Prediction of the Operating Temperature of Thrust Bearings

1981 ◽  
Vol 103 (1) ◽  
pp. 97-106 ◽  
Author(s):  
J. H. Vohr
Keyword(s):  
Heat Balance ◽  
Laboratory Tests ◽  
Operating Temperature ◽  
Field Measurements ◽  
Operating Conditions ◽  
Thrust Bearings ◽  
Pressure Distributions ◽  
Lubricant Flow ◽  
Wide Range ◽  
Balance Analysis

An analytical method is described for predicting the operating temperature of thrust bearings of the size and speed typically found in large vertical machinery. The method involves evaluating the various mechanisms by which heat is transferred from the bearing and balancing this heat loss against the calculated heat generated by viscous shearing. This heat balance analysis is combined with a comprehensive bearing computer program which evaluates bearing pressure distributions, bearing pad deflection, lubricant flow and lubricant temperature rise within the bearing film. Predicted bearing operating temperatures show excellent agreement with laboratory tests and with field measurements over a wide range of bearing sizes and operating conditions.

scholarly journals Flux-Reducing Tendency of Pd-Based Membranes Employed in Butane Dehydrogenation Processes

Membranes ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 291 ◽  
Author(s):  
Thijs A. Peters ◽  
Marit Stange ◽  
Rune Bredesen
Keyword(s):  
Competitive Adsorption ◽  
Prolonged Exposure ◽  
Hydrogen Permeation ◽  
State Of The Art ◽  
Operating Temperature ◽  
Operating Conditions ◽  
Maximum Temperature ◽  
Hydrogen Flux ◽  
Membrane Performance ◽  
Wide Range

We report on the effect of butane and butylene on hydrogen permeation through thin state-of-the-art Pd–Ag alloy membranes. A wide range of operating conditions, such as temperature (200–450 °C) and H2/butylene (or butane) ratio (0.5–3), on the flux-reducing tendency were investigated. In addition, the behavior of membrane performance during prolonged exposure to butylene was evaluated. In the presence of butane, the flux-reducing tendency was found to be limited up to the maximum temperature investigated, 450 °C. Compared to butane, the flux-reducing tendency in the presence of butylene was severe. At 400 °C and 20% butylene, the flux decreases by ~85% after 3 h of exposure but depends on temperature and the H2/butylene ratio. In terms of operating temperature, an optimal performance was found at 250–300 °C with respect to obtaining the highest absolute hydrogen flux in the presence of butylene. At lower temperatures, the competitive adsorption of butylene over hydrogen accounts for a large initial flux penalty.

Oil flow in plain steadily loaded journal bearings: Realistic predictions using rapid techniques

1998 ◽  
Vol 212 (6) ◽  
pp. 413-425 ◽  
Author(s):  
F. A. Martin
Keyword(s):  
Journal Bearings ◽  
Hydrodynamic Flow ◽  
Operating Conditions ◽  
Flow Data ◽  
Prediction Equations ◽  
Specific Flow ◽  
Flow Equations ◽  
Flow Prediction ◽  
Lubricant Flow ◽  
Wide Range

The aim of the paper is to produce a rapid calculation method for predicting lubricant flow in plain cylindrical journal bearings. Lubricant flow data, already available from rigorous solutions considering the effect of film reformation, are used together with experimental evidence to develop unique graphical aids and flow prediction equations. These equations, although developed from specific flow data, are of a general form and therefore will be applicable to a wide range of different bearing operating conditions. Graphical aids, from which the flow equations are derived, give normalized actual flow as a function of normalized hydrodynamic flow for different groove geometries. The main input parameters, namely a hydrodynamic flow term Qh and a feed pressure flow term Qp, are easy to derive and have been in common use in bearing design techniques over many decades. The new design aids, in chart and equation form, give realistic flow predictions for bearings with an oil hole, a groove opposite the load line, an axial groove at the maximum film thickness position and the commonly used case of a bearing with two axial grooves. The flow prediction equations are supported by experimental data.

scholarly journals Investigations on Oil Flow Rates Projected on the Casing Walls by Splashed Lubricated Gears

2012 ◽  
Vol 2012 ◽  
pp. 1-7 ◽  
Author(s):  
G. Leprince ◽  
C. Changenet ◽  
F. Ville ◽  
P. Velex
Keyword(s):  
Spur Gear ◽  
Operating Conditions ◽  
Test Rig ◽  
Variable Size ◽  
Flow Measurements ◽  
Flow Rates ◽  
Lubricant Flow ◽  
Wide Range ◽  
Oil Flow ◽  
Set Up

In order to investigate the oil projected by gears rotating in an oil bath, a test rig has been set up in which the quantity of lubricant splashed at several locations on the casing walls can be measured. An oblong-shaped window of variable size is connected to a tank for flow measurements, and the system can be placed at several locations. A series of formulae have been deduced using dimensional analysis which can predict the lubricant flow rate generated by one spur gear or one disk at various places on the casing. These results have been experimentally validated over a wide range of operating conditions (rotational speed, geometry, immersion depth, etc.).

Theoretical Flow-Models for Externally Pressurized Gas Bearings

1969 ◽  
Vol 91 (1) ◽  
pp. 181-193 ◽  
Author(s):  
H. Mori ◽  
Y. Miyamatsu
Keyword(s):  
Shock Wave ◽  
Load Capacity ◽  
Operating Conditions ◽  
Gas Bearings ◽  
Flow Models ◽  
Thrust Bearings ◽  
Pressure Distributions ◽  
In Series ◽  
Pressure Changes ◽  
Wide Operating

In order to make clear the characteristics of externally pressurized gas bearings, several mathematical flow-models are constructed by making proper chains of fundamental and elemental flow-patterns and pressure changes for circular thrust bearings with single central supply hole. The suggested flow-models, which are the combination of rather simple elements to make the mathematical analysis easy, are quite effective to explain the pressure distributions, the load capacity, and the rate of flow observed experimentally over wide operating conditions. And also, these flow-models make it possible to understand the effects of the inherent compensation, the so-called restrictions in series and the occurrence of shock wave.

scholarly journals Thermal Analysis of Direct Liquid-Immersed Solar Receiver for High Concentrating Photovoltaic System

2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Xinyue Han ◽  
Qian Wang ◽  
Jun Zheng ◽  
Jian Qu
Keyword(s):  
Solar Cells ◽  
Conversion Efficiency ◽  
Flow Rate ◽  
Triple Junction ◽  
Concentration Factor ◽  
Operating Temperature ◽  
Operating Conditions ◽  
Dense Array ◽  
Wide Range ◽  
Solar Receiver

Concentrator solar cells that operate at high solar concentration level must be cooled. In this paper, direct liquid immersion cooling of triple-junction solar cells (InGaP/InGaAs/Ge) is proposed as a heat dissipation solution for dense-array high concentrating photovoltaic (HCPV) systems. The advantages of triple-junction CPV cells immersed in a circulating dielectric liquid and dish HCPV technology are integrated into a CPV system to improve the system electrical conversion efficiency. An analytical model for the direct liquid-immersed solar receiver with triple-junction CPV cells is presented. The main outputs of the model are the components temperatures of the receiver and the system electrical efficiency. The influence of concentration factor, mass flow rate, and inlet liquid temperature on the operating temperature of the triple-junction CPV cells and the system electrical conversion efficiency are discussed. It is shown that the system electrical conversion efficiency is very high for a wide range of operating conditions. The three operating parameters have a major effect on the operating temperature of the triple-junction CPV cells and, by extension, system output power. The flow rate selection should match concentration factor to keep the triple-junction CPV cells temperature lower and increase the electrical conversion efficiency of the dense-array HCPV system.

Biological Removal of Chlorate from Bleaching Plant Effluent

1994 ◽  
Vol 29 (5-6) ◽  
pp. 365-372 ◽  
Author(s):  
Åsa Malmqvist ◽  
Thomas Welander
Keyword(s):  
Process Design ◽  
Laboratory Tests ◽  
Large Scale ◽  
Pilot Scale ◽  
Operating Conditions ◽  
Process Efficiency ◽  
Laboratory System ◽  
Loading Capacity ◽  
Wide Range ◽  
Suspended Carrier

Biological chlorate removal was studied on a laboratory and a pilot scale with the aim of optimizing process design and operating conditions with respect to process efficiency, stability and economy. The results showed a suspended-carrier biofilm process design to be suitable for biological chlorate removal. In the laboratory tests, at pH 7 and 37°C, a complete removal of chlorate could be maintained at hydraulic retention times (HRTs) as short as 24 min. A longer HRT (1.5 h) was required for complete chlorate removal in the pilot test, due to a lower degree of filling with carrier material (25% versus 50% of the reactor volume), higher process temperature, and leakage of oxygen into the process. However, it is assumed that the loading capacity of a large-scale process would approach that of the laboratory system if the operating conditions were the same. Laboratory tests showed chlorate reduction to be possible within a wide range of pH values and temperatures, although the process stability and loading capacity were strongly affected by changes in these parameters. The results of the laboratory and pilot scale studies, using a suspended-carrier process design, show biological treatment to be an economically viable and efficient process for the removal of chlorate from bleaching plant effluents.

Analysis of the Steady-State Multiplicity Behavior for Polystyrene Production in the CSTR

2017 ◽  
Vol 12 (4) ◽  
Author(s):  
Sang Thanh Nguyen ◽  
Ngoc Ha Hoang ◽  
Mohamed Azlan Hussain
Keyword(s):  
Heat Balance ◽  
Phase Plane ◽  
Volumetric Flow Rate ◽  
Operating Conditions ◽  
Continuous Stirred Tank Reactor ◽  
Styrene Polymerization ◽  
Wide Range ◽  
Continuous Stirred Tank ◽  
State Multiplicity ◽  
Bifurcation Behavior

Abstract The work proposes two different approaches where the first one is based on the tools of the system theory and the other is strongly related to the principle of heat balance, in order to analyze the abnormal phenomena of the continuous styrene polymerization reactors, i. e. the multiplicity behavior in the wide range of operating conditions. More precisely, the multiplicity behavior of polystyrene production in a continuous stirred tank reactor (CSTR) is carried out by the numerical simulations through the Van Heerden diagram and the phase plane. Furthermore, the bifurcation diagrams in terms of two different inputs including jacket temperature and volumetric flow rate of initiator predict the appearance of multiplicity behavior as well as the saddle-node bifurcation points. The results, firstly, verify that the multiplicity behavior of the system appears under considered operating conditions. Secondly, the analysis of bifurcation behavior gives the theoretical prediction of multiplicity behavior once the operating conditions vary due to the soft constraints or the effect of noise and disturbance.

Multiphysics Modeling of a Tilting Pad Thrust Bearing: Comparison Between White Metal and Polymeric Layered Pads

2011 ◽  
Author(s):  
R. Ricci ◽  
S. Chatterton ◽  
P. Pennacchi ◽  
A. Vania
Keyword(s):  
Load Capacity ◽  
Vertical Axis ◽  
Operating Conditions ◽  
Standard Size ◽  
White Metal ◽  
Oil Film ◽  
Thrust Bearings ◽  
Pressure Distributions ◽  
Tilting Pad ◽  
Polymeric Layer

Oil-film tilting pad thrust bearings are mainly used in supporting the high axial load of the turbine shaft in vertical hydroelectric units or smaller axial loads of turbo machines. The trend for these applications is to replace the white metal with a polymeric material layer such as PTFE or PEEK, improving the bearing performances and extending its operating conditions. This leads to a reduction of the bearing overall dimensions as a consequence of the load capacity increase. Apart the friction and the resistance to chemical attacks properties of the polymeric layer, the main cause on the improved performances of the bearing is the compliance of the pad layer. In particular the polymeric layer reduces the typical pad crowning allowing a more uniform pressure distribution over the pad and a reduction of its maximum value with respect to Babbitt metal pads. Therefore, the design of layered pad requires a deeper investigation such as thermoelastohydrodynamic (TEHD) analyses, including oilthermal effects and bearing thermal deformation. In the paper, the performance of Babbitt metal and polymeric layered pads of standard size offset-pivoted tilting pad thrust bearings of vertical axis units are compared using a multiphysics software able to manage simultaneously the mechanical, the thermal and the fluid problems. Layer and pad deformation, temperature and pressure distributions, and oil-film thickness have been analysed for different operating conditions. The model has been validated using experimental data available in literature.

Dynamic Structural Properties of Compliant Foil Thrust Bearings—Comparison Between Experimental and Theoretical Results

1994 ◽  
Vol 116 (1) ◽  
pp. 70-75 ◽  
Author(s):  
C.-P. Roger Ku
Keyword(s):  
Dynamic Characteristics ◽  
High Performance ◽  
Operating Conditions ◽  
Design Parameters ◽  
Static Loads ◽  
Thrust Bearings ◽  
Equivalent Damping ◽  
Foil Bearings ◽  
Compliant Surface ◽  
Wide Range

This paper describes an experimental investigation into the dynamic characteristics of corrugated foil (bump foil) strips used in compliant surface foil thrust bearings. This study provided the first opportunity to quantify the dynamic structural stiffness and equivalent damping coefficients of bump foil strips for a wide range of operating conditions. The experimental data were compared to results obtained by a theoretical model developed earlier. The effects of bearing design parameters, such as static loads, dynamic displacement amplitudes, bump configurations, pivot locations, surface coatings, and lubricant were also evaluated. An understanding of the dynamic characteristics of bump foil strips resulting from this work offers designers a means for enhancing the design of high-performance compliant foil bearings.

High-Speed Performance of Tapered Roller Thrust Bearings With Various Lubricating Systems

1970 ◽  
Vol 92 (1) ◽  
pp. 97-101
Author(s):  
V. V. Naik ◽  
E. L. Keim ◽  
H. R. Neifert
Keyword(s):  
High Speed ◽  
Operating Temperature ◽  
Operating Conditions ◽  
Inlet Temperature ◽  
Flow Rates ◽  
Thrust Bearings ◽  
Oil Flow ◽  
Speed Performance ◽  
Tapered Roller ◽  
Lubricant Viscosity

Using high oil-flow rates, 6-in-bore tapered roller thrust bearings were operated in a speed range of 3600 fpm to 10800 fpm with loads up to 70,000 lb. Bearing operating temperature is considered to be the principal criterion of operation. The effect of lubricating systems, speed, load, oil-flow rates, lubricant viscosity, and oil-inlet temperature on the operating temperature is demonstrated. The test-rig results are generalized by means of dimensional analysis enabling the designer to predict operating temperature for various operating conditions of speed, load, oil-flow rates, and oil-inlet viscosity.

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