Data to Be Included in Lateral Reports

							                                    ANNEX C
                Report Requirements for Lateral and Stability Analyses


1. Standard Lateral Analysis and Stability Report

       A. Rotor Model
              i.   Sketch of rotor model
              ii.  Clear identification of bearing, shaft end and internal seals, probe,
                   coupling, and disc (impellers, wheels, etc) locations
       B. Oil Film Bearings and Liquid-film Seals Data (if present)
              i.   Dynamic coefficients (plot or table) for minimum and maximum
                   stiffness cases vs. speed and power
              ii.  In the Level II Stability analysis, the synchronous and/or non-
                   synchronous coefficients when used by manufacturer
              iii. Identification of coordinate system including direction of rotation
              iv. Bearing type, length, pad arc length, diameter, minimum and
                   maximum clearance, offset, number of pads, load geometry, preload
                   and pivot type and geometry
              v.   Bearing load and direction vs. speed and power
              vi. Oil film seal configuration, length, diameter, minimum and
                   maximum clearance, load geometry, and seal geometry
              vii. Oil properties and operating conditions
                     a. Oil viscosity (two temperature data if a non-standard ISO
                         Grade)
                     b. Oil flow rate and/or inlet pressure
                     c. Inlet operating temperature range and permissive to start
                         temperature
                     d. Oil specific gravity
                     e. Seal operating conditions
       C. Rolling Element Bearing Data
              i.   Type and model number
              ii.  Dynamic coefficients vs. frequency and speed
              iii. Bearing loads and preload
       D. Bearing Pedestal Data
              i.   Identify parameters vs. frequency (mass, stiffness and damping)
       E. Gas Seal Data
              i.   Coefficients (when a Level 2 analysis is required) for labyrinth
                   seals, balance piston seal, and/or center bushing seal
              ii.  Seal type (labyrinth, honeycomb, hole pattern, etc.)
              iii. Teeth on rotor, teeth on stator or interlocking
              iv. Seal minimum and maximum operating clearance
              v.   Presence of shunt holes and/or swirl brakes
       F. Squeeze Film Dampers
              i.   Dynamic coefficients (plot or table) for clearance extremes vs.
                   frequency
       ii.  State static position & whirl eccentricity assumptions or calculation
       iii. Identification of coordinate system including direction of whirl
       iv.  Damper type, length, diameter, minimum and maximum clearance,
            centering device and end seal type
      v.    Stiffness values for end seals and centering device (when used)
G. Other Forces Included in the Analysis (Machine Dependent)
      i.    Motor stator magnetic stiffness
      ii.   Volute fluid dynamic forces
      iii. Partial arc steam loads
      iv. Gear mesh loads
      Note: Vendor should state force magnitude and basis of calculation
H. Analysis Methods
      i.    List computer codes used in the analysis with a brief description of
            the type of code, e.g., finite element, CFD, transfer matrix, etc.
I. Undamped Critical Speed Map and Mode Shapes
      i.    Critical speed vs. support stiffness
      ii.   Curves of the support stiffness (i.e. Kxx and Kyy for minimum and
            maximum stiffness)
      iii. Plot, as a minimum, the first 4 critical speeds with the stiffness axis
            extending to “rigid and soft support” regions
      iv. Show the minimum allowable and maximum continuous speeds
      v.    The map shall be displayed as shown in Figure XX.1-1)
      vi. Undamped mode shapes from the rigid, expected and soft support
            regions
      vii. For machines that do not have similar support stiffness, the critical
            speed map shall indicate the specified reference bearing and its
            location. For each of the other bearing locations, the bearing
            stiffness ratio, relative to the specified reference bearing, shall be
            defined.
              a. The vendor can substitute mode shape plots for the undamped
                  critical speed map and list the undamped critical speeds and the
                  support stiffness for each of the identified modes.
               Figure XX.1-1) Undamped Critical Speed Map

J. Unbalance Response Predictions
      i.   Identification of the frequency of each critical speed in the range
           from 0 to 1.5 x Nmc
      ii.  Frequency, phase and amplitude (Bode plots) at the vibration probe
           locations in the range 0 to 1.5 x Nmc resulting from the unbalances
           specified in SP6.8.2.7 & SP6.8.2.8.
             a. If there are no vibration probes near a bearing centerline then
                 the Bode plots shall be shown at the bearing centerline.
             b. Minimum allowable and maximum continuous speed shown
      iii. Tabulation of critical speeds, amplification factor, actual and
           required separation margin and scale factor
      iv. Axial location, amount and phase of unbalance weights for each
           case
      v.   Plots of amplitude and phase angle vs. speed at probe locations
             a. For min and max bearing stiffness cases
               b. Pedestal vibration amplitudes for flexible pedestals as defined
                   in SP6.8.2.4.e.
       vi.    Plots of deflected rotor shape at critical speeds and Nmc – For min
              and max bearing stiffness cases
       vii.    A table of the close clearance magnitudes and locations and
              maximum vibration levels verifying that SP6.8.2.11.1 has been met.

K. Stability Level 1 Analysis
      i.     The calculated anticipated cross coupling, qa, (for each centrifugal
             impeller or axial stage), total anticipated cross coupling, Qa, log dec
             and damped natural frequency at anticipated cross coupling, and
             Q0/Qa
      ii.    Figure XX.1-2 plot of log dec vs. cross coupled stiffness for min &
             max bearing stiffness




              Figure XX.1-2) Level I Stability Sensitivity Plot

       iii.   Figure XX.1-3 plot of flexibility ratio vs. average gas density with
              application point(s) identified on plot.
                        Figure XX.1-3) Stability Experience Plot

       L. Stability Level II Analysis
             i.     Description of all assumptions used in the analysis
             ii.    Description of all dynamic effects included in the analysis
             iii. Value of log dec and frequency versus component addition for min
                    & max bearing stiffness (Defined in SP6.8.6.2-7)
       M. Summary Sheet that identifies compliance with API requirements


2. Data Required to Perform Independent Audits of Lateral Analysis and Stability
   Reports (SP6.8.1.4.2)

       A. All of the requirements of XX.I.1 shall be met. This requirement details
          additional data that must be provided in conjunction with the Standard Report
          or as an addendum to it.
       B. Rotor model
              i.    Model tabulation to include rotor geometry (including delineation
                    between stiffness and mass diameter) and external masses with
                    weight, polar, and transverse moments of inertia
              ii.   The weight, polar and transverse moments of inertia and center of
                    gravity of the impellers, balance piston, shaft end seals, coupling(s)
                    and any other rotating components
              iii. Shaft Material Properties (density and Young’s Modulus with
                    temperature dependence)
              iv. Axial pre-loading due to tie bolts
              v.    The magnitude and direction of any additional side loads (gears
                    forces, partial arc admission, etc.) over the full operating range
C. Bearing and liquid-film seal
       i.    Data to permit independent calculation of bearing coefficients
               a. Table XX.I-1 and Figures XX.I-1&2 indicate geometry
                   required for tilt pad bearings.
                   Note: Similar dimensions are required for fixed pad bearings
                   when used. API 684 can assist in the determination of the
                   dimensions needed.
       ii.   Tilt pad bearing and pivot material
       iii. Seal dimensional data
D. Internal seals (labyrinth, balance piston seal, wear rings and center bushing
   seal)
       i.    Data to permit independent calculation of seal coefficients
               a. Dimensional data
               b. Inlet swirl ratio
               c. Swirl brake type
               d. Clearance assumptions
               e. Shunt hole location
               f. Gas conditions and properties at operating speed
          Dimension                 Nominal        Tolerance
                                                 (+)        (-)

   Journal Diameter (2*Rj)
Pad Machined Diameter (2*Rp)
       Set Bore (2*Rb)
      Pivot Location ()
     Pad Arc Length ()
   Table XX.I-1) Tilt Pad Bearing Dimensions and Tolerances




    Figure XX.I-1) Geometry Definitions for Tilt Pad Bearing
Figure XX.I-2) Preloaded Pad