Transcript Slide 1

2013 NEW Proposal to TRC
A test rig for evaluation of
thrust foil bearings and/or
face seals
Luis San Andrés
Mast-Childs Professor
May 2013
1
USET Thrust Bearing Test Rig
USET research
program (2005-08)
$ 787.3 k
Test rig: $288.5 k
Test Thrust
Bearing
0
6
12
Radial
Bearings
inch
Rotor
0
2
4 in
2
Objective & Tasks (2005-2008)
Test rig funded by USET (AF) program
• Design & construction of thrust bearing test rig.
• Measurements of axial clearance, load, pocket
pressures, and flow rates in a water hybrid
thrust bearing.
• Prediction of performance from tool XLHYDROTHRUST
and comparisons to test data.
3
Thrust Bearing Test Rig – Cross Section
Airbuffer Seals
Radial Hydrostatic
Bearings
Aerostatic
Bearings
shaker
Thrust Load
mechanism
0
2 in
4 in
Test Thrust
Bearing
or FACE
SEAL
Rotor
Assembly
Slave Thrust
Bearing
4
Schematic test rig: thrust and radial bearings as
mechanical elements with stiffness and damping
Thrust Bearings (Test & Slave): Kz, Cz
TB load shaft + housing (3.4 lb)
Rotor (8.7 lb)
Radial (air) Bearings: Kxx, Kyy, Cxx, Cyy
Radial (water) Bearings: Kxx, Kxy, Kyx, Kyy,
Cxx, Cyy, Cxy, Cyx
Test element: thrust bearing or face seal
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TEST RESULTS & PREDICTIONS
Water supply pressure=250 psig (17.2 bar)
5.0
7.5 kRPM Test
4.5
Predicted
12.5 kRPM Test
Clearance (mil)
4.0
Predicted
3.5
7.5 krpm
17.5 kRPM Meaured
Predicted
3.0
17.5 krpm
2.5
2.0
1.5
1.0
100
250 psig
150
200
250
300
Load (lb)
XLHYDROTHRUST
predictions
350
400
450
Axial clearances are weak
functions of rotor speed –
hydrostatic effect mainly
Predictions agree well
with test data, best at
highest load (400 lbf)
TB clearance vs. axial load: 7.5, 12.5 & 17.5 krpm
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Work in 2012-13
Dr. Sangshin Park (Visiting Scholar)
Test rig modified to
operate with air lubricated
bearings.
Flexure pivot
hydrostatic/hydrodynamic
air bearings designed and
manufactured ($7.5 k)
7
Proposed work
2013-2014 Year I
Complete revamping test rig: install instrumentation
and
• TRC member provides face seal or thrust foil
bearing for testing OR acquire thrust bearing.
• Install bearing and measure drag torque and film
thickness vs. applied axial load at increasing shaft
speeds.
Max speed: 30 kprm
Seal or Bearing OD: 3 inch
• Compare measurements to predictions from TB or
SGFace seal codes.
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8
TRC Budget
2013-2014 Year I
Year III
Support for graduate student (20 h/week) x $ 2,050 x 12 months
$ 24,600
Fringe benefits (0.6%) and medical insurance ($185/month)
$
2,368
Tuition & fees three semesters ($362/credit hour)
$
8,686
Other (manufacture TB and contribute to purchase ADRE system)
$ 8,346
Total Cost:
$ 44,00
TRC members wish to verify/validate predictive tools for
hydrodynamic thrust bearings and face seals.
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Questions (?)
10
10
Components of Motor Drive System
SKF Precision/Gilman Technologies
Spindle Motor Drive (D45985)
22KW (30 HP) @ 30,000 RPM
Constant torque 0 – 30,000 RPM (62 lb-in
torque)
Digital closed-loop speed control with
LabView interface
Water chiller
All subsequent required hardware and
software
Coupling Corp. of America (CCA), Custom
Coupling
- FLEXXOR Twin-diaphragm or Quill shaft design
with Anderson Locking hub(s)
30,000 RPM Maximum speed rating
825 lb-in max. continuous torque
+/- 0.024-0.048 inch Axial Travel allowance (> 8X req’d.)
Low axial spring rate (0.01 - 0.02 lb/0.001 inches)
Weight: 2.1 – 3.5 lbs.
Inertia (Ip): 2.6 – 5.3 lb-in^2
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Test Rig Operation
STATIC LOAD TESTS
Thrust and radial bearings lubricated with water at 91F (~32 C)
• Open water lines and SET supply pressure into radial bearings (100 psig)
• Supply pressure to gas bearings supporting axial load arm (100 psig)
• SET supply pressure into thrust bearings: 50, 100, 150, 200, 250 psig
• SET thrust bearings at nominal clearance (3 mil)
• SET rotor speed (max 25 krpm): 7.5, 10.5, 17.5 krpm
• Shaker applies axial load – increasing & decreasing
• MEASURE rotor axial displacements (clearances) at test & slave bearings,
RECORD flow rates (in & out), pocket pressures, supply and discharge P&T’s
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Test Rig Instrumentation
Rotor lateral radial motions: 2 x 2 (X,Y) eddy current sensors:
Rotor collar axial and tilt motions at test & slave thrust bearings
2 x 3 (120 deg) (Z) eddy current sensors:
Thrust Force with strain gauge load cell & stinger connected to shaker.
Torque mechanism not active.
Turbine flow meters in supply lines to water radial bearings, and
test thrust bearing INLET and OUTLET at ID
Three (3) strain-gauge pressure sensors for measurement of (2) pocket and (1)
land pressures in test thrust bearing.
Thermocouples: inlet & outlet of test thrust bearing
Pressure gauges: supply and discharge of test thrust bearing
Tachometer: rotor speed
LABVIEW® DAQ system and control
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ORIGINAL Flexure Pivot Tilting Pad Hybrid Bearings
O-ring
Grove
Nominal
Bearing
Pads
Alignment
Pins
1.5”
1.5”
Pockets
one per pad
Material: 330
Bearing Bronze
Wire-EDM
manufacturing
Modeled using
XLHYDROJET
Radial clearance
Inner Diameter
Outer Diameter
Length
Number of pads
Arc length
Pivot offset (dim)
Preload (dim)
Flexure stiffness
Axial length
Arc length
Depth
Mean Diameter
Pocket/wetted
area ratio
3 mil
1.5 inch
3.0 inch
1.5 inch
4
72 °
60% arc length
0.20
1,770 lbf-in/rad
0.50 inch
24 °
20 mil
2.16 inch
0.11
Inlet coefficient from 0.20
pocket to land
Orifices
Diameter
one per pocket radial injection
0.067 inch (1.7mm)
50% of pocket length
Y
X
Load
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ORIGINAL Thrust Hybrid Bearings
Thrust bearings
Material 660 Bearing bronze
Inner diameter: 1.60 inch
Outer diameter: 3.00 inch
Axial clearance 0.5-5.5 mil (nominal 3 mil)
Test bearing
EIGHT (8) Pockets:
Mean Diameter: 2.16 inch
radial length:
0.32 inch
Arc length:
20 degrees
Depth:
0.020 inch
Pocket/wetted area ratio = 19%
Orifice size:
0.071 inch
Axial injection at r=1.08 inch
Slave bearing
FLUID WATER
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Thrust Bearing Test Rig – Cross Section
Test Thrust
Bearing
Hydraulic shaker
delivers axial load Hydrostatic
to TB housing
Air Bearings
Slave Thrust
Journal Bearing
Bearings
Coupling
stinger
Rotor
Max Supply pressure:
250 psi, Top speed=25 krpm
Thrust
Shaft
Test
Bearing
Cover
Journal
Bearing
Housing
Double Thrust Bearing (TB) configuration – face
to face
Slave
Bearing
Housing
0
5
10 inch
Two flexure pivot
hydrostatic/hydrodynamic bearings
support rotor
Air bearings support test TB housing (friction free
axial motion)
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Thrust Bearing Test Rig – Exploded View
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