TRC-SFD-1-06 - Tribology Group - Texas A&M University

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VI Identification of Squeeze Film Damping and InertiaCoefficients for Lubricated SFDVI.1 Experimental procedureWith lubricant flowing through the damper lands, single frequency dynamic loadsare applied into the test system to produce centered circular orbits (CCO). The testsinclude four increasing motion amplitudes (12 μm to 50 μm) at frequencies rangingfrom 20 Hz to 70 Hz. and for two sets of flow restrictors (2.8 mm and 1.1mmdiameter holes). The largest motion amplitude amounts to ~ 40% of the damper radialclearance. Table 1 presents the test conditions.Table 2 Test conditions for dynamic load tests (CCO). Lubricated SFDInlet Pressure (P s ) *31 kPaRecirculation Annulus Pressure (P r )* 8.6 kPa-15.5 kPaFrequency Range20-70 Hz (2 Hz step)Lubricant temperature (T) 23-25 0 C (73-77 0 F)Viscosity (η)3.1 cP- 2.8 cPClearance (c)125-127 μm (4.9-5 mils)Orbit amplitude (e)12-50 μm (0.5-2 mils)Flow restrictors (hole diameter) 2.8 mm and 1.1mm*: Gauge pressure.Throughout the test frequency range, the applied dynamic load is set to maintainconstant amplitude circular orbits (12 μm, 25 μm, 38 μm, 50 μm). Figures 15 through 18show the applied loads (Y vs. X) and ensuing displacement orbits at 20 Hz and 70 Hz forthe two flow restrictor configurations tested. Appendix C includes excitation force anddisplacements orbits at other selected frequencies ranging from 20 Hz to 70 Hz.28
300150Y Load [N]-300 -150 0 150300-150-300X Load [N]20 Hz130Y Displacement [μm]12 μm25 μm38 μm65-130 -65 0 6550 μm-65Max. clearance:127 μm20 Hz130-130X Displacement [μm]Figure 15 Recorded load and ensuing displacement orbits for four amplitude load levels.Clearance circle noted . (20 Hz, lubricated SFD, CCO, 2.8 mm diameter flow restrictor)29
Page 4: List of TablesTable 1 Structural st
Page 8 and 9: Nomenclaturec Bearing radial cleara
Page 10 and 11: II Literature ReviewDella Pietra an
Page 12 and 13: III Test Rig DescriptionThe test ri
Page 14 and 15: Oil inletEddy current sensorHousing
Page 16: III.2 Lubrication systemFigure 5 de
Page 20 and 21: 0.02Work-Energy Dissipated [N.m]0.0
Page 22 and 23: V Measurements of flow rate in lubr
Page 26: 1.210.8Flow Rate0.60.40.2Flow restr
Page 31 and 32: 300150Y Load [N]-300 -150 0 150300-
Page 33 and 34: 300250XY200Load [N]150Amplitude of
Page 35 and 36: 21.75Film thickness(3x)0.250[mm]Abs
Page 37 and 38: VI.2 Parameter identification metho
Page 39 and 40: where M s-xx , C s-xx , M s-yy and
Page 41 and 42: Table 3 SFD inertia coefficients id
Page 43 and 44: 3512 μmCC xxs-xxDamping coefficien
Page 45 and 46: the dry friction interaction to the
Page 47 and 48: 353020 HzC SFDxx s-xxDamping coeffi
Page 49 and 50: opposed to the system damping coeff
Page 51 and 52: VII Conclusions and Recommendations
Page 53 and 54: VIII References[1] Zeidan, F.Y., Sa
Page 55 and 56: Appendix A Identification of Test S
Page 57 and 58: 6 . 105X/F [m/N]4 . 1052 . 105Exper
Page 59 and 60: Appendix B Uncertainty analysis of
Page 61 and 62: 2⎡⎛∂gal.⎞ ⎤Ucalib. = ⎢
Page 63 and 64: Flow (LPM)Flow (LPM)Flow (LPM)4.03.
Page 65 and 66: 30013015012 μm25 μm38 μm65Max. c
Page 67 and 68: 300130150-300 -150 0 15030012 μm25
Page 69 and 70: 300130150-300 -150 0 15030012 μm25
Page 71 and 72: Re(Hd) [MN/m]Re(Fxyx) [MN/m]202Im(H
Page 73 and 74: Re(Hd) [MN/m]Re(Fxyx) [MN/m]202Im(H

TRC-SFD-1-06 - Tribology Group - Texas A&M University

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