scholarly journals Improvement of Tilting-Pad Journal Bearing Operating Characteristics by Application of Eddy Grooves

Lubricants ◽  
2021 ◽  
Vol 9 (2) ◽  
pp. 18
Author(s):  
Eckhard Schüler ◽  
Olaf Berner
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Load Capacity ◽  
Fluid Film ◽  
Operating Characteristics ◽  
Fluid Film Bearings ◽  
Tilting Pad ◽  
Bearing Load ◽  
Bearing Loads ◽  
Tilting Pad Journal Bearing

In high speed, high load fluid-film bearings, the laminar-turbulent flow transition can lead to a considerable reduction of the maximum bearing temperatures, due to a homogenization of the fluid-film temperature in radial direction. Since this phenomenon only occurs significantly in large bearings or at very high sliding speeds, means to achieve the effect at lower speeds have been investigated in the past. This paper shows an experimental investigation of this effect and how it can be used for smaller bearings by optimized eddy grooves, machined into the bearing surface. The investigations were carried out on a Miba journal bearing test rig with Ø120 mm shaft diameter at speeds between 50 m/s–110 m/s and at specific bearing loads up to 4.0 MPa. To investigate the potential of this technology, additional temperature probes were installed at the crucial position directly in the sliding surface of an up-to-date tilting pad journal bearing. The results show that the achieved surface temperature reduction with the optimized eddy grooves is significant and represents a considerable enhancement of bearing load capacity. This increase in performance opens new options for the design of bearings and related turbomachinery applications.

Numerical Investigation for Characteristics and Oil-Air Distributions of a Tilting-Pad Journal Bearing Under Different Loads

2020 ◽  
Author(s):  
Aoshuang Ding ◽  
Xuesong Li
Keyword(s):  
Film Thickness ◽  
Journal Bearing ◽  
Viscosity Ratio ◽  
Cavitation Model ◽  
Tilting Pad ◽  
Sst Model ◽  
Bearing Load ◽  
Simulation Results ◽  
Bearing Loads ◽  
Tilting Pad Journal Bearing

Abstract This paper analyses the flow characteristics and oil-air distributions of oil flows in a tilting-pad journal bearing under different bearing loads. This titling-pad journal bearing is working at 3000 rpm rotation speed and its minimum film thicknesses have been measured under different loads from 180 kN to 299 kN. Based on the previous researches of this bearing under 180 kN, the gaseous cavitation and low-turbulence flow exists in this bearing flow. A suitable gaseous cavitation model and the SST model with low-Re correction are used in the film flow simulations. With the rotor and pads assumed to be rigid, the dynamic mesh and motion equations are applied to simulate the motions of the rotor and the rotations of the pads. Based on the simulation results under different bearing loads, the simulated minimum film thicknesses agrees well with the measured data. It indicates that the simulation results can catch the film geometries and flows correctly. With the load increasing, the rotor moves closer to the loaded pads and the minimum film thickness decreases. Taking the effect of boundary layers into consideration, the turbulence has a negative relationship with the film thickness and decreases in the loaded area under higher bearing load. It can be verified by the simulated lower turbulent viscosity ratio distributions in the loaded pads. In the unloaded area, both the film thickness and turbulence viscosity ratio are positively related to the bearing loads. Thus, the higher bearing load may lead the flow to be more different in the loaded and unloaded area, and the turbulence in the loaded pads may transfer to laminar in the end. As for the oil-air distributions, in the unloaded pads, with the bearing load increasing, the simulated air volume fraction increases in the unloaded pads with lower pressure. It should be caused by the higher film thickness of the unloaded pads under higher loads. In sum, the flow turbulence and cavitation process changes with the bearing load. With a higher load, the cavitation becomes more in the unloaded pads and the flow changes sharper from the high-turbulence unloaded area to the low-turbulence loaded area. As the simulation results is in good accordance with the experimental data, the SST model with low-Re correction and the gaseous cavitation model are verified to be suitable for bearing film simulations under different loads.

scholarly journals Testing, Analysis, and CFD Modeling of a Profiled Leading Edge Groove Tilting Pad Journal Bearing

1998 ◽  
Author(s):  
Stephen L. Edney ◽  
Gregory B. Heitland ◽  
Scan M. DeCamillo
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Leading Edge ◽  
Cfd Modeling ◽  
Operating Characteristics ◽  
Light Load ◽  
Operating Stability ◽  
Tilting Pad ◽  
Original Insight ◽  
Tilting Pad Journal Bearing

Testing and analysis of a profiled leading edge groove tilting pad journal bearing developed for light load operation is described. This bearing was designed for a generic, small, high speed steam turbine operating at projected loads of less than 25 psi (172.4 kPa) and journal surface speeds to 400 ft/s (122 m/s). On the second turbine application, a rotor instability was experienced with the oil flowrate reduced to optimize bearing steady state performance. This instability was eliminated by machining a taper on the exit side of the feed groove on each pad. At the reduced flowrate, the profiled groove bearing greatly improved the operating characteristics of the rotor system by reducing vibration amplitudes and stabilizing operation at speed. This paper is divided into two sections. The first section compares the rotordynamics analysis with test data that shows improved unbalance response and operating stability with the profiled groove bearing. The second section provides original insight of the effect of the profiled geometry on the bearing flow field using computational fluid dynamics models.

scholarly journals Measured and Predicted Operating Characteristics of a Tilting-Pad Journal Bearing with Jacking-Oil Device at Hydrostatic, Hybrid, and Hydrodynamic Operation

Lubricants ◽  
2018 ◽  
Vol 6 (3) ◽  
pp. 81 ◽  
Author(s):  
Thomas Hagemann ◽  
Peter Pfeiffer ◽  
Hubert Schwarze
Keyword(s):  
Journal Bearing ◽  
Operating Characteristics ◽  
Characteristic Parameters ◽  
Tilting Pad ◽  
Load Carrying ◽  
Manufacturing Tolerances ◽  
Stationary Conditions ◽  
Lift Off ◽  
Run Up ◽  
Tilting Pad Journal Bearing

Jacking-oil pockets are applied in many journals and thrust bearing applications in order to provide a hydrostatic oil film force that ensures a wear free run-up following a successful lift-off procedure. However, all components of the jacking-oil system have to be carefully designed in order to limit costs and prevent significant disturbance of hydrodynamic operation after deactivation of lift-oil. Experimental data and predictions for a four-pad tilting-pad journal bearing in load between pivot configuration are presented. Dynamic processes of the lift-off procedure as well as characteristic parameters of stationary conditions are studied. Moreover, hydrodynamic operation and hybrid lubrication providing a combined hydrodynamic and hydrostatic pressure distribution are investigated for sliding speeds up to 20 m/s. Analyzes of lift-off procedure prove that characteristic parameters such as lift-off pressures and vertical lift displacements are considerably influenced by manufacturing tolerances and misalignments. The comparison of hydrodynamic and hybrid lubrication provides a significant increase of load carrying capacity by additional jacking-oil supply at the maximum journal speed. In summary, results of measurements and predictions correlate well for all three investigated lubrication conditions.

Design, Analysis and Testing of an Inside-Out Tilting-Pad Journal Bearing With Real-Time Controllable Preload and Stiffness

2005 ◽  
Author(s):  
Maurice L. Adams ◽  
Michael A. Laurich
Keyword(s):  
Real Time ◽  
High Speed ◽  
Journal Bearing ◽  
High Stiffness ◽  
Tilting Pad ◽  
High Speed Grinding ◽  
Bearing Stiffness ◽  
Centerless Grinding ◽  
Tilting Pad Journal Bearing ◽  
Inside Out

It has recently been shown that high-speed grinding can be applied to the finishing of ceramics with considerable improvements in throughput and quality. This will require new high-speed high-power centerless grinding spindles (7,000 RPM, 50 HP), with high-stiffness of three hundred and fifty million Newtons/meter (2 million lb/in). To meet these requirements a novel inside-out, three-pad, pivoting-pad oil-fed hydrodynamic journal bearing has been devised, built and tested. One of the three pad’s pivot point is supported by a hydraulically-actuated radial-motion loading piston. This provides real-time controllable preload to all three bearing pads, thereby controlling bearing stiffness, providing less-stiff spindle bearings for initial rough grinding and very high stiffness spindle bearings for precision finish grinding. Extensive bearing test data compare favorably with theoretically predicted bearing performance.

Thermohydrodynamic Performance of a Tilting Pad Journal Bearing With Spot Lubrication

1991 ◽  
Vol 113 (3) ◽  
pp. 615-619 ◽  
Author(s):  
M. Tanaka
Keyword(s):  
High Speed ◽  
Journal Bearing ◽  
Safety Margin ◽  
Operating Conditions ◽  
New Method ◽  
Shaft Speed ◽  
Tilting Pad ◽  
Conventional Methods ◽  
Tilting Pad Journal Bearing

A new method of lubricant feeding is presented for tilting pad journal bearing and its effect on the thermohydrodynamic performance of the bearing is investigated theoretically and experimentally for various operating conditions. The new method can significantly reduce the maximum pad temperature compared with conventional methods, and its effect becomes pronounced with the increase in operating shaft speed. The method is promising for high speed journal pad bearing which is rapidly decreasing a safety margin against seizure due to the dangerously rising maximum pad temperature.

Diesel Engine Turbocharger Stabilized With Novel Tilting Pad Bearing Design

2012 ◽  
Author(s):  
R. Gordon Kirk ◽  
Matthew Enniss ◽  
Daniel Freeman ◽  
Andrew Brethwaite
Keyword(s):  
High Speed ◽  
Fluid Film ◽  
Pressure Pulsations ◽  
The Past ◽  
Fluid Film Bearings ◽  
Film Instability ◽  
Tilting Pad ◽  
Full Speed ◽  
Bearing Design ◽  
Engine Testing

Many high speed turbochargers operate with limit cycle vibration as a result of fluid-film instability. This problem has been under investigation for the past seven years. Only now has a turbocharger with fluid film bearings been run to full speed and loaded, with essentially no bearing induced sub-synchronous vibration. The goal of this research was to have a stable synchronous response with a minimum of non-synchronous contribution excited only by the engine dynamics and exhaust pressure pulsations. Previous papers have documented experimental results of the fixed geometry bearing designs. This paper documents a new, modified tilting pad bearing concept that has replaced the fixed geometry bushings with minimal modifications to the stock bearing housing. The summary of the on-engine testing over the past year is documented in this paper.

Evaluation of Pivot Stiffness for Typical Tilting-Pad Journal Bearing Designs

1988 ◽  
Vol 110 (2) ◽  
pp. 165-171 ◽  
Author(s):  
R. G. Kirk ◽  
S. W. Reedy
Keyword(s):  
High Speed ◽  
Fluid Film ◽  
Hertzian Contact ◽  
Tilting Pad ◽  
Hertzian Contact Stress ◽  
Bearing Stiffness ◽  
Stress And Deformation ◽  
The Individual ◽  
Stiffness And Damping ◽  
Tilting Pad Journal Bearing

The manufacturers of high speed turbomachinery are concerned with the accurate prediction of rotor response and stability. One major factor in the placement of system critical speeds and amplification factors is the stiffness and damping of both the fluid-film bearing and support structure. Typical calculated results for tilting-pad fluid-film bearings have neglected the influence of the point or line contact of the pivot support for the individual pads. This paper will review the equations developed considering the Hertzian contact stress and deformation theory and present the equations for pivot stiffness necessary for inclusion in tilting pad bearing computer programs. In addition, the influence of various standard pivot designs will be compared for typical fluid-film bearing stiffness and damping characteristics.

Experimental Study of Tilting-Pad Journal Bearings—Comparison With Theoretical Thermoelastohydrodynamic Results

1992 ◽  
Vol 114 (3) ◽  
pp. 579-587 ◽  
Author(s):  
Michel Fillon ◽  
Jean-Claude Bligoud ◽  
Jean Freˆne
Keyword(s):  
Experimental Study ◽  
Theoretical Model ◽  
Rotational Speed ◽  
Journal Bearing ◽  
Journal Bearings ◽  
Operating Conditions ◽  
Operating Characteristics ◽  
Tilting Pad ◽  
Tilting Pad Journal Bearing ◽  
Tilting Pad Journal Bearings

Operating characteristics of four-shoe tilting-pad journal bearings of 100 mm diameter and 70 mm length are determined on an experimental device. The load, between pad configuration, varies from 0 to 10,000 N and the rotational speed is up to 4000 rpm. Forty thermocouples are used in order to measure bearing element temperatures (babbitt, shaft, housing and oil baths). The influence of operating conditions and preload ratio on bearing performances are studied. Comparison between theoretical and experimental results is presented. The theoretical model is also performed on a large tilting-pad journal bearing which was investigated experimentally by other authors.

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