Transcript No Slide Title

33rd Turbomachinery Research Consortium Meeting
Estimation of Dynamic Force
Coefficients from a Wet (Foamy)
Annular Seal
$ 44,984
Gary Bradley
M.S. Student
Luis San Andrés
Mast-Childs Professor
TRC Project 32513/1519NS
Progress Year 1
May 2013
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Justification
Bubbly mixture annular seals
Seals operate with either liquids or gases, but not both…..
As oil fields deplete compressors work off-design with liquid in
gas mixtures, mostly inhomogeneous.
Similarly, oil compression station pumps operate with gas in
liquid mixtures.
The flow condition affects compressor or pump overall efficiency
and reliability.
Little is known about seals operating under 2-phase conditions,
except that the mixture affects seal leakage and system
reliability.
San Andrés, L., 2012, “Rotordynamic Force Coefficients of Bubbly Mixture Annular Pressure Seals, ”ASME J.
Eng. Gas Turbines Power, vol. 134 (Feb), 022503
Proposed Work (Year 1)
$ 44,984
• Prepare test rig for measurements (50%)
• Seal test rig (100%)
• Center journal/bearing, calibrate instrumentation, install
shakers (100%)
• Prepare motor to run up to 6000 rpm (50%)
• Prepare oil supply/return system (50%)
• Make air/oil mixing fixture that will produce consistent wet
(foamy) mixtures (50%)
• Fabricate mixing device
• Prepare mixing device for supply pressure up to 100 psig
• Construct de-aeration device
• Perform initial dynamic load measurements and devise a
procedure to extract the characteristic force coefficients (0%)
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Revamped vertical SFD rig
Air Inlet
Oil Inlet
(ISO VG 10)
Valves
Valves
Sparger
(mixing)
element
Test seal section
4
Test Rig Preparation
Seal section is currently
assembled and air tight
with no leaks
Oil supply/return pumps
all currently in working
order
Air supply in working
order (awaiting air flow
meter calibration)
Mixing (sparger) element
currently producing
mixtures (homogeneity of
mixture to be checked)
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Test Seal Section
Difficulties
• Too many sealing surfaces
• Sensor placement not ideal
• Plexiglas threads easily stripped
and cracked
Seal dimensions
Clearance, c=5 mil
Length, L=1.0 inch
Diameter, D=5.0 inch
Gasket
Top Plate 1
Top Plate 2
O-ring
Plexiglas
bearing
O-ring
Bottom Plate
Journal
(inside)
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New Design Test Seal Cartridge
Seal dimensions
Clearance, c=5-15 mil
Length, L=0.5-1.75 inch
Diameter, D=5.0 inch
Advantages
• Fewer sealing surfaces
• Sensor placement as needed
• Made of steel (no cracking/stripping
of material)
Top Plate
O-ring
Bearing
(steel)
Journal
Rotor
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Progress through Year 1
August 2012 – January 2013
•Ph.D. student funded
• Worked to seal test rig – Did not finish
• Quit in January of 2013
January 2013 – April 2013
•Project went without progress (no student)
April 2013 – Present
•Undergraduate student worker w/ supervision of grad student
• Sealed test rig (air tight, no leaks)
• Centered test rig
• Designed simpler test seal section (for future manufacture)
• Working to separate air from foamy mixture
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Outlook for Year 2
June 2013 – August 2013
• Finish preparing test rig
• Estimation of mixture properties (air/oil %, density, viscosity, etc.)
• Find new graduate student to take over project
August 2013 – December 2013
• Prepare data acquisition system
• Make initial measurements
January 2014 – May 2014
• Identification of seal force coefficients for a number of operating
conditions
• Write comprehensive TRC report and proposal for future work
No more funding is sought for 2013-14.
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