Temat: oil flow - Katalog OPAC zbiorów

Skocz do pozycji: 1.

Tytuł:: Pressure in slide journal plane bearing by laminar unsteady oil flow
Autorzy:: Krasowski, P.
Powiązania:: https://bibliotekanauki.pl/articles/247887.pdf
Data publikacji:: 2007
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: journal plane bearing
lubrication
unsteady laminar oil flow
pressure distribution
Opis:: This paper shows results of numerical solutions a modified Reynolds equation for laminar unsteady oil flow in slide journal plane bearing gap. It shows a preliminary analysis of pressure distribution change in the bearing by laminar, unsteady lubrication caused by velocity perturbations of oil flow in the longitudinal direction of a bearing. Described effect can be used as an example of modelling the bearing friction node operations in reciprocating movement during exploitation of engines and machines. Plane crossbar journal bearing occur in ship combustion engine as a crosshead bearing. During modelling crossbar bearing operations in combustion engines, bearing movement perturbations from engine vertical vibrations causes velocity flow perturbations of lubricating oil on the bearing race and on the bearing slider in the longitudinal direction. Engine forced vertical vibrations frequency and crankshaft forced torsional vibrations is determined by shaft rotational speed, engine cylinder number and by engine type. This solution example applies to isothermal bearing model with infinity length. Lubricating oil used in this model has Newtonian properties and dynamic viscosity in dependence on pressure. Results are presented in the dimensionless hydrodynamicpressure diagrams.
Źródło:: Journal of KONES; 2007, 14, 3; 297-303
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Capacity forces in slide journal plane bearing by laminar unsteady lubrication
Autorzy:: Krasowski, P.
Powiązania:: https://bibliotekanauki.pl/articles/247548.pdf
Data publikacji:: 2008
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: journal plane bearing
lubrication
unsteady laminar oil flow
pressure distribution
capacity forces
Opis:: This paper shows results of numerical solutions an modified Reynolds equations for laminar unsteady oil flow in slide journal bearing with planar linear gap. Discussed case of the solution to the Reynolds equation for the unsteady laminar Newtonian flow of lubricating factor allows initial estimation of hydrodynamic pressure distribution and its capacity as a basic operational parameter of the slide bearing. Unsteady axial velocity perturbation on the race surface and slide has influence on the hydrodynamic pressure distribution of the capacity of the lubricated gap. Pressure changes in the bearing are seasonal and equal to the lasting period of velocity perturbation. The level of changes and its nature depends on the kind of perturbation. This solution example applies to isothermal bearing model with infinity length. Lubricating oil used in this model has Newtonian properties and dynamic viscosity in dependence on pressure. It shows a preliminary analysis change of capacity forces in the bearing by laminar, unsteady lubrication caused by velocity perturbations of oil flow in the longitudinal direction of a bearing. Described effect can be used as an example of modeling the bearing friction node operations in reciprocating movement during exploitation of engines and machines. Plane crossbar journal bearing occur in ship combustion engine as a crosshead bearing. Results are presented in the dimensionless hydrodynamic pressure and capacity force diagrams.
Źródło:: Journal of KONES; 2008, 15, 3; 245-252
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: Experimental and computational studies of stall on a helicopter rotor airfoil
Autorzy:: Surmacz, K.
Powiązania:: https://bibliotekanauki.pl/articles/246413.pdf
Data publikacji:: 2016
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: 3D flow
CFD
wind tunnel test
oil visualization
stall phenomenon
Opis:: In the case of forward flight of a helicopter, the flow field around rotating blades of a rotor is highly threedimensional and very complex. Helicopter blades work across a wide range of angles of attack and airspeed. The stall occurs on the retreating blade in forward flight and causes dissymmetry of lift on a rotor disc. The investigation of the stall phenomenon has been performed using experimental and computational methods. Experimental analysis was made at the Ohio State University 6’’x 22’’ unsteady transonic wind tunnel. Research in the wind tunnel was performed using two methods: oil visualization (over a wide range of alpha and Ma) and pressure measurements. Computational part of the research has been done using Computational Fluid Dynamics tool. 2- and 3-dimensional calculations performed using ANSYS FLUENT software. In both experimental and computational cases, the 3D flow around a section of a rotor blade based on the SSC-A09 airfoil was analysed. The test article of the research was a section, which was located in the tip region of the main rotor blade of UH-60M Black Hawk helicopter. The research was conducted for a wide range of angles of attack and at several velocities. The most interesting part of the analysis concerned on unsteady flow conditions corresponding to stall.
Źródło:: Journal of KONES; 2016, 23, 3; 511-517
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: CFD analysis of non-Newtonian and non-isothermal lubrication of hydrodynamic conical bearing
Autorzy:: Czaban, A.
Powiązania:: https://bibliotekanauki.pl/articles/243876.pdf
Data publikacji:: 2014
Wydawca:: Instytut Techniczny Wojsk Lotniczych
Tematy:: conical bearing
hydrodynamic lubrication
CFD simulation
non-Newtonian oil
non-isothermal flow
pressure distribution
Opis:: In this work is shown the result of CFD simulation of hydrodynamic conical bearing lubrication with consideration of non-isothermal oil flow in a bearing lubrication gap and also with assumption, that oil has non- Newtonian properties. The determination of hydrodynamic pressure distribution in bearing gap was carried out by using the commercial CFD software ANSYS Academic Research for fluid flow phenomenon (Fluent). Calculations were performed for bearings without misalignment, i.e. where the cone generating line of bearing shaft is parallel to the cone generating line of bearing sleeve. The Ostwald-de Waele model for non-Newtonian fluids was adopted in this simulation. The coefficients of Ostwald-de Waele relationship were determined by application of the least squares approximation method and fitting curves described by this model to the experimental data, obtained for some motor oils, presented in previous work. The calculated hydrodynamic pressure distributions were compared with the data obtained for corresponding bearings, but assuming that the flow in the bearing lubrication gap is isothermal. Some other simplifying assumptions are: a steady-state operating conditions of a bearing, incompressible flow of lubricating oil, no slip on bearing surfaces, pressure on the side surfaces of bearing gap is equal to atmospheric pressure. This paper presents results for bearings with different rotational speeds and of different bearing gap heights.
Źródło:: Journal of KONES; 2014, 21, 4; 49-56
1231-4005
2354-0133
Pojawia się w:: Journal of KONES
Dostawca treści:: Biblioteka Nauki

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