Applied Mechanics and Materials Vol. 630

Abstract: The article reviews some questions regarding replaceable hydraulic parts (RHP) for pumps with spiral volute. A range of optimal pump parameters achievable using RHP is considered.

Abstract: The widely known fact that the parameters of many pumps are not correspond to systems characteristics which either changed in time or initially were evaluated incorrectly. In this report the main reasons of pumps operation beyond the operation range are presented. Influence of such operation on Life cycle cost. The real cases of inefficient and unreliable pump operation are presented in report. Also the results of retrofitting of pump station are presented.

Abstract: The article describes design features of sectional BB4 and double case BB5 pumps according to the API 610 requirements applied in water injection systems in order to maintain the reservoir pressure during oil production. The pumps considered are CNSp240-1422 and CNSDp240-1422 produced by HMS Group. Design optimization of casing parts is conducted by means of Finite Element Analysis in order to minimize the mass. The optimization criteria are a static strength and stiffness, and the corresponding results of strength calculation are presented.

Abstract: The influence of pumping unit’s elements on the overall energyefficiency of its work is viewed in the article. The areas of pumping unit’s operation effectiveness are identified and evaluated within the field of his QH characteristics and efficiency of its use in real technological process. The methodology of pumping unit’s operation evaluation in different modes through indicators of unit electrical energy consumption is developed.

Abstract: Current fluid film seal/bearing pressure numerical solutions taking into account both circumferential and axial lubricant flows are not in wide spread use. The most common method is to solve a two dimensional finite element method of Reynolds equation. However, this type of solution often leads to a long computer solution times when employed in an advanced seal/bearing code. A new approximate solution of Reynolds equation for oil seal or bearing flows is proposed in this paper which includes the axial flow modeling. The objective is achieved by means of an axial approximation that can be used to develop a one dimensional centerline circumferential pressure finite element solution to Reynolds equation. Optimization of the parameters associated with the approximate solution parameters is shown. Example seal/bearing pressure and load capacity calculations are presented and the solution verified by comparison with a full finite element 2-D solution. Also, the method of calculating the axial and circumferential lubricant flows as well as axial and circumferential power losses are presented and validated.

Abstract: The paper examines the issues of improving the rotor units by means of using support units with actively changeable characteristics. An overview of the known solutions related to the use of active bearings in various types of turbomachinery is provided. A closer look is given at the design and features of active radial bearings, the main elements of which are fluid film bearings. The results of mathematical modeling of active hybrid bearings are presented. The prospects of the use of this type of supports to improve the dynamic characteristics of rotating machinery, including reducing vibrations caused by various factors, are analyzed. Promising directions of development of active bearings are considered, which primarily involves the modification of system components and rotor motion control system algorithms, including intelligent technologies and artificial intelligence methods.

Abstract: Reliability of rotating machinery is determined to a considerable degree by the bearing units. For several applications the requirements in rotation speed, bearing load and maximal vibration level are so extreme that neither rolling-element bearings nor fluid-film bearings could provide necessary performance characteristics during all regimes of operation. Hybrid bearings, which are a combination of rolling-element and fluid-film bearings, can improve performance characteristics and reliability of the rotor-bearing systems. The aim of this work is to analyze the advantages and disadvantages of the hybrid bearings. Known real applications of hybrid bearings are discussed. Analysis shows that depending on the application different hybrid bearing types could improve dynamic characteristics and life time of the bearing unit, increase load capacity and DN limit of the rolling-element bearing.

Abstract: The paper investigates the two-dimensional flow of an incompressible viscous fluid of complex rheology in the gap between two cylinders with respect to fluid friction bearings. The viscosity of the fluid is defined as a physical quantity field, satisfying the criterion of minimum friction loss approximated as a function of shear-strain rate and pressure. The resulting function is used to calculate the carrying capacity and the friction torque in the bearing. Computer experiment resulted in showing the effect of friction loss lowering due to considering complex rheology of lubricating material.

Abstract: Design faults, imperfect manufacturing processes, change of technological operating modes of the turbocompressors in gas, petroleum, chemical and petrochemical industry cause axial rotor shifts. Therefore, the task of manufacturing the high-efficient and reliable thrust bearings is important nowadays along with effective rotor balancing, methods of axial forces calculation considering possible operating modes, improvement of static electricity elimination system, protective and monitoring systems of the axial shift. Effective methods for increasing the bearing capacity of thrust bearings, applied by TRIZ Ltd, have been studied in the report. The accepted and realized on the operating equipment solutions have enabled to increase the bearing capacity of thrust bearings significantly and to reduce oil consumption ratio, keeping down location dimensions to the equipment.

Abstract: 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.