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Fluid Film Bearings

The ARMD software package is capable of facilitating comprehensive evaluations of fluid-film bearings. Practically any bearing or bearing system available in the industry can be analyzed with one of the bearing solution modules. The FLUID-FILM bearing modules (JURNBR, HYBCBR, TILTBR, and THRSBR) solve the lubrication problem in two dimensions eliminating any approximation typically associated with one dimensional analysis or with look-up table methods.

[Bearing Analysis]
[Bearing Analysis System] The release of RBTS’ ARMD Version 6 fluid-film bearing modules is a major milestone in the product’s development history, rolling out a completely new and improved graphical user interface for the package with enhanced numerical capabilities and new technical features. The software’s front end was redesigned with our customers’ and industry’s input to incorporate the most logical, efficient, and productive techniques to model and analyze common as well as complex configuration, fluid-film lubricated journal and thrust bearings, of all sizes with ease. ARMD JURNBR users will immediately see the improvements as bearing design data are presented in a flatter, more accessible format, with key fields and analysis options readily visible from the main data entry screens. Fluid-film bearing design and performance evaluation productivity is vastly improved as a wide selection of templates accompanied by a “wizard” style sequence of dialogs allows the user to setup and evaluate most of the commonly used bearings in industry with few key strokes. Tab selected grids and input forms allow the user to see all of the data on screen at the same time. Furthermore, the ability to simultaneously run multiple instances of the program permits rapid side-by-side comparison of results.

Complete performance predictions of hydrodynamic, hydrostatic, and hybrid lubricated journal, conical and thrust bearings operating in the laminar and/or turbulent regime can be generated. Simulation capabilities include effects as cavitation, misalignment, pressurized boundaries, pressurized grooved feeding system, pressurized nozzle feeding system, surface/structural deviation, and lubricant feed circuitry (JURNBR, HYBCBR) with specified pressures or restrictors (capillary, orifice, or flow control valve), groove geometry and chamfers

Results generated with the fluid-film bearing modules include:

● Load capacity /
   journal or runner
   position

● Attitude angle

● Viscous power loss

● Righting moments

● Flow requirements

● Stability
   (bearing whirl)

● Spring and damping
   coefficients

● Clearance and
   pressure distribution

● Recess pressures
   and flows

● Heat balance and
   temperature rises for
   bearing system and
   individual pads

Bearing configurations and special features that can be evaluated with the solution modules include but are not limited to:

Fixed Geometry Cylindrical
and Conical Journal Bearings
(JURNR & HYBCBR)

○ Plain surface
○ Multi-groove
○ Pressure dam
○ Elliptical or lemon
○ Rayleigh step or pocket
○ Tapered land
○ Lobe or canted lobe
○ Any configurable pad surfaces
○ Multi-recess
Click here for brochure.

Tilting-Pad Journal Bearings (TILTBR)

○ Central pivot
○ Offset pivot
○ Evenly spaced pads
○ Grouped pads
○ Load between pads
○ Load on pad
○ Any load direction
○ Any preload
○ Leading/trailing edges taper
○ Fluid-inertia force effects
○ Support pivot stiffness
Click here for brochure.

Fixed and Tilting-Pad
Geometry Thrust Bearings
(THRSBR)

○ Plain surface
○ Multi-groove
○ Step land
○ Step pocket
○ Tapered land
○ Taper pocket
○ Tilting pad
○ Compound taper
○ Any configurable pad surfaces
Click here for brochure.

Illustrated below, complete bearing performance results are generated when the Run button is pressed. The solution is performed for user specified operating conditions taking into consideration the pressurized feeding system. Heat balance is performed for the overall bearing system as well as individual pads in the bearing.







Sample Presentations – 3D Fluid-Film Bearing Pressure & Clearance Distributions


Sample Presentations – 3D Fluid-Film Bearing Pressure & Clearance Distributions
RBTS has developed a 3-dimensional graphics utility to view bearing performance results. For illustration, below are selected graphic screens of various types of geometries analyzed with the fluid-film bearing modules implemented in the ARMD software package (click bearing to view details).
  1. Radial Bearing – Three (3) pad, fixed geometry cylindrical journal bearing, with tapered pocket configuration for high speed multi-stage centrifugal compressor operating at 8500 rpm.
  2. Radial Bearing – Four (4) pad, fixed geometry cylindrical journal bearing, with canted lobe configuration operating at 6,000 rpm for a compressor system in a steel plant.
  3. Radial Bearing – Pressure-dam, fixed geometry cylindrical journal bearing, for high speed turbine application operating at 9300 rpm.
  4. Radial Bearing – 4 millimeter diameter herringbone journal bearing for a spindle application operating at 10,000 rpm.
  5. Radial Bearing – Hydrostatic/Hybrid fixed geometry cylindrical journal bearing with surface deviations (structural deformation) for mining application.
  6. Radial Bearing – 3-Lobe, fixed geometry cylindrical journal bearing, with 50% axially tapered bore for marine application.
  7. Radial Bearing – Tilting Pad journal bearing for high speed turbo-expander application operating above 24K rpm.
  8. Thrust Bearing – Gearbox thrust bearing with 14 pad shrouded tapered land configuration operating at 15K rpm.







1- Three (3) pad, fixed geometry cylindrical journal bearing, with tapered pocket configuration for high speed multi-stage centrifugal compressor operating at 8500 rpm.
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2- Four (4) pad, fixed geometry cylindrical journal bearing, with canted lobe configuration operating at 6,000 rpm for a compressor system in a steel plant.
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3- Pressure-dam, fixed geometry
cylindrical journal bearing for high speed turbine application operating at 9300 rpm.
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4- 4 millimeter diameter herringbone journal bearing for a spindle application
operating at 10,000 rpm.
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5- Hydrostatic/Hybrid bearing for mining application.
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6- 3-Lobe, fixed geometry cylindrical journal bearing, with 50% axially tapered bore for marine application.
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7- Tilting Pad journal bearing for high speed turbo-expander application operating above 24K rpm.
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8- Gearbox thrust bearing with 14 pad shrouded tapered land configuration operating at 15K rpm.
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