller-driven aircraft
genetic algorithm
lift coefficient distribution
Opis:: Over the last 20 years, we can observe growing interest in the field of unmanned high altitude aerial vehicles. Especially the light aircrafts with electric motors become popular. The use of electricity to drive enables application of non-conventional energy sources like solar energy. The propeller remains the best propulsion system for planes powered by electricity. High altitude planes powered by propellers are able to fly over the wide range of altitude: from 0 to 25 kilometres. Such wide range of altitude is connected with variability of propeller work conditions (for example the density of the air is changing 10 times) which remarkably complicate the process of matching propeller to motor. The paper presents optimization model of propeller destined to unmanned high altitude airplane. Computational procedure deals with searching optimal distribution of lift coefficient line along the blade span of the propeller to obtain maximal efficiency for selected altitudes of flight. Genetic algorithm was used during the searching procedure. The database of optimal solutions is created as a result of computation and can be later exploited for choosing the best solution able to meet the requirements. Because the same propeller is used for take-off, climb and high altitude flight, then the airfoils of the propeller blades must be capable of operating over an extremely different flow condition caused by large change in air density. Propeller blades airfoils are required to operate within a low Reynolds number (below 105) and high subsonic Mach number (up to 0.6) flow field during high altitude flight. At low Reynolds number, the airfoils generate lesser lift and higher drags. The performance of the airfoils and consequently of the whole propeller can decline significantly. The objective is to find airfoils with good performance in all condition, which can appear during the flight, and to find the best shape of lift coefficient curve along the blade span of the propeller. That is necessary in order to obtain acceptable efficiency of the propeller for all flight conditions.
Źródło:: Journal of KONES; 2015, 22, 4; 329-334
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Numerical simulation of vortex ring state phenomenon for the Mi2 type helicopter tail rotor
Autorzy:: Zalewski, W.
Powiązania:: https://bibliotekanauki.pl/articles/245648.pdf
Data publikacji:: 2016
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: air transport
helicopters
tail rotor VRS
Opis:: The paper presents computational simulations of loss of helicopter tail rotor effectiveness (LTE) effect caused by rotor vortex ring state (VRS) phenomenon. The phenomenon is critical for safety of helicopter operations and it was an important factor in some military and civil helicopters serious accidents. Analysis was conducted on the example of the tail rotor of Mi2 and PZL Kania single main rotor medium helicopters, which are still in wide use in some parts of the world. That kind of dual blades tail rotor was designed with symmetrical NACA0012 airfoil. Full three-dimensional analysis of the flow around real geometry of the rotor blades was conducted by application of commercial solver Ansys Fluent. The simulation was made by resolving Unsteady Reynolds Averaged Navier Stokes equations by finite volume method with use of Moving Mesh and Moving Reference Frame techniques. A hover turn over a spot was chosen as flight condition of helicopter, which could induce the LTE phenomenon. Thrust and power consumption were estimated during computations. Visualization of the flow field and pathlines of the flow were presented for chosen stages of vortex ring formulation around the rotor. The sensitivity of dual blades tail rotors, which are popular in light and medium type of helicopters to LTE phenomenon, was estimated.
Źródło:: Journal of KONES; 2016, 23, 2; 437-442
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Computational model of high altitude aircraft aerodynamics
Autorzy:: Zalewski, W.
Powiązania:: https://bibliotekanauki.pl/articles/242754.pdf
Data publikacji:: 2016
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: transport
air transport
simulation
propeller-driven unmanned airplane
propeller-wing interaction
low Reynolds number flows
Opis:: The paper presents computational fluid dynamics hybrid model for analysis of complex flow composed of flow zones at low Reynolds number and flow zones at relatively high Reynolds number conditions. In the described model both ranges of the flow are separated and resolved independently using different way of simulation. That kind of phenomenon is typical for aerodynamics of unmanned propeller driven aircrafts operating at very high altitude conditions (stratospheric). That type of aerial vehicles is now used for military and scientific purposes. In many cases, the wings of a plane are operating at relatively high Reynolds number flow conditions and low angles of attack while the parts of the propeller blades are working at low Reynolds number flow condition and high angles of attack. Described numerical model was used for analysis of the impact of working propellers on the aerodynamics of the aircraft. Analysis was made on the example of a twin-engine, unmanned aircraft with electric motors during the high altitude flight. Three configurations were studied and compared: the plane without propellers, the plane with pusher propellers and the plane with tractor propellers. For each configuration, distributions of aerodynamic coefficients along the span of the wing and their global values for the entire aircraft were estimated. Calculations were performed using the Fluent solver with implementation of a model of propeller based on the Blade Element Theory. Results of the analysis indicate a slight advantage of the tractor propellers configuration.
Źródło:: Journal of KONES; 2016, 23, 1; 437-444
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Computational design and optimisation of innovative, high-efficiency wind turbine
Autorzy:: Stalewski, W.
Zalewski, W.
Powiązania:: https://bibliotekanauki.pl/articles/246604.pdf
Data publikacji:: 2015
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: green power
wind turbine
computational fluid dynamics (CFD)
computer-aided design
optimisation
Opis:: New concept of innovative, high-efficiency wind turbine has been developed and optimised. The turbine consists of a rotor with a vertical axis of rotation and a ring-palisade casing, which task is to deflect wind stream so that it flows perpendicularly to the rotor plane. The main advantage of such configuration of a wind turbine is that due to the vertical axis of symmetry, it works independently on the wind direction and it does not need any mechanism directing it towards the wind. The greatest challenge when designing the turbine was to minimise losses of energy of the wind stream deflected by 90 degrees by the ring vanes of the casing. This involved optimisation of number, shapes and mutual positions of the ring vanes. The whole optimisation works were done based on computational methods of Computer-Aided Design and Optimisation and Computational Fluid Dynamic. Subsequent variants of the ring-palisade casing were designed using an appropriately adapted in-house-software package supporting design and optimisation of multi-element airfoils. Three-dimensional analysis of flow around and inside the casing was conducted by application of commercial URANS solver ANSYS FLUENT. Eventually designed turbine is characterised by high efficiency in respect of acceleration of the wind stream. On the basis of computer simulations, it is estimated that the average velocity of air stream flowing through the rotor plane may be higher than the wind speed by about 45%. Extent of the acceleration of the wind stream partially depends on the number of ring vanes comprising a casing. Depending on specificity of application, this number of ring vanes may be chosen by a compromise between performance and dimensions of the turbine. The proposed wind turbine seems to be very promising solution, especially within the area of small and moderate renewable-energy sources, which in particular may be placed directly in residential-building areas, e.g. on the roofs of houses. This type of renewable-energy sources may also be successfully used in the field of environmentally friendly transport, in the process of producing hydrogen as fuel for fuel cell vehicles.
Źródło:: Journal of KONES; 2015, 22, 2; 221-232
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Aerodynamic effect of turbo prop engine slipstream on aircraft tail assembly vibration
Autorzy:: Zalewski, W.
Stalewski, W.
Powiązania:: https://bibliotekanauki.pl/articles/241875.pdf
Data publikacji:: 2017
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: air transport
aerodynamic wake
nacelle
tail assembly
vibration
Opis:: The article presents a computational analysis of the effect of the turboprop engine slipstream on generation of aerodynamic forces induced vibrations of aircraft tail assembly (empennage). Working propellers exhaust system, engine nacelle, and wing-engine nacelle flow interference phenomenon can cause strong non-stationary disturbances behind the wing of the aircraft. These disturbances, propagating in the direction of the aircraft tail assembly, may be an important factor influencing the operation of the airplane flow control system and the source of aerodynamic forces generating vibrations of the entire plane structure. The article presents an example of analysis of this phenomenon for a light passenger-transport aircraft using advanced numerical models for simulation of the flow around the aircraft. In the computational model, Navier-Stokes flow equations were solved by finite volume method with the K-Omega SST turbulence model to calculate the turbulent kinetic energy distribution in the flow slipstream behind the airplane propulsion unit. The Ansys Fluent commercial solver was used to run analyses. To perform the simulation, high quality, dedicated conformal computational mesh, consisting of hexahedral and tetrahedral elements was prepared to evaluate the propagation of the flow disturbances with limited numerical dispersion effect. Mesh generation was conducted using Ansys ICEM CFD and Mesher software. Unsteady aerodynamic forces for horizontal and vertical tail-planes of the airplane were computed during simulations. Fourier analysis of the driven forces was performed, which resulted in finding the dominating vibration frequencies generated by the flow field around the tail assembly. The visualization of the flow field and the regions of the strong disturbances were presented. Results can be exploited in the pre-design process of aerodynamic configuration of multi-engine aircrafts.
Źródło:: Journal of KONES; 2017, 24, 4; 363-367
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Analysis of wing-engine nacelle aerodynamic interference
Autorzy:: Zalewski, W.
Stalewski, W.
Powiązania:: https://bibliotekanauki.pl/articles/243801.pdf
Data publikacji:: 2017
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: air transport
nacelle-wing integration
flow separation
adjoint solver
parametric design
Opis:: The article presents an analysis of the wing-engine nacelle flow interference phenomenon on the example of a light twin-engine commuter aircraft. The problems of propulsion system integration with the wing in airplanes are now frequently the subject of advanced optimization research performed by aircraft manufacturers. The shape of the engine nacelle and its connection with the wing determines the quality of the flow around the wing in that area. This is important for high-lift devices placed at the wing trailing edge behind engine nacelle used during the take-off and landing process. Additionally the flow is effected by the disturbances generated by working propellers, the presence of air inlets and an exhaust system of the engine. The article presents a process of numerical optimization of an engine nacelle rear part shape. The main goal of the process was to eliminate the flow disturbances caused by the engine nacelle-wing interference phenomenon. During analysis, the Adjoint Solver method was used to designate nacelle body areas where modification should have the most important impact on the flow quality. The results obtained from adjoint solver were used in the process of finding the optimum shape of the rear part of the nacelle using a parametric geometry generator powered by Ansys Design Modeler and PARADES software. Comparative computational analysis for selected geometries of the engine nacelle was performed using commercial Ansys Fluent solver. Ansys Fluent is an advanced computational solver based on the finite volume method for solving the Navier-Stokes flow equations. Several dozen of geometric shapes were analysed in the optimization process of the nacelle rear part. The final result was the shape of the engine nacelle with correct flow without separation and vortex structures. The article presents results of calculations and visualization of the flow pattern for analysed cases.
Źródło:: Journal of KONES; 2017, 24, 3; 339-344
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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