Fourth Paper: A New Design of Angular Contact Ball Race

1970 ◽  
Vol 185 (1) ◽  
pp. 382-393 ◽  
Author(s):  
D. J. Haines ◽  
M. J. Edmonds
Keyword(s):  
High Speed ◽  
Operating Conditions ◽  
Approximate Analysis ◽  
Full Extent ◽  
Operating Range ◽  
Contact Points ◽  
High Speeds ◽  
New Race ◽  
Outer Contact ◽  
Ball Motion

The work reported in the second and third papers revealed that under high speed operating conditions significant slide occurs at the contact points. The full extent of the present limitations became apparent in 1967 and led in that year to the new race design. In this design the balls contact the outer track at two points simultaneously instead of the conventional one point. An approximate analysis of race behaviour is presented which indicates that when the new bearing is driven from the inner track the ball motion is controlled at this track over most of the operating range. This fact and the retention of the inner, and the major outer contact positions, at points close to their static positions result in improvements in performance of up to 30 per cent at high speeds.

The Measurement and Analysis of Ball Motion in High Speed Deep Groove Ball Bearings

1975 ◽  
Vol 97 (3) ◽  
pp. 341-348 ◽  
Author(s):  
R. J. Boness ◽  
J. J. Chapman
Keyword(s):  
High Speed ◽  
Experimental Results ◽  
Complete Analysis ◽  
Ball Speed ◽  
Rolling Axis ◽  
High Speeds ◽  
Deep Groove ◽  
Wide Range ◽  
Ring Mode ◽  
Ball Motion

This paper reports on a study of ball motion, including the measurement of ball rolling axis, in deep groove bearings operating at high speeds under thrust load conditions. The technique employed relies on viewing the test bearing, operating in the conventional fixed outer ring mode, through a rotating prism which eliminates optically the gross rotation of the separator. Videotape recordings of a selected ball, distinctively marked and illuminated stroboscopically, allows a complete analysis of ball bearing kinematics. Experimental results of separator speed, ball speed and rolling axis together with separator slip, ball slip and spin velocities at both the inner and outer raceway contacts are presented for a wide range of loads and shaft speeds up to 12,000 rev/min. These results are compared with the existing theory of Jones. Discrepancies between predicted and actual ball motion are due to the assumption made by Jones in neglecting bearing element slip. A further analysis of the experimental results including both gyroscopic torques and slip based on elastohydrodynamic traction values for the test lubricant explains actual ball motion more fully.

Unsteady Measurements of Periodic Effects in a Transonic Compressor With Casing Treatments

2016 ◽  
Vol 138 (5) ◽  
Author(s):  
Christoph Brandstetter ◽  
Fabian Wartzek ◽  
Jan Werner ◽  
Heinz-Peter Schiffer ◽  
Frank Heinichen
Keyword(s):  
High Speed ◽  
Operating Conditions ◽  
Reference Case ◽  
Stall Inception ◽  
Operating Range ◽  
Transonic Compressor ◽  
High Pressure Compressor ◽  
Image Velocimetry ◽  
Blade Tip ◽  
Casing Treatments

Application of nonaxisymmetric casing treatments (CTs) can extend the operating range of a transonic compressor significantly. Recent CT designs have proven successful at achieving operating range extension without efficiency loss under design conditions. Two different CT designs were investigated on a high-speed one and a half stage test rig using extensive instrumentation. The stage setup is representative of the front stage of a modern high-pressure compressor. Results of particle image velocimetry (PIV) measurements taken in the blade tip region underneath the CT show a significantly modified flow structure compared to the smooth casing reference case. Blockage zone, secondary flow, and shock structures are affected by the CT, especially in highly throttled operating conditions. The stall inception process of the system with axial slots shows unexpected behavior, with modal activities that are not observed without CT. These activities are resolved using unsteady wall pressure (WP) and hot wire measurements.

Angular Contact Ball Bearings: Track Position at High Speeds

1969 ◽  
Vol 184 (1) ◽  
pp. 351-370
Author(s):  
K. C. Falcon ◽  
C. Andrew
Keyword(s):  
High Speed ◽  
Contact Angles ◽  
Operating Conditions ◽  
Turbine Engines ◽  
Gas Turbine Engines ◽  
Test Rig ◽  
Outer Race ◽  
High Speeds ◽  
Surface Displacements ◽  
Lubricant Flow

The track position of the balls on the outer race of an angular contact bearing of the series and size used on the main shaft of aero gas turbine engines was measured in a test rig. The test rig was capable of simulating the operating conditions of the bearing with respect to axial load, inner race speed and high lubricant flow rates. The contact angle, defined by the track position, was deduced from the measurement of sub-surface displacements in the race using a number of small transducers embedded therein. The resulting contact angles were compared with values predicted from a number of unconfirmed theories in current use. At conditions of high speed and low load the correlation is poor; an over-estimation of the cage speed, arising from the false assumption that gross ball slip does not occur, gives rise to an over-estimation of the changes of contact angles from their nominal values.

Unsteady Measurements of Periodic Effects in a Transonic Compressor With Casing Treatments

2015 ◽  
Author(s):  
Christoph Brandstetter ◽  
Fabian Wartzek ◽  
Jan Werner ◽  
Heinz-Peter Schiffer ◽  
Frank Heinichen
Keyword(s):  
High Speed ◽  
Operating Conditions ◽  
Reference Case ◽  
Stall Inception ◽  
Casing Treatment ◽  
Operating Range ◽  
Transonic Compressor ◽  
High Pressure Compressor ◽  
Blade Tip ◽  
Casing Treatments

Application of non-axisymmetric Casing Treatments (CTs) can extend the operating range of a transonic compressor significantly. Recent CT designs have proven successful at achieving operating range extension without efficiency loss under design conditions. Two different CT designs were investigated on a high-speed one and a half stage test rig using extensive instrumentation. The stage setup is representative of the front stage of a modern high-pressure compressor. Results of Particle Image Velocimetry (PIV) measurements taken in the blade tip region underneath the Casing Treatment show a significantly modified flow structure compared to the Smooth Casing reference case. Blockage zone, secondary flow and shock structures are affected by the CT, especially in highly throttled operating conditions. The stall inception process of the system with Axial Slots shows unexpected behavior, with modal activities that are not observed without CT. These activities are resolved using unsteady wall pressure and Hot Wire measurements.

Application of Lund’s Stability Analysis Program in Design of Modern Turbomachinery

2003 ◽  
Vol 125 (4) ◽  
pp. 471-476 ◽  
Author(s):  
Pranabesh De Choudhury
Keyword(s):  
Stability Analysis ◽  
High Speed ◽  
Analytical Tool ◽  
Gas Pressure ◽  
Operating Conditions ◽  
Analysis Program ◽  
Gas Density ◽  
High Speeds ◽  
Design And Manufacture

The analytical tool developed by Lund has aided in the design and manufacture of modern turbomachinery operating at relatively high speeds, under severe operating conditions, with high gas pressure, and gas density. The purpose of this paper is to show, by means of selected problems, as a practicing engineer in the design of high speed turbomachinery, how the methods developed by Lund aided in the design and problem diagnostics of such turbomachinery.

Effect of Design Changes in Railway Catenary-Pantograph Systems on Power Collection at High Speed

1968 ◽  
Vol 90 (4) ◽  
pp. 680-689
Author(s):  
R. T. Gray ◽  
S. Levy ◽  
J. A. Bain ◽  
E. J. Leclerc
Keyword(s):  
Contact Force ◽  
High Speed ◽  
Operating Conditions ◽  
Department Of Transportation ◽  
High Speeds ◽  
Design Changes ◽  
Force Variation ◽  
Suitable System ◽  
The U.S

Using a GE-635 computer program developed for the U.S. Department of Transportation, a study has been made of the effect of changes in the catenary-pantograph system on the quality of power collection at high speeds. The study explored the effect of: (a) Sag between towers, (b) pantograph spacing, (c) stiffness of the tower support, (d) damping and stiffness of the pantograph, (e) stiffness of the contact spring, (f) dropper stiffness, (g) dropper spacing. It was found that all of these have a significant effect on the constancy of the contact force between catenary and pantograph. By proper choice of system constants, the contact force variation can be substantially reduced. A basis is provided for selecting suitable system constants for a given range of operating conditions.

Application of Lund’s Stability Analysis Program in Design of Modern Turbomachinery

2001 ◽  
Author(s):  
Pranabesh De Choudhury
Keyword(s):  
Stability Analysis ◽  
High Speed ◽  
Analytical Tool ◽  
Gas Pressure ◽  
Operating Conditions ◽  
Analysis Program ◽  
Gas Density ◽  
High Speeds ◽  
Design And Manufacture

Abstract The analytical tool developed by Lund has aided in the design and manufacture of modern turbomachinery operating at relatively high speeds, under severe operating conditions, with high gas pressure, and gas density. The purpose of this paper is to show, by means of selected problems, as a practicing engineer in the design of high speed turbomachinery, how the methods developed by Lund aided in the design and problem diagnostics of such turbomachinery.

Quasi-static and dynamic analyses of thin-webbed high-speed gears: Centrifugal effect influence

2019 ◽  
Vol 233 (21-22) ◽  
pp. 7282-7291
Author(s):  
B Guilbert ◽  
P Velex ◽  
P Cutuli
Keyword(s):  
Finite Elements ◽  
High Speed ◽  
Operating Conditions ◽  
Centrifugal Effect ◽  
High Speeds ◽  
Load Distributions ◽  
Lumped Parameter ◽  
Dynamic Analyses ◽  
Gear Geometry

The objective of this paper is to analyse the effect of centrifugal effects on thin-rimmed/-webbed gears. To this end, an original hybrid gear model is used, which combines lumped parameter elements, finite elements and condensed sub-structures along with a mortar-based mesh interface aiming at coupling mismatched models. It is shown that due to gear body flexibility, centrifugal effects can strongly modify geometry and, consequently, tooth load distributions at high speeds. The possibility to counterbalance these effects by introducing profile and lead modification is investigated. It is finally shown that for the effective tooth design, both thin-rimmed gear geometry and operating conditions must be accounted for.

Motion of Unbalanced Balls in High-Speed Angular Contact Ball Bearings

1990 ◽  
Vol 112 (1) ◽  
pp. 105-110 ◽  
Author(s):  
H. Kawamura ◽  
K. Touma
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Three Dimensional ◽  
Ball Bearings ◽  
Axial Loads ◽  
Angular Contact Ball Bearing ◽  
High Speeds ◽  
Dimensional Ball ◽  
Ball Motion ◽  
Bearing Ball

This paper reports on an experimental study of the three-dimensional ball motion of an unbalanced ball in a 50-mm bore angular contact ball bearing operating at high speeds under axial loads. One bearing ball, which was unbalanced by making a small hole in it, was magnetized and the motion of the ball was determined using Hall-elements. The bearing was tested under various loads and speeds up to 12,000 rpm. The influence of unbalance eccentricity on the unbalanced ball’s motion was investigated.

A Statistical Study of Process Variables to Optimize a High Speed Curtain Coater: Part I

TAPPI Journal ◽  
2009 ◽  
Vol 8 (1) ◽  
pp. 20-26 ◽  
Author(s):  
PEEYUSH TRIPATHI ◽  
MARGARET JOYCE ◽  
PAUL D. FLEMING ◽  
MASAHIRO SUGIHARA
Keyword(s):  
Boundary Layer ◽  
Experimental Design ◽  
High Speed ◽  
Statistical Study ◽  
Process Variables ◽  
High Speeds ◽  
The Stability ◽  
Air Removal ◽  
Removal System

Using an experimental design approach, researchers altered process parameters and material prop-erties to stabilize the curtain of a pilot curtain coater at high speeds. Part I of this paper identifies the four significant variables that influence curtain stability. The boundary layer air removal system was critical to the stability of the curtain and base sheet roughness was found to be very important. A shear thinning coating rheology and higher curtain heights improved the curtain stability at high speeds. The sizing of the base sheet affected coverage and cur-tain stability because of its effect on base sheet wettability. The role of surfactant was inconclusive. Part II of this paper will report on further optimization of curtain stability with these four variables using a D-optimal partial-facto-rial design.

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