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Wyszukujesz frazę "friction force" wg kryterium: Temat


Wyświetlanie 1-3 z 3
Tytuł:
The friction force and friction coefficient in the journal sliding bearing ferrofluid lubricated with different concentrations of magnetic particles
Autorzy:
Frycz, M.
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/247265.pdf
Data publikacji:
2011
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
hydrodynamic pressure
capacity
friction force
friction coefficient
ferrofluid
numeric calculation
Opis:
There is an important operational parameter in the case of sliding bearings are friction forces and coefficient of friction. It depends on how much proportions of heat in the gap of the oil film from the value of the friction force. Ferrofluid lubricated sliding bearings have specific structure and are suitable only for use in specific cases. We may use them in the absence of gravity, vacuum, or in case of strong magnetic fields or radioactive. Maintenance of lubricant in the oil-gap as well as the viscosity change occurs through controlling of the external magnetic field. Change of the value of viscosity and mass forces (magnetic forces) in the equation of momentum depends on the concentration of magnetic particles and the intensity of external magnetic field. The aim of this paper is to present the influence of concentration of magnetic particles on the friction force value and coefficient of friction. The numerical calculations of friction forces and friction coefficient have been performed before setting the hydrodynamic pressure and a lift force from the Reynolds-type equation. Reynolds-type equation has been derived from basic equations, ie equations of momentum and equations of stream's continuity. There have been also used Maxwell's equations for the ferrofluid in the case of stationary magnetic field's existence. It has been assumed stationary and laminar flow of lubricant liquid and the isothermal model for lubrication of slide bearings. As the constitutive equation has been used Rivlin-Ericksen one. The cylindrical journal bearing of finite length with the smooth sleeve of whole angle of a belt has been taken into consideration. In a thin layer of oil film has been assumed constancy of the oil density with temperature changes and the independence of the oil's thermal conductivity coefficient from thermal changes. The viscosity of the oil depends mainly on the magnetic field.
Źródło:
Journal of KONES; 2011, 18, 4; 113-120
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Influence of magnetic particles concentration in ferro-oil on values of friction force and coefficient of friction of slide journal bearing
Autorzy:
Frycz, M.
Miszczak, A.
Powiązania:
https://bibliotekanauki.pl/articles/243124.pdf
Data publikacji:
2017
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
ferro-oil
dynamic viscosity
magnetic particles concentration
friction force
friction coefficient
lepkość dynamiczna
stężenie cząstek magnetycznych
siła tarcia
współczynnik tarcia
Opis:
This article has been focused on the analysis of changes in friction force as well as coefficient of friction of slide journal bearing in terms of the concentration of magnetic particles in the lubricating ferro-oil. There has been present an analytical and numerical calculation model based on experimentally determined physical quantities describing the dependence of ferro-oil’s viscosity on fundamental parameters such as temperature, pressure or external magnetic field in the paper. Numerical calculations of the dimensionless friction force as well as the dimensionless friction coefficient were performed by solving the Reynold’s type equation using the finite difference method using Mathcad 15 and own calculation procedures. The obtained results has been presented in the form of a series of graphs that take into account: the influence of external magnetic field, corrections related to the influence of pressure changes, corrections related to the influence of temperature changes and finally corrections related to non-Newtonian ferro-oil properties. An analysis of the obtained characteristics has been made so the observations and conclusions were drawn regarding optimum magnetic particle content in the ferro-oil lubricating the sliding journal bearing.
Źródło:
Journal of KONES; 2017, 24, 1; 143-150
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
The program of experimental research regarding concentration of magnetic particles Fe3 O4 in ferrofluid for slide journal bearing lubrication
Autorzy:
Miszczak, A.
Frycz, M.
Powiązania:
https://bibliotekanauki.pl/articles/246352.pdf
Data publikacji:
2010
Wydawca:
Instytut Techniczny Wojsk Lotniczych
Tematy:
hydrostatic bearings
ferrofluid
position of test bearings
measuring the force of friction
magnetic field
hydrodynamic bearings
temperature distribution
Opis:
This paper presents the project of the test stand to determine the friction force, the relative eccentricity and temperature distribution m the slide journal bearing during the lubrication with ferrofluid or classic oil. The test stand is built on the basis of TUM 25 lathe's corps. There is the shaft with a diameter of journal d = 100 mm supported on two supports attached to the lathe's body. There is a sleeve in the housing with the electromagnets installed in the centre of this shaft. The housing of sleeve is loaded bv a transverse force with hydrostatic supports (cylindrical and flat one). Measurement of friction force is made by strain gauge force sensor Friction force is measured on the body shells. At the same time is performed measurement of both sleeve and journal displacements by four inductive displacement's sensor s and four whirl-stream ones to determine the relative eccentricity and displacement of sleeve axis towards oj the shaft axis. The slide bearing is supplied bv the ferrofluid which is thermatly stabilized in ultrathermostat. In the paper is shown particular plan for experimental research. These studies are intended to demonstrate the changes of relative eccentricity and temperature distribution in the bearing. Additionally are presented the changes of friction forces caused by the bearing surfaces shape and ferrolubricant with different concentrations of magnetic particles Fe3O4. The gap of slide bearing can be affected by the external longitudinal magnetic field with different ralues of magnetic field strength. The bearing may by loaded a transverse force varying stepwise, or continuously with values from a few to several thousand Newton. A/so, the rotational velocitv of Journal can be changed stepwise, or continuously from 0 to 6000 rpm using a programmable inverter.
Źródło:
Journal of KONES; 2010, 17, 2; 321-325
1231-4005
2354-0133
Pojawia się w:
Journal of KONES
Dostawca treści:
Biblioteka Nauki
Artykuł
    Wyświetlanie 1-3 z 3

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