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1
Content available Gurney flap and T-strip alternativesin application to typical aircraft steer surface
Sieradzki A.
Journal of KONES
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2018
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Vol. 25, No. 1
347--354
EN
Classic Gurney flap and double Gurney flap (called T-strip) are well-researched trailing edge modifications used in aerospace engineering. However, one of the inevitable effects of their use is the aerodynamic drag increase at low lift conditions, concerned as the major drawback of these solutions. This article presents Gurney flap and T-strip passive alternatives, which guarantee similar advantages in terms of e.g. lift enhancement, but without significant drag increase. Their aerodynamic analysis was performed on the application case of a typical symmetrical aircraft stabilizer with movable steer. Both solutions, consisting of plates nearly parallel to the direction of flow, were modelled as two-dimensional cases and CFD calculations were performed for specified range of angles of attack and steer deflections. Obtained aerodynamic characteristics allowed assessing the influence of selected modifications on the stabilizer effectiveness, as well as on hinge moment characteristics. The flow pattern changes in the presence of analysed devices were also investigated. In this way, performed analysis provided valuable information about the advantages and disadvantages of using of such devices in comparison to classic Gurney Flap and double Gurney flap. The results showed that using proposed solutions gives the possibility of significant reduction of the aerodynamic drag of the whole stabilizer at low lift conditions, while still maintaining favourable lift characteristics.
2
Content available Determination of ice deposit shape and ice accretion rate on airfoil in atmospheric icing conditions and its effects on airfoil characteristics
Sznajder J., Sieradzki A., Stalewski W.
Journal of KONES
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2017
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Vol. 24, No. 2
271--278
EN
Simulations of ice accretion on airfoil in icing conditions were conducted using ice accretion model implemented by authors in ANSYS FLUENT CFD solver. The computational model includes several sub-models intended for simulations of two-phase flow, determination of zones of water droplets impinging on the investigated surface, flow of water in a thin film on airfoil surface and heat balance in air-water-ice contact zone. The method operates in an iterative loop, which enables determination of effects of gradual deformation of aircraft surface on airflow over the surface, which has impact on distribution of collected water, flow of water film over the surface and local freezing rates. The implementation of the method in CFD solver made it necessary to complement the mathematical model of determination of local rates of deformation of aircraft surface with modification of computational mesh around the surface, which must conform, to the deformed surface. Results of simulated ice accretion on NACA 0012 airfoil were compared with results of experiment conducted in icing wind tunnel for a 420 s long process of ice accretion in steady-flow, steady angle-of-attack conditions. Close agreement of values and location of maximum ice thickness obtained in experiment and in the flow, simulations can be observed. For the airfoil deformed with ice, contour determination of its aerodynamic characteristics at several other angles of attack was conducted proving dramatic degradation of its aerodynamic characteristics due to ice deformation.
3
Content available Gurney flap and T-strip influence on stabilizer aerodynamic effectiveness and hinge moment characteristics
Sieradzki A.
Prace Instytutu Lotnictwa
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2016
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Nr 4 (245)
199--208
EN
Classic Gurney flap and double Gurney flap (called T-strip) are well researched devices in fixed wing applications. However, their influence on aircraft movable steer aerodynamic characteristics is not widely documented. This paper presents aerodynamic analysis of these two airfoil trailing edge modifications, applied to a typical symmetrical aircraft stabilizer with movable steer. Both solutions were modelled as two dimensional cases and CFD calculations were performed for a selected range of angles of attack and steer deflections. As a result, a set of aerodynamic characteristics was received. They allowed to assess the influence of selected modifications on entire stabilizer aerodynamic effectiveness, as well as on hinge moment characteristics. The flow conditions change in the presence of the analyzed devices were also investigated. This way, performed analysis provided valuable information about advantages and disadvantages of using such devices on small aircrafts control surfaces. The results showed the possibility of significant improvement of the aerodynamic characteristics of the whole stabilizer by using Gurney flap or T-strip, especially at high steer deflection angles and moderately high lift coefficient values.
PL
Klasyczna klapka Gurneya oraz podwójna klapka Gurneya (T-strip) są dobrze przebadanymi urządzeniami w zastosowaniu do stałych płatów. Ich wpływ na charakterystyki aerodynamiczne ruchomych powierzchni sterowych nie jest jednak szeroko udokumentowany. W publikacji przedstawiono analizę aerodynamiczną dwóch wspomnianych modyfikacji krawędzi spływu profilu, w zastosowaniu do typowego dla statków powietrznych symetrycznego statecznika z ruchomym sterem. Obydwa rozwiązania zamodelowano jako przypadki dwuwymiarowe, a następnie przeanalizowano przy pomocy metod CFD dla szeregu kątów natarcia oraz wychyleń steru. W rezultacie otrzymano zestaw charakterystyk aerodynamicznych. Pozwoliły one na ocenę wpływu wybranych modyfikacji na efektywność aerodynamiczną kompletnego statecznika, jak również na charakterystyki momentu zawiasowego. Zbadano również zmiany jakie zachodzą w przepływie w obecności analizowanych urządzeń. Tym sposobem, przeprowadzona analiza dostarczyła cennych informacji dotyczących zalet i wad użycia tego typu rozwiązań na powierzchniach sterowych niewielkich statków powietrznych. Rezultaty wykazały możliwość znacznej poprawy charakterystyk aerodynamicznych całego statecznika w wyniku zastosowania klapki Gurneya lub typu T-strip, zwłaszcza przy dużych wychyleniach steru i umiarkowanie dużych wartościach współczynnika siły nośnej.
4
Content available Propulsion configuration effect on performance of an inverted joined wing airplane
Galiński C., Sieradzki A., Kalinowski M.
Journal of KONES
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2016
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Vol. 23, No. 3
135--141
EN
Efficiency is crucial for an airplane to reduce both costs of operations and emissions of pollutants. There are several airplane concepts that potentially allow for increasing the efficiency. A few of them were not investigated thoroughly enough yet. The inverted joined wing configuration, where the upper wing is positioned in the front of the lower one is an example of such a concept. Therefore, a project consisting of an aerodynamic analysis and optimisation, development of the software for multidisciplinary optimisation, development of an electric propulsion system, development of an experimental scaled demonstrator, wind tunnel testing and flight-testing was undertaken by consortium led by the Institute of Aviation, including also Warsaw University of Technology, Air Force Institute of Technology and small company MSP. Results of this project led to the conclusion that inverted joined wing configuration allows to build an airplane with the best performance in the world, but its advantage against conventional airplanes is marginal. One reason for this is large trimming drag of the configuration with relatively high position of the thrust vector. Therefore, other configurations of the propulsion were also considered to see if airplane performance could be further improved. This effort is described in the present paper.
5
Content available Aeroelastic analysis of helicopter rotor using virtual blade model and equivalent beam model of a blade
Sieradzki A.
Journal of KONES
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2016
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Vol. 23, No. 1
297--304
EN
Modern helicopter rotor blades design requires taking into account complex aeroelastic phenomena. Sophisticated computational fluid dynamics and structural dynamics models, available on the market, coupled together enable such analysis with very high fidelity. However, the computational cost of this type of simulation is usually very high and for this reason, it cannot be used in interactive design process or optimization run. Complex Fluid Structure Interaction models are excellent tools for validation purposes, but the design process requires simpler models with lower computational cost and still relatively high accuracy and capabilities. The paper presents a new efficient methodology for calculating helicopter rotor loads, deformations and performance. It uses the well-known Navier-Stokes equations aerodynamic solver – ANSYS Fluent, and modified Virtual Blade Model (based on Blade Element Theory) for rotor flow calculation. This connection guarantees exceptional capabilities and fidelity in comparison with simulation time. The dedicated structural dynamics solver, based on equivalent beam model of a blade and Finite Difference Method, was developed and coupled with CFD part using User Defined Functions in Fluent software. The accuracy of created module was validated with wind tunnel tests data of IS-2 helicopter rotor model, performed in Institute of Aviation. The results of calculations were compared with experimental data for a hover state and a forward flight with three different flight velocities. The comparisons showed very good agreement of the data in most of the analysed cases and pointed out new research possibilities. The presented aeroelastic helicopter rotor model combines all advantages of using three-dimensional Navier-Stokes solver with relatively low computational costs and high accuracy, confirmed by wind tunnel tests. It could be used successfully in helicopter rotor blades design process.
6
Content available Performance comparison of the optimized inverted joined wing airplane concept and classical configuration airplanes
Sieradzki A., Dziubiński A., Galiński C.
Archive of Mechanical Engineering
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2016
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Vol. LXIII, nr 3
455--470
EN
The joined wing concept is an unconventional airplane configuration, known since the mid-twenties of the last century. It has several possible advantages, like reduction of the induced drag and weight due to the closed wing concept. The inverted joined wing variant is its rarely considered version, with the front wing being situated above the aft wing. The following paper presents a performance prediction of the recently optimized configuration of this airplane. Flight characteristics obtained numerically were compared with the performance of two classical configuration airplanes of similar category. Their computational fluid dynamics (CFD) models were created basing on available documentation, photographs and some inverse engineering methods. The analysis included simulations performed for a scale of 3-meter wingspan inverted joined wing demonstrator and also for real-scale manned airplanes. Therefore, the results of CFD calculations allowed us to assess the competitiveness of the presented concept, as compared to the most technologically advanced airplanes designed and manufactured to date. At the end of the paper, the areas where the inverted joined wing is better than conventional airplane were predicted and new research possibilities were described.
PL
Układ skrzydeł połączonych jest niekonwencjonalną konfiguracją samolotu, znaną od lat 20. ubiegłego stulecia. Cechuje go kilka istotnych zalet, takich jak redukcja oporu indukowanego oraz masy samolotu, ze względu na koncepcję zamkniętego skrzydła. Samolot w odwróconym układzie skrzydeł połączonych jest rzadko rozpatrywanym wariantem tej konfiguracji, z przednim skrzydłem usytuowanym nad skrzydłem tylnym. Niniejszy artykuł przedstawia oszacowanie osiągów zoptymalizowanej wersji tego typu samolotu. Charakterystyki aerodynamiczne, uzyskane na drodze obliczeń numerycznych CFD (Computational Fluid Dynamics – obliczeniowa mechanika płynów), zostały porównane z osiągami dwóch samolotów zbliżonej kategorii o układzie klasycznym. Ich modele obliczeniowe zostały stworzone bazując na dostępnej dokumentacji, zdjęciach oraz metodach projektowania odwrotnego. Analiza obejmowała symulacje wykonane dla skali bezzałogowego demonstratora o rozpiętości skrzydeł 3 m oraz pełnowymiarowej skali, odpowiadającej załogowym samolotom. Tym sposobem, wyniki obliczeń CFD pozwoliły ocenić konkurencyjność zaprezentowanej koncepcji, w porównaniu do najbardziej zaawansowanych technologicznie, obecnie projektowanych i budowanych, samolotów. Na końcu artykułu wskazano obszary, w których odwrócony układ skrzydeł połączonych charakteryzują potencjalnie lepsze osiągi niż układ konwencjonalny i zaproponowano dalszy możliwy kierunek prac.
7
Content available Resonance phenomenon in the quartzite from Jegłowa (Poland)
Marciniszyn T., Sieradzki A., Poprawski R.
AGH Journal of Mining and Geoengineering
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2013
|
Vol. 37, no. 1
51--58
EN
The quartzite rock has been characterized by dielectric investigation. On the basis of complex dielectric measurements in a wide temperature (50-320 K) and frequency (10/2—3 x 10/7 Hz) ranges the resonance at about 20 MHz was found. The proposed method is based on the resonance phenomenon which allows for the detection of grains of quartz and calculates their size in the studied material. Based on this method, the average size of the quartz grains (0.16 mm and 0.14 mm) embedded into quartzite was determined. Dielectric measurements of the quartzite samples annealed at 800°C, 900°C and 1000°C were performed. Results from the analysis using X-ray fluorescence (XRF) showed that the chemical composition remains unchanged after the thermal treatment, despite of the well-known crystal structure changes.
PL
Kwarcyt został scharakteryzowany dzięki pomiarom dielektrycznym. Na podstawie pomiarów dielektrycznych przeprowadzonych z szerokim zakresie temperatur (50-320 K) oraz częstotliwości (10/2--3 • 10/7 Hz) został pokazany rezonans w okolicy 20 MHz. Zaproponowano metodę bazującą na zjawisku rezonansu, pozwalającą wykryć oraz obliczyć wielkości ziaren kwarcu w badanym materiale. Bazując na tej metodzie, wyznaczono średni rozmiar ziaren kwarcu w kwarcycie: 0,16 mm oraz 0,14 mm. Przeprowadzono także pomiary dielektryczne kwarcytu wygrzanego w temperaturze 800°C, 900°C oraz 1000°C. Analiza fluorescencyjna XRF pokazała, że skład chemiczny po wygrzewaniu nie zmienia się pomimo zmiany struktury.
8
Content available Anisotropy properties of the quartzite from Jegłowa, Poland
Marciniszyn T., Sieradzki A.
Acta Geologica Polonica
|
2013
|
Vol. 63, no. 2
265--269
EN
Results of the dielectric spectroscopy, thermal and dilatometric measurements of the quartzite rock are presented. Based on the dielectric measurements performed in a wide range of the frequency (101 – 5 • 107 Hz) at temperature of 300K the piezoresonance in quartzite was found. A chemical composition of quartzite was examined by XRF. The anisotropy of the thermal conductivity was observed. The thermal conductivity coefficient changes from 13.2 [W/Km] to 5.6 [W/Km] for the [100] and [001] direction, respectively. Based on the thermal expansion measurement the thermal expansion coefficient of quartzite was estimated to be αQ = 8.0 • 10-6 [K-1] ±0.7 • 10-6.
9
Content available remote Size effect and dielectric properties of NH4H2PO4 - porous glass composites
Ciżman A., Komar J., Marciniszyn T., Poprawski R., Rysiakiewicz-Pasek E., Sieradzki A.
Materials Science Poland
|
2012
|
Vol. 30, No. 2
143--150
EN
NH4H2PO4 nano-composite antiferroelectric materials in porous glass have been studied by means of dielectric and dilatometric investigations. Dielectric spectroscopy measurements in a wide frequency range are reported here for the first time, for both the antiferro- and paraelectric phases of ammonium dihydrogen phosphate (ADP) embedded in a porous matrix. Low frequency relaxation processes above the phase transition temperature were shown to occur. An investigation of the thermal expansion revealed a negative volume jump at the phase transition point. It was found that the phase transition temperature in ADP crystals embedded in porous glass decreased with the decrease of the mean pore size. The experimentally observed shift of the phase transition temperature is caused by a combination of size and pressure effects.
10
Content available Selected properties of amphibolites and migmatites from the G.A.M. Kluczowa Mine
Marciniszyn T., Sieradzki A.
AGH Journal of Mining and Geoengineering
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2012
|
Vol. 36, no. 4
75-81
EN
In this paper we present the results of thermal conductivity, thermal expansion and water absorption measurements of the migmatite and amphibolites rocks. The studies are intended to classify migmatites and amphibolites in terms of their practical application. The results revealed that investigated materials can be used as a construction material with good thermal and visual properties.
PL
W artykule przedstawiono wyniki badań przewodności cieplnej, rozszerzalności termicznej, jak również nasiąkliwości wodnej migmatytu i amfibolitu. Przeprowadzone badania mają na celu sklasyfikowanie migmatytu i amfibolitu pod względem ich praktycznego zastosowania. Wyniki wykazały, że badane materiały skalane mogą być wykorzystane jako materiał konstrukcyjny charakteryzujący się dobrymi właściwościami termicznymi oraz wizualnymi.
11
Content available remote Stacje uzdatniania wody i nowoczesne systemy sterowania
Rybak J., Sadowski J., Sieradzki A.
Napędy i Sterowanie
|
2000
|
R. 2, nr 7/8
40--41
PL
Woda jako podstawowy element środowiska, w którym żyjemy, jest obok powietrza głównym składnikiem potrzebnym do życia. Ze względu na tak duże znaczenie, jakie spełnia w naszej codziennej egzystencji, bardzo ważna jest jej jakość. Woda przeznaczona do celów spożywczych powinna spełniać wymagania stawiane przez Rozporządzenie Ministra Zdrowia i Opieki Społecznej, w którym szczegółowo określono parametry fizyko-chemiczne i biologiczne, jakim powinna odpowiadać. Przygotowanie wody zarówno do celów spożywczych jak i przemysłowych stawia bardzo wysokie wymagania firmom zajmującym się problematyką oczyszczania i uzdatniania wody.
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