Bearing Skidding Detection for High Speed and Aero Engine Applications

2021 ◽  
Author(s):  
Azzedine Dadouche ◽  
Rami Kerrouche
Keyword(s):  
High Speed ◽  
Power Losses ◽  
Severe Damage ◽  
Roller Bearings ◽  
Custom Made ◽  
Rolling Element ◽  
Aero Engine ◽  
Oil Flow ◽  
Rolling Elements ◽  
Surface Distress

Abstract Rolling-element bearings (REB) can develop severe damage due to skidding (slipping) between the rolling elements and bearing races. Skidding can be described as gross sliding between the bearing surfaces in relative motion and can result in significant surface distress such as smearing, especially at light loads and high rotational speeds. Under these conditions, skidding occurs between the rolling elements and the bearing races, leading to increased wear (higher friction coefficient), elevated bearing temperature, significant power losses and reduced service life of the bearing. The main objective of this study is to investigate the significance of various sensing technologies (induction, vibration, ultrasound, acoustic and optical) in detecting skidding in standard series roller bearings as well as custom-made roller bearings for aero engine applications. The bearings have a bore diameter of 60 mm and 90 mm, respectively. Jet and under race lubrication techniques have been used to supply oil to the bearings under test. The custom-made aero engine test bearing features special channels to allow under race lubrication of the rollers/races contacts as well as the cage land. The effect of radial load, rotational speed and oil flow on roller skidding have also been investigated and analyzed. Tests have been performed on a dedicated high speed experimental bearing facility and data was recorded using a commercially-available data acquisition system.

Bearing Skidding Detection for High Speed and Aero Engine Applications

2021 ◽  
Author(s):  
Azzedine Dadouche ◽  
Rami Kerrouche
Keyword(s):  
High Speed ◽  
Power Losses ◽  
Severe Damage ◽  
Roller Bearings ◽  
Custom Made ◽  
Rolling Element ◽  
Aero Engine ◽  
Oil Flow ◽  
Rolling Elements ◽  
Surface Distress

Abstract Rolling-element bearings (REB) can develop severe damage due to skidding (slipping) between the rolling elements and bearing races. Skidding can be described as gross sliding between the bearing surfaces in relative motion and can result in significant surface distress such as smearing, especially at light loads and high rotational speeds. Under these conditions, skidding occurs between the rolling elements and the bearing races, leading to increased wear (higher friction coefficient), elevated bearing temperature, significant power losses and reduced service life of the bearing. The main objective of this study is to investigate the significance of various sensing technologies (induction, vibration, ultrasound, acoustic and optical) in detecting skidding in standard series roller bearings as well as custom-made roller bearings for aero engine applications. The bearings have a bore diameter of 60 mm and 90 mm, respectively. Jet and under race lubrication techniques have been used to supply oil to the bearings under test. The custom-made aero engine test bearing features special channels to allow under race lubrication of the rollers/races contacts as well as the cage land. The effect of radial load, rotational speed and oil flow on roller skidding have also been investigated and analyzed. Tests have been performed on a dedicated high speed experimental bearing facility and data was recorded using a commercially-available data acquisition system.

The Impact of Oil and Sealing Air Flow, Chamber Pressure, Rotor Speed, and Axial Load on the Power Consumption in an Aeroengine Bearing Chamber

2005 ◽  
Vol 127 (1) ◽  
pp. 182-186 ◽  
Author(s):  
Michael Flouros
Keyword(s):  
Power Consumption ◽  
High Speed ◽  
Air Flow ◽  
Flow Chamber ◽  
Chamber Pressure ◽  
Power Losses ◽  
Rolling Element ◽  
Oil Flow ◽  
The Impact ◽  
Circle Diameter

Trends in aircraft engines have dictated high speed rolling element bearings up to 3 million DN or more with the consequence of having high amounts of heat rejection in the bearing chambers and high oil scavenge temperatures. A parametric study on the bearing power consumption has been performed with a 124 mm pitch circle diameter (PCD) ball bearing in a bearing chamber that has been adapted from the RB199 turbofan engine DN∼2×106. The operating parameters such as oil flow, oil temperature, sealing air flow, bearing chamber pressure, and shaft speed have been varied in order to assess the impact on the power consumption. This work is the first part of a survey aiming to reduce power losses in bearing chambers. In the first part, the parameters affecting the power losses are identified and evaluated.

A General Theory for Elastically Constrained Ball and Radial Roller Bearings Under Arbitrary Load and Speed Conditions

1960 ◽  
Vol 82 (2) ◽  
pp. 309-320 ◽  
Author(s):  
A. B. Jones
Keyword(s):  
General Solution ◽  
General Theory ◽  
High Speed ◽  
Ball Bearings ◽  
Precise Location ◽  
Roller Bearings ◽  
Load Paths ◽  
Elastic Yielding ◽  
Rolling Element ◽  
Rolling Elements

A completely general solution is obtained whereby the elastic compliances of a system of any number of ball and radial roller bearings under any system of loads can be determined. Elastic yielding of the shaft and supporting structure are considered as well as centrifugal and gyroscopic loading of the rolling elements under high-speed operation. The solution defines the loading and attitude of each rolling element in each bearing of the system as well as the displacement of each inner ring with respect to its outer ring. For ball bearings the precise location of the load paths in each raceway are found. Life estimates can be more accurately made since the fatigue effects can be evaluated over known paths in the raceways. The solution, which is accomplished numerically by iterative techniques, has been programmed for an IBM-704 digital computer.

Cage Slip in Roller Bearings

1973 ◽  
Vol 15 (5) ◽  
pp. 370-378 ◽  
Author(s):  
K. T. O'Brien ◽  
C. M. Taylor
Keyword(s):  
Fatigue Life ◽  
Heat Generation ◽  
High Speed ◽  
Rolling Element Bearings ◽  
Design Problems ◽  
Adverse Conditions ◽  
Roller Bearings ◽  
Rolling Element ◽  
Low Load ◽  
Rolling Elements

The occurrence of cage and roller slip in lubricated roller bearings has been observed under adverse conditions of high speed and low load. Whilst slip is not normally a problem in roller bearings, in certain applications, for example the bearings supporting gas-turbine shafts, it can pose difficult design problems. For such conditions, bearing distress may occur due to increased wear and heat generation. A reduction of slip may be effected by the use of out-of-round races causing a preloading of some of the rolling elements; this, however, entails a corresponding reduction in fatigue life. Work described in this paper supplements the small amount of existing experimental evidence available concerning slip in rolling-element bearings. As well as a consideration of the effects of load and speed on slip, particular attention is paid to the quantity of lubricant supplied and the degree of misalignment present and the influence of these parameters on slip. Experimental results show a considerable divergence from previous results obtained using a similar bearing.

Reduction of Power Losses in Bearing Chambers Using Porous Screens Surrounding a Ball Bearing

2005 ◽  
Vol 128 (1) ◽  
pp. 178-182 ◽  
Author(s):  
Michael Flouros
Keyword(s):  
High Speed ◽  
Ball Bearing ◽  
Research Programme ◽  
Aircraft Engine ◽  
Chamber Pressure ◽  
Power Losses ◽  
Torque Measurements ◽  
Engine Design ◽  
Oil Flow ◽  
The Impact

Trends in aircraft engine design have caused an increase in mechanical stress requirements for rolling bearings. Consequently, a high amount of heat is rejected, which results in high oil scavenge temperatures. An RB199 turbofan bearing and its associated chamber were modified to carry out a survey aiming to reduce power losses in bearing chambers. The test bearing was a 124 mm PCD ball bearing with a split inner ring employing under-race lubrication by two individual jets. The survey was carried out in two parts. In the first part, the investigations were focused on the impact on the power losses in the bearing chamber of the operating parameters, such as oil flow, oil temperature, sealing air flow, bearing chamber pressure, and shaft speed. In the second part, the investigations focused on the reduction of the dwell time of the air and oil mixture in the bearing compartment and its impact on the power losses. In this part, porous screens were introduced around the bearing. These screens would aid the oil to flow out of the compartment and reduce droplet-droplet interactions as well as droplet-bearing chamber wall interactions. The performance of the screens was evaluated by torque measurements. A high-speed camera was used to visualize the flow in the chamber. Considerable reduction in power loss was achieved. This work is part of the European Research programme GROWTH ATOS (Advanced Transmission and Oil Systems).

Intermittent Chaotic Dynamics of Rail Axle Supported by Roller Bearings

2009 ◽  
Author(s):  
S. P. Harsha ◽  
C. ‘Nat’ Nataraj
Keyword(s):  
High Speed ◽  
Chaotic Dynamics ◽  
Chaotic Behavior ◽  
Period Doubling ◽  
Radial Clearance ◽  
High Speed Rail ◽  
Frequency Spectra ◽  
Roller Bearings ◽  
Nonlinear Springs ◽  
Rolling Elements

In this paper, intermittent chaotic analysis of high speed rail axle supported by roller bearings has been analyzed. In the analytical formulation, the contacts between rolling elements and races are considered as nonlinear springs, whose stiffness values are obtained by using Hertzian elastic contact deformation theory. The results show the appearance of instability and chaos in the dynamic response as the speed of the axle-bearing system is changed. Period doubling and mechanism of intermittency have been observed which lead to chaos. The appearance of regions of periodic, sub-harmonic and chaotic behavior is seen to be strongly dependent on the radial clearance. Poincare´ maps, time response and frequency spectra are used to elucidate and to illustrate the diversity of the system behavior.

scholarly journals Kinematic Correction for Roller Skewing

1982 ◽  
Vol 104 (1) ◽  
pp. 175-184
Author(s):  
M. Savage ◽  
S. H. Loewenthal
Keyword(s):  
High Speed ◽  
Roller Bearings ◽  
Transverse Curvature ◽  
Constant Radius ◽  
Rolling Elements ◽  
Convex Curvature ◽  
Cylindrical Roller

A theory of kinematic stabilization of rolling cylinders is developed for high-speed cylindrical roller bearings. This stabilization requires race and roller crowning to produce changes in the rolling geometry as the roller shifts axially. These changes put a reverse skew in the rolling elements by changing the rolling taper. Twelve basic possible bearing modifications are identified in this paper. Four have single transverse convex curvature in the rollers while eight have rollers with compound transverse curvature composed of a central cylindrical band of constant radius surrounded by symmetric bands with both slope and transverse curvature.

Oil Film Thickness Measurements on Surfaces Close to an Aero-Engine Ball Bearing Using Optical Techniques

2017 ◽  
Author(s):  
Jee Loong Hee ◽  
R. Santhosh ◽  
Kathy Simmons ◽  
Graham Johnson ◽  
David Hann ◽  
...  
Keyword(s):  
Film Thickness ◽  
Flow Rate ◽  
High Speed ◽  
Ball Bearing ◽  
Film Surface ◽  
Outer Periphery ◽  
Aero Engine ◽  
Oil Flow ◽  
Current Region ◽  
Counter Current

In a civil aero-engine transmission system a number of bearings are used for shaft location and load support. A bespoke experimental test facility in the University of Nottingham’s Gas Turbine and Transmissions Research Centre (G2TRC) was created to investigate oil shedding from a location bearing. An engine representative ball bearing was installed in the rig and under-race lubrication was supplied via under-race feed to three locations under the inner race and cage. The oil was supplied in an engine representative manner but the delivery system was modified to provide circumferentially even flow. An electromagnetic load system was designed and implemented to allow engine representative axial loads between 5 and 35 kN to be applied to the bearing. In this phase of testing the rig was operated at shaft speeds between 1,000 rpm and 7,000 rpm for a range of oil flow rates and low and high load conditions. The rig was designed with good visual access and high speed imaging was used to investigate film formation and movement on surfaces close to the bearing. This paper presents images and qualitative observations of thin film formed on the static surfaces forming the outer-periphery of the bearing compartment as well as the gap between orbiting cage and static outer race. Quantitative film thickness was obtained at two circumferential locations (90° and 270° from top dead centre) and three axial locations, through sophisticated analysis of the high speed images. The effect on film thickness of the varied parameters rotational speed, axial load and oil feed input flow rate are presented in this paper. It was observed that for all axial planes of measurement in both co-current and counter-current regions film thickness decreases with increase in shaft rotational speed. At 5,000 and 7,000 rpm film thicknesses are around 0.75 mm – 1 mm and are similar at 90° and 270°; at 3,000 rpm films tend to be somewhat thicker at around 1.5 mm – 2 mm and are thicker in the counter current region, particularly closer to the bearing. It is suggested that at higher shaft speeds interfacial shear dominates whereas at lower speed the effect of gravity in slowing the film in the counter-current region causes a measureable difference. It was further observed that increasing the input oil flow rate from 5.2 litres per minute to 7.3 litres per minute did not produce significant effect on film thickness. However, the increase of axial bearing load from 10 kN to 30 kN yielded thicker films at the location above the cage. In all cases there was waviness on the film surface at the bearing outer periphery; imaging was not sufficient to see if the film surface close to the bearing is wavy.

Analysis of a Rolling-Element Idler Gear Bearing Having a Deformable Outer-Race Structure

1963 ◽  
Vol 85 (2) ◽  
pp. 273-278 ◽  
Author(s):  
A. B. Jones ◽  
T. A. Harris
Keyword(s):  
Fatigue Life ◽  
High Speed ◽  
Roller Bearing ◽  
Rolling Element Bearing ◽  
Outer Ring ◽  
Outer Race ◽  
Rolling Element ◽  
Rolling Elements ◽  
Planet Gear ◽  
Bearing Rings

Conventional calculations of ball and roller bearing carrying capacity and fatigue life assume that the raceway bodies are rigid structures and that all elastic deformation occurs at the rolling elements’ contact with the raceways. In many instances, and particularly with aircraft applications, the bearing rings and their supports cannot be considered rigid. One such application is the planet gear in a transmission. This report develops a theory whereby the effects of the elastic distortions of the outer race of a rolling-element bearing on the internal load distribution and fatigue life of the bearing can be considered. The theory has been programmed for a high-speed, digital computer. An example of calculation for a planet gear roller bearing whose outer race is integral with the gear and of relatively thin section is given. The distortions of the flexible outer ring cause a significantly lower bearing fatigue life (L10) than would occur if the outer ring were rigid and considering a practical range of bearing diametral clearances. Mr. Jones developed the theoretical analysis for this paper and Mr. Harris provided the programming and the experimental data.

Fault Diagnosis of High Speed Rolling Element Bearings Due to Localized Defects Using Response Surface Method

2011 ◽  
Vol 133 (3) ◽  
Author(s):  
P. K. Kankar ◽  
Satish C. Sharma ◽  
S. P. Harsha
Keyword(s):  
Fault Diagnosis ◽  
Response Surface ◽  
Response Surface Method ◽  
High Speed ◽  
Mathematical Formulation ◽  
Rolling Element Bearings ◽  
Surface Method ◽  
Rolling Element ◽  
Rolling Elements ◽  
Localized Defects

In this paper, fault diagnosis of high speed rolling element bearings due to localized defects using response surface method has been done. The localized defects as spalls on outer race, on inner race, and on rolling elements are considered for this study. The mathematical formulation accounted for tangential motions of rolling elements and inner and outer races with the sources of nonlinearity such as Hertzian contact force and internal radial clearance. The nonlinear stiffness is obtained by the application of Hertzian elastic contact deformation theory. The mathematical formulation predicts discrete spectrum having peaks at the characteristic defect frequencies and their harmonics. Experimentation has also been performed to validate the results obtained from the mathematical model and it shows that the model can be successfully used to predict amplitude ratios among various spectral lines with localized surface defects. Combined parametric effects have been analyzed and their influence has been considered with design of experiments and surface response methodology is used to predict the dynamic response of a rotor bearing system.

Sign in / Sign up

Export Citation Format

Share Document