A test rig for evaluation of thrust foil bearings and/or face seals 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

USET Thrust Bearing Test Rig USET research program (2005-08) $ 787.3 k Test rig: $288.5 k Radial Bearings Test Thrust Bearing 6 12 inch Rotor 2 4 in

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.

Thrust Bearing Test Rig – Cross Section Airbuffer Seals Radial Hydrostatic Bearings Aerostatic Bearings shaker Thrust Load mechanism Rotor Assembly Test Thrust Bearing Slave Thrust Bearing 2 in 4 in or FACE SEAL

Schematic test rig: thrust and radial bearings as mechanical elements with stiffness and damping Test element: thrust bearing or face seal

TEST RESULTS & PREDICTIONS Water supply pressure=250 psig (17.2 bar) 7.5 krpm 17.5 krpm Axial clearances are weak functions of rotor speed – hydrostatic effect mainly Predictions agree well with test data, best at highest load (400 lbf) XLHYDROTHRUST predictions TB clearance vs. axial load: 7.5, 12.5 & 17.5 krpm

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)

Proposed work Complete revamping test rig: install instrumentation and 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. 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. 9 9

Questions (?) 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

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) 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 SET rotor speed (max 25 krpm): 7.5, 10.5, 17.5 krpm

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

ORIGINAL Flexure Pivot Tilting Pad Hybrid Bearings Material: 330 Bearing Bronze Wire-EDM manufacturing Modeled using XLHYDROJET

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) 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 Test bearing Slave bearing FLUID WATER

Thrust Bearing Test Rig – Cross Section Test Thrust Bearing Slave Thrust Bearing Hydraulic shaker delivers axial load to TB housing Journal Bearings Hydrostatic Air Bearings Coupling stinger Rotor Max Supply pressure: 250 psi, Top speed=25 krpm 5 10 inch Thrust Shaft Test Bearing Cover Journal Bearing Housing Slave Bearing Housing Two flexure pivot hydrostatic/hydrodynamic bearings support rotor Double Thrust Bearing (TB) configuration – face to face Air bearings support test TB housing (friction free axial motion)

Thrust Bearing Test Rig – Exploded View