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Wyświetlanie 1-15 z 161
Tytuł:
New designs of centrifugal magnetic fluid seals for rotating shafts in marine technology
Autorzy:
Matuszewski, Leszek
Powiązania:
https://bibliotekanauki.pl/articles/260045.pdf
Data publikacji:
2019
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
magnetic fluids
ferrofluids
lubricants
magnetic seals
static seals
rotational seals
Opis:
The centrifugal magnetic fluid seals have important advantage over the conventional centrifugal seals. They maintain very good sealing capacity at static, medium and high speeds of shaft rotation, with the increased seal lifetime, and minimum torque and static friction. These seals are particularly useful in cases when the angular shaft velocity varies and sometimes decreases to nearly or exactly zero, such as in flywheel applications, ship propeller main shafts, etc. Unique properties of the magnetic fluid give rare opportunities for application in marine design, where perfect sealing together with reliable lubrication are required. The paper presents a typical design and operation principle of a centrifugal magnetic fluid shaft seal, along with new design solutions. Not only in ocean technology and underwater robotics. Some cases of application of centrifugal magnetic fluid seals in modern sealing technology are included.
Źródło:
Polish Maritime Research; 2019, 2; 33-46
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of a face seal’s operational parameters on test bench
Autorzy:
Gacek, J.
Norymberczyk, Ł.
Płonka, S.
Powiązania:
https://bibliotekanauki.pl/articles/114411.pdf
Data publikacji:
2015
Wydawca:
Stowarzyszenie Inżynierów i Techników Mechaników Polskich
Tematy:
face seals
testing of the seals
Opis:
The paper presents a method for determination of static characteristics of a gas lubricated face seal on the basis of experiment performed on the test bench. It has been developed a mathematical model QN=f(tg, pg, n) depicting effect of temperature of the gas tg, pressure of the gas pg and rotational speed of the shaft n on flow rate value of the gas QN. This dependency was used to determine pressure of the gas required for a selected operational parameters of the machine. To asses correctness of functioning of the seal it has been performed measurements of a selected 3D roughness parameters of the sealing rings. Slight changes in values of the 3D surface roughness of stationary and rotating rings before and after 25 working hours allow for conclusion about nearly contactless character of operation of the seal.
Źródło:
Measurement Automation Monitoring; 2015, 61, 12; 555-560
2450-2855
Pojawia się w:
Measurement Automation Monitoring
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Blade-type piston compressor investigation of seals
Autorzy:
Kalina, P.
Chomczyk, W.
Irzycki, A.
Snopkiewicz, K.
Powiązania:
https://bibliotekanauki.pl/articles/246203.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
piston machines
piston compressor
seals testing
Opis:
The paper presents the test results of selected seals applied in the blade-type piston compressor designed and realized in Propulsion Department of Institute of Aviation according to Patent No 6822 specification. Principle of operation of the compressor and the construction of test stand utilized to the seals testing were presented in the paper published in the Journal of KONES 2009. The special blade-type piston realizes a pendulous movement in the circular cylinder divided into two bulkheads. Each of bulkheads, fitted out with a set of bidirectional operating valves, creates by sequential opening and closing of them two compression chambers for one blade. Comprehensive tests of different kinds of seals were carried out on a single-compression machine driven by pneumatic actuator. The pressure rise vs. blade movement and drop of pressure when the piston was stayed at top dead centre were measured. The results of leak tightness of other structures of blade-type piston were analyzed as well and are subject to the following paper. The new design of piston relied on fitting-out of piston with side disc was prepared with intention of eliminating the loss of usable pressure in compression chamber, especially in area of top dead centre. The proposed design eliminated the leaks on the drive shaft and lateral seals, but not on the cylindrical surface of disco.
Źródło:
Journal of KONES; 2010, 17, 1; 199-204
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Trajectory of the apex seals of the wankel rotary engine
Autorzy:
Drogosz, P.
Powiązania:
https://bibliotekanauki.pl/articles/242183.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
internal combustion engines
Wankel rotary engines
trochoid
seals
equidistant
Opis:
This article describes the basic principles for determining the trajectory of the apex seals of Wankel rotary engines. An attempt is made as the Wankel engine seems to be the convenient as the burning hydrogen fuel engine. The main advantage is particularly intensive cooling. The main disadvantage is high pollution of combustion gases. Analyzing the working constructions it is possible to find the main sources of pollution. After all it seems that specific work of rotating piston seals are the main reason of usage big volume of lubrication oil. But part of lubrication oil is burnt together with the fuel increasing the pollution. Even using hydrogen as fuel it remains difficult to meet EURO V regulations of combustion gases pollution made by transport vehicles. Every possibility of volume reduction of lubrication oil is important. In the article the trajectories of apex seals are discussed. As the mathematical model of trajectory a special formula of trochoid was chosen. The main advantages of the chosen form of mathematical equation are applications of two main parameters: curve size parameter and dimensionless curve parameter. These two parameters decided about convenience in changing volume of internal combustion engines and comparisons of performance characteristic of different Wankel engines. In other publications connected with Wankel motors more complicated mathematic formulas are still used.
Źródło:
Journal of KONES; 2011, 18, 2; 117-122
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Evaluation of leakage through labyrinth seals with analytical models
Autorzy:
Szymański, Artur
Dykas, Sławomir
Powiązania:
https://bibliotekanauki.pl/articles/1954459.pdf
Data publikacji:
2014
Wydawca:
Politechnika Gdańska
Tematy:
labyrinth seals
analytical methods
experiment
turbomachinery
gas turbine
validation
Opis:
Secondary flows in turbomachinery highly affect the overall efficiency and rotorstability. A prime example of such a phenomenon are leakage flows. Despite their complexity, they can often be estimated with simple semi-empirical formulae, solved with hand calculations.Such an approach is much more cost and time effective during the design process. The formula econsists of a carry-over coefficient and a discharge coefficient elements. To evaluate the leakage properly, an adequate model of the carry-over coefficient has to be developed. This paper presents how the flow conditions and the cavity geometry changes in a straight through labyrinth sea laffect the amount of leakage. The effect of the number of teeth, the gap size, the Reynolds number and the pressure ratio are considered. The data to validate the results was obtained from an in-house experiment, where a vast number of cases was tested. Additionally, the study was supported by a two-dimensional steady-state CFD study. Eleven analytical models, including both very simple as well as more sophisticated methods, were solved according to the experimental case and compared. Six different seal configurations were examined. They included straight through seals with two and three straight knives for various gap sizes.The comparison highlighted differences in the results for models – a certain group presented underestimated results. However, another group of models – presented an excellent agreement with the experimental data. Based on this study, a group of models representing the results within the 10% uncertainty band was selected.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2019, 23, 1; 61-73
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research into flows in turbine blade seals. Part II: Numerical analysis
Autorzy:
Stępień, R.
Kosowski, K.
Badur, J.
Powiązania:
https://bibliotekanauki.pl/articles/1955751.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
turbine seals
CFD calculations
experimental investigations
Opis:
3D calculations of an axial model turbine of the impulse type were performed using the FLUENT CFD code. The calculations were carried out for variants which had been measured experimentally. Special attention was paid to the pressure field in the rotor blade shroud clearance. The Multiple Reference Frame method, the Mixing Plane method and the Sliding Mesh method were applied, and meshes of different types and configurations were used for calculations. Only the Sliding Mesh technique appeared to describe non-stationary effects and pressure pulsations in the turbine flow channels and clearances. In this part of the paper, numerical analysis is described, while the comparison between the experimental and the calculated results is presented in part III.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 3; 319-327
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Remarks on aerodynamic forces in seals of turbine stages
Autorzy:
Stępień, R.
Kosowski, K.
Powiązania:
https://bibliotekanauki.pl/articles/259359.pdf
Data publikacji:
2009
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
rotor dynamics
self-excited vibrations
aerodynamic forces
blade seals
turbine shrouds
Opis:
This paper presents results of numerical examination of flow through over-shroud seals of turbine stages. Various labyrinth seals of different configurations and number of sealing teeth were considered. It was demonstrated that results of investigations of isolated seals cannot be directly used for analyzing turbine stage operation. Such approach may lead to relatively large errors in determining value of aerodynamic force and direction of its action.
Źródło:
Polish Maritime Research; 2009, S 1; 58-63
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Calculations of labyrinth seals with and without diagnostic extraction in fluid-flow machines
Autorzy:
Kaszowski, P.
Dzida, M.
Krzyślak, P.
Powiązania:
https://bibliotekanauki.pl/articles/259462.pdf
Data publikacji:
2013
Wydawca:
Politechnika Gdańska. Wydział Inżynierii Mechanicznej i Okrętownictwa
Tematy:
labyrinth seals
Fanno curve
diagnostic extraction
Opis:
Labyrinth seals are essential components of steam turbine unit constructions. Two types of labyrinth seals can be named, the first of which is the seal without diagnostic steam extraction, and the second – with extraction. The distribution of flow parameters along the packing is affected remarkably by the average seal clearance. The presence of diagnostic extraction leads to the equation system which is determinable and can be inversed to calculate the average seal clearance Si. Analysing the obtained results leads to the conclusion that the information about this parameter provides opportunities to monitor the current state of the packing in real time. The applied calculation procedure bases on the de Saint - Venant equation. The article also includes a brief description of both types of seals.
Źródło:
Polish Maritime Research; 2013, 4; 34-38
1233-2585
Pojawia się w:
Polish Maritime Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research into flows in turbine blade seals. Part I: research methods
Autorzy:
Badur, J.
Kosowski, K.
Stępień, R.
Piwowarski, M.
Powiązania:
https://bibliotekanauki.pl/articles/1955758.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
turbine seals
CFD calculations
experimental investigations
Opis:
Flows in the shroud clearance affect leakage losses and, thus, the turbine stage efficiency. However, at the same time, the distribution of pressure in the seal gaps plays an important role in the generation of the so-called "pressure forces", which may cause self-excited rotor vibrations of the aerodynamic type. Our investigations were carried out in order to show how a CFD code can cope with determining the pressure field in a rotor-blade shroud clearance. Experimental investigations of the pressure field in the shroud clearance were performed on a one-stage air model turbine of the impulse type. Measurements of pressure distribution were carried out for various rotor speeds and turbine loads. 3D calculations of flows in the model turbine were performed using the FLUENT CFD code. The calculations were carried out for the same variants which had been measured experimentally. In this part of the paper, the experimental stand and the numerical methods are described, while a detailed numerical analysis and a comparison between the experimental and the calculated results are presented in parts II and III, respectively.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 3; 309-317
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Moulting southern elephant seals, Mirounga leonina (L.) and local weather conditions, on Livingston Island, South Shetland
Autorzy:
Cruwys, Elizabeth
Davis, Pamela B.
Powiązania:
https://bibliotekanauki.pl/articles/2052696.pdf
Data publikacji:
1994
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
Antarctica
moult
southern elephant seals
Źródło:
Polish Polar Research; 1994, 15, 3-4; 135-146
0138-0338
2081-8262
Pojawia się w:
Polish Polar Research
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Research into flows in turbine blade seals. Part III: Numerical calculations versus experiment
Autorzy:
Kosowski, K.
Stępień, R.
Piwowarski, M.
Badur, J.
Powiązania:
https://bibliotekanauki.pl/articles/1955750.pdf
Data publikacji:
2003
Wydawca:
Politechnika Gdańska
Tematy:
turbine seals
CFD calculations
experimental investigations
Opis:
Experimental and theoretical investigations of the pressure field in the shroud clearance were performed on a one-stage air model turbine of the impulse type. Measurements of pressure distribution were carried out for various rotor speeds and turbine loads. 3D calculations of flows in this turbine were performed using the FLUENT CFD code. The calculations were carried out for variants which had been measured experimentally. The experimental data have been compared to theoretical results obtained with 3D codes for turbomachinery calculations. The Sliding Mesh and Multiple Reference methods have given very similar results of average values of pressure distribution and the velocity field in the shroud clearance. These results correspond to the experimental data. The pressure pulsations were determined only by the Sliding Mesh method, and these results have also been compared with the experiment. Stage flow calculations carried by the Sliding Mesh method with a structural shroud mesh and with a minimum number of 2-2.5 million cells have given a range of non-stationary pressure pulsations corresponding to the experimental data.
Źródło:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk; 2003, 7, 3; 329-336
1428-6394
Pojawia się w:
TASK Quarterly. Scientific Bulletin of Academic Computer Centre in Gdansk
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The effects of variable operational parameters on an aero engine labyrinth seals performance
Autorzy:
Szymański, A.
Dykas, S.
Majkut, M.
Strozik, M.
Powiązania:
https://bibliotekanauki.pl/articles/175364.pdf
Data publikacji:
2018
Wydawca:
Polska Akademia Nauk. Czytelnia Czasopism PAN
Tematy:
labyrinth seals
experiment
turbomachinery
gas turbine
validation
Opis:
The paper presents the accurate assessment of the amount of gas flowing through three types of aero-engine expander sealing. Structures consisting of straight-through labyrinth seals – with one, two and three fins are considered. The study deploys two independent approaches. The first one focuses on the experimental research using high-precision test section with non-rotating labyrinth seals specimen connected to a high capacity vacuum installation. Experimentally tested seals are of actual size (model to engine scale is 1:1). High accuracy hot-wire anemometry probes, and orifice plate are deployed to evaluate the flow indicators accurately, allowing for comparison of different sealing structures. The second approach uses quasi-two-dimensional axissymmetric, steady-state Reynolds averaged Navier Stokes (RANS) computations to simulate the flow field. Various meshes and turbulence models were tested, presenting capabilities as well as limitations of specific computational approaches. The experimental and computational results were compared with literature data, showing a good agreement regarding overall trends, yet underlining some local discrepancies. This paper brings two significant findings. The 2D RANS methods tend to overestimate the leakage when compared with experimental results, and the difference is more significant for advanced arrangements. There is a notable difference between the performance of labyrinth seal with one fin and structure with two and three fins. In some operational areas, one-finned seal performs better than more advanced ones, reducing the leakage more effectively. This feature of one finned seal is not intuitive, as one would expect it to perform worse than a seal with two or three fins.
Źródło:
Transactions of the Institute of Fluid-Flow Machinery; 2018, 140; 83-104
0079-3205
Pojawia się w:
Transactions of the Institute of Fluid-Flow Machinery
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 161

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