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EN
In this paper, a multilobe conical bearing is analyzed. A lubricant modelled by a couple stress fluid flows In the bearing clearance . The Galerkin method is used to determine the mechanical parameters of multilobe journal bearings. An example of a two-lobe conical bearing is discussed in detail. The inertia of the flowing lubricant is taken into account in the analysis. It has been found that the increase of the couple stress generates an increase the pressure in the clearance.
EN
The flow of a couple-stress lubricant in a clearance of a curvilinear thrust hydrostatic bearing with impermeable walls is considered. The flow in the bearing clearance is considered with inertia forces. The equations of motion are solved by an averaged inertia method. As a result, the formulae for pressure distributions without and with inertia effects were obtained. Radial thrust bearings and spherical bearings are discussed as numerical examples. It is shown that inertia effects influence the bearing performance considerably.
PL
Rozważania teoretyczne, a także większość badań eksperymentalnych, odnoszących się do łożysk ślizgowych dotyczy przypadku idealnie gładkich powierzchni; w rzeczywistości powierzchnie łożysk ślizgowych są zawsze chropowate. Bezwładność oleju smarnego przepływającego w szczelinie hydrostatycznego łożyska wzdłużnego ma istotny wpływ na parametry mechaniczne łożyska. W pracy przedstawiono równanie Reynoldsa uwzględniające zarówno bezwładność przepływającego środka smarnego jak i chropowatość powierzchni roboczych łożyska hydrostatycznego wzdłużnego; w wyniku rozwiązania równania Reynoldsa określono parametry mechaniczne łożyska.
4
Content available remote Inertia effects in a porous squeeze film bearing lubricated by a Bingham fluid
EN
The influence of inertia and wall porosity on the pressure distribution in a curvilinear squeeze film bearing lubricated by a viscoplastic fluid of a Bingham type is considered. The general consideration on the flow of the viscoplastic fluid in a bearing clearance and in a porous layer are presented. Using the Morgan-Cameron approximation and an averaged inertia method the modified Reynolds equation for the curvilinear thrust bearing is given. The solution of this equation for the case of the squeeze film bearing is presented. As a result one obtains a formula expressing the pressure distribution. The example of a squeeze film between parallel disks is discussed in detail.
EN
Many electrorheological fluids (ERFs) as fluids with micro-structure demonstrate viscoplastic behaviours. Rheological measurements indicate that the flows of these fluids may be modelled as the flows of a Bingham fluid. Our concern in the paper is to examine the pressurized laminar flow of an ERF of a Bingham type in a narrow clearance between to fixed surfaces of revolution. In order to solve this problem the boundary layer equations are used. The Reynolds number effects (the effects of inertia forces) on pressure distribution are examined by using the averaged inertia method. Numerical examples of externally pressurized flows in the clearance between parallel disks and concentric spherical surfaces are presented.
EN
In many practical situations fluids are normally blended with additives (viscosity index improvers, viscosity thickeners, viscosity thinners) due to which they show pseudoplastic and dilatant nature which can be modelled as cubic stress model (Rabinowitsch model). The cubic stress model for pseudoplastic fluids is adopted because Wada and Hayashi have shown that the theoretical results with this model are in good agreement with the experimental results. The present theoretical analysis is to investigate the pseudoplastic effect along with the effect of rotational inertia on the pressure distribution, frictional torque and fluid flow rate of externally pressurised flow in narrow clearance between two curvilinear surfaces of revolution. The expression for pressure has been derived using energy integral approach. To analyse and discuss the effects of pseudoplasticity and fluid inertia on the pressure distribution, fluid flow rate and frictional torque, the examples of externally pressurised flow in the clearance between parallel disks and concentric spherical surfaces have been considered.
EN
In the paper the influence of inertia forces on the pressure distribution and load-carrying capacity of a thrust bearing with curvilinear working surfaces is discussed. The equations of motion of a pseudo-plastic fluid of Rotem-Shinnar, including inertia term of a circumferential flow, are used to derive the modified Reynolds equation. As a result of an analytical solution of the modified Reynolds equation the formulae for the bearing performance are obtained. Step and spherical bearings are considered as examples.
8
Content available remote Inertia effects in a curvilinear thrust hydrostatic bearing with a porous pad
EN
The flow of a Newtonian lubricant in a clearance of a curvilinear thrust hydrostatic bearing with one porous wall is considered. The bearing is modelled by two curvilinear smooth surfaces and the porous wall is adhered to the curve non-porous surface. The flow in the bearing clearance is considered with inertia forces and the Navier-Stokes and Poisson equations are uncoupled by using the Morgan-Cameron approximation. The equations of motion are solved by an averaged inertia method. Step and spherical bearings are discussed as examples. It shown that the inertia effects influence the bearing performance considerably.
EN
The flow of a power-law lubricant in a clearance of a curvilinear thrust hydrostatic bearing with impermeable walls is considered. The bearing is modelled by two curvilinear smooth surfaces. The lubricant flow in the bearing clearance is considered with inertia forces. The equations of motion for power-law fluid (similar to the boundary layer equations) are solved by an averaged inertia method. Step and spherical bearing are discussed as examples. It is shown that the inertia effects influence the bearing performance considerably.
10
Content available remote Inertia effects in a curvilinear thrust hydrostatic bearing
EN
The flow of a Newtonian lubricant in a clearance of a curvilinear thrust hydrostatic bearing with impermeable walls is considered. The flow in the bearing clearance is considered with inertia forces. The equations of motion are solved by an averaged inertia method. A step bearing and a spherical bearing are discussed as examples. It is shown that inertia effects influence the bearing performance considerably.
EN
The flow of a power-law lubricant in a squeeze film bearing with one porous pad is considered. The bearing is modelled by two curvilinear surfaces and the porous pad is adhered to the curved non-porous surface. The flow in the bearing clearance is considered with inertia and the Navier-Stokes and Poisson equations are uncoupled by using the Morgan-Cameron approximation. Using the averaged inertia method the closed-form solution is obtained. A step bearing is discussed as an example.
PL
Rozważono przepływ potęgowego środka smarnego w wyciskanym filmie łożyska z porowatą wkładką. Łożysko jest modelowane dwiema krzywoliniowymi powierzchniami, a porowata wkładka przylega do zakrzywionej nieprzepuszczalnej powierzchni. Przepływ w szczelinie łożyska jest rozważony z uwzględnieniem bezwładności, a równania Naviera-Stokesa i Poissona rozwiązano wykorzystując przybliżenie Morgana-Camerona. Stosując metodę uśrednionej bezwładności uzyskano formuły określające ciśnienie i siłę nośną. Jako przykład rozważono łożysko płytkowe.
EN
In the paper, the influence of inertial effects on pressure distribution in a thrust bearing having the curvilinear outline of working spaces is discussed. Quasi-linear equations of motion incorporating inertia elements of circumferential flow of a pseudo-elastic fluid are used to solve the problem. An analytical solution of the equations of motion rendered it possible to work out a formula for the determination of pressure distribution. A flat and spherical thrust bearing is considered as an example.
PL
W artykule autorzy omawiają wpływ efektów bezwładnościowych na rozkład ciśnienia w łożysku wzdłużnym o krzywoliniowym zarysie powierzchni roboczych. Do rozwiązania zagadnienia użyto quasi-liniowych równań ruchu, zawierających składniki bezwładności przepływu obwodowego płynu pseudoplastycznego. Analityczne rozwiązania równań ruchu pozwoliły na wyznaczenie formuły określającej rozkład ciśnienia. Jako przykład rozpatrzono łożysko wzdłużne płaskie i kuliste.
13
Content available remote Flow of a couple-stress fluid in a curvilinear thrust bearing with one porous pad
EN
The flow of a couple stress fluid in the clearance of a curvilinear bearing with a porous pad is considered. The porous pad is connected with the upper impermeable rotating surface which approaches the lower fixed bearing surface. The Reynolds and Poisson equations are uncoupled by using the Morgan-Cameron approximation and a closed-form solution is obtained. As an example the bearing formed by two disks is discussed.
PL
W pracy rozważono przepływ płynu z naprężeniami momentowymi w krzywoliniowej szczelinie łożyska z porowatą wkładką. Porowata wkładka powiązana jest z górną nieprzepuszczalną wirującą powierzchnią, która zbliża się do dolnej nieruchomej powierzchni łożyska. Do rozwiązania równań Poissona oraz Reynoldsa wykorzystano przybliżenie Morgana-Camerona. Jako przykład rozpatrzono łożysko utworzone przez dwie kołowe tarcze.
EN
The flow of couple stress fluid in the clearance of a curvilinear channel with the porous pad was considered. The porous pad was connected with the upper impermeable rotating surface approaching the lower fixed channel surface. The Reynolds and Poisson equations were uncoupled using the Morgan-Cameran approximation and closed-form solution was obtained, As an example the channel formed by two disks was discussed.
EN
Inertia effects in the flow of suspension modelled as a power-law fluid in a curvilinear squeeze film channel with the porous pad were considered. The analysis was based on the assumption that the porous pad consisted of a system of capillaries of very small radii, which allowed the use of the Darcy law and the Mor-gan-Cameron approximation for the flow in the porous pad. A spherical channel was discussed as an example.
EN
The fully developed steady laminar flow of a generalized second grade fluid of a power-law type through a narrow space between two fixed surfaces of revolution, having a common axis of symmetry, is considered. One obtained the solution of this problem using the boundary layer equations expressed for axially symmetric case in a curvilinear orthogonal coordinate system connected with one of the surfaces. The method of averaging inertia and viscoelastic terms is used to find the formula expressing the pressure distribution in a clearance between fixed surfaces of revolution.
17
Content available remote Performance of a thrust bearing lubricated by a Bingham ferromagnetic lubricant
EN
The effects of centrifugal inertia forces on the pressure distribution in the curvilinear thrust bearing lubricated by a ferromagnetic viscoplastic lubricant of a Bingham type are examined. The examples of flows in the bearing modelled by and two concentric spheres are considered. The results obtained show that ferrofluid inertia forces and magnetization have significant effects on the pressure distributions and on the load-capacity.
18
EN
The effects of centrifugal inertia forces on the pressure distribution in the curvilinear thrust bearing lubricated by a power-law ferrofluid are examined. The examples of flows in the bearings modelled by two disks and two concentric spheres are considered. The results obtained show that ferrofluid inertia forces and magnetization have significant effects on the pressure distributions.
EN
The steady laminar flow of a generalized second grade fluid of a power-law type through a narrow space between two fixed surfaces of revolution, having a common axis of symmetry, is considered. To solve this problem the boundary layer equations are used and expressed for axially symmetric case in a curvilinear orthogonal coordinate system connected with one of the surfaces. The method of averaging inertia and viscoelastic terms is used to solve the formula expressing the pressure distribution in a gap between fixed surfaces of revolution.
20
Content available remote Mechanical parameters of a multilobe conical bearing with ferromagnetic lubricant
EN
In this paper the authors present a solution to the problem of an inertia effect of ferromagnetic lubricant flow in a multilobe conical bearing. The problem was solved by Galerkin's method after assuming that the bearing is lubricated with an incompressible Newtonian lubricant. The general form of solutions for pressure distribution and axial load for particular cases of the bearing geometry are given
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