Abstract. The theory of fluid flow in an eccentrically deposited annulus has of great importance especially in the design of sliding bearings (axial, radial). If the geometry is more complex or shaft is deposited eccentrically, then a suitable alternative for design hydrostatic bearing is using ANSYS Fluent, which solves the general three-dimensional viscous fluid flow also in complex geometry. The problem of flow solves in the narrow gap between the cylinders in this paper, when the inner cylinder is stored with a defined eccentricity. The movement of the inner cylinder is composed of two motions (rotation, precession), i.e. rotation around its own axis and move along the circle whose radius is the size of the eccentricity. Addition the pressure gradient is considered in the axial direction. In the introductory section describes the methodology for defining of motions (rotation and precession of the inner cylinder) when the user function (UDF) is created that defines the rotation and move along the circle in C++. The above described methodology of the solution was then applied to the 3D model with a defined pressure drop when the problem was solved as a time-dependent with a time value corresponding to two turns of the internal shaft.

Abstract. This paper evaluates the influence of radial grooves in the eccentrically deposited annulus using by mathematical modeling of fluid flow through each grooves. The inner cylinder (rotor) is eccentrically deposited and its movement is composed of two movements (rotation and precession). The outer cylinder is stationary and has radial grooves. In the first phase is defined a mathematical model of the flow, which is then applied to the 3D model of narrow gap with radial grooves. In this paper are present several variants of the computational domain with regard to the number of radial grooves. Based on the results of numerical simulations are evaluated basic variables such as pressure and velocity. There are also evaluated radial force (F r ) and axial force (F a ) acting on the rotor for different boundary conditions (different speeds of rotation and precession). Subsequently, the pressure gradients (Δp) are evaluated between the radial grooves for different computational domain. Results are compared to variant of narrow gap without radial grooves. Numerical simulation is realized in the program system ANSYS Fluent.

This article is aimed to define the flow in the annulus. The shaft is deposited in a case which has at inlet and outlet recess. The rotor moves in the case. This movement can be divided into the rotation and precession. It is situation where the rotor rotates around own axis and together moves along the circle. The solution of the problem was the initiative in practice where this type of movement occurs in many components, e.g. sliding journal bearings. The fluid flows in the annulus due to the pressure gradient between inlet and outlet and together takes place rotational movement due to movement of the rotor. Between the liquid and the solid of an interaction which results in a change in the forces. The problem is solved by mathematical CFD solver ANSYS Fluent. Based on the characteristics of the problem has been defined corresponding to a mathematical model for the selected types of liquids - VG 32 mineral oil, VG 150 mineral oil and water. Individual variants of used liquids are compared with each other courses of forces acting on the rotor under the same boundary conditions.

Abstract. The current research of hydrostatic bearings and hydrostatic slide-ways is far from being over. The topic is constantly evolving, creating new geometries of the sliding bearings, developing new types of friction materials and lubricants. The control elements of hydraulic mechanisms that serve to regulation of the hydrostatic bearings tipping are still in progress. Almost every application has different requirements for the bearings, whether in terms of loading capacity, speed rotation, and also the price. All these aspects should be included in the design of hydrostatic thrust bearings. Thanks to great advances in the development of computer technology and software for numerical modelling, we can simulate real movement of viscous fluids. To create a numerical model of hydrostatic thrust bearing, Ansys Fluent 14.0 software package has been applied. The article describes the basic methods of numerical modelling of the given problem and evaluates the pressure field and the loading capacity of annular multi-recess hydrostatic thrust bearing and its dependence on the change in static pressure.

Abstract. The hydraulic circuit, through which the mineral oil is brought, is an important part of hydrostatic bearings. The annular hydrostatic thrust bearing consists of two sliding plates divided by a layer of mineral oil. In the lower plate, there are oil grooves which distribute the liquid between the sliding areas. The hydraulic circuit is made of two basic parts: the energy source and the controlling part. The hydraulic pump, which brings the liquid into the sliding bearing, is the source of the pressure energy. The sliding bearing is weighted down by axial force, which can be changed during the process. That´s why in front of the particular oil grooves control components adjusting pressure and flow size are located. This paper deals with a project of a hydraulic circuit for regulation of fluid layer in the annular hydrostatic thrust bearing and the testing equipment for measuring its physical properties. It will include the issue of measuring loading capacity and height of the fluid layer in the annular hydrostatic thrust bearing.