Alfa-Tranzit Co., Ltd offers the new DYNAMICS R4.0 program system for analysis and design of rotor systems of high complexity

Transcription

1 ROTORDYNAMICS OF TURBOMACHINERY Alfa-Tranzit Co., Ltd offers the new DYNAMICS R4. program system for analysis and design of rotor systems of high complexity Copyright Alfa-Tranzit Co., Ltd

2 Unbalanced response 3D rotor model with unbalance Response curves in different sections of rotor model Unbalance response [t-pr] Amplitude and phase response curves 3D unbalance response plot Phase[ ] Unbalance response Subset [t-pr]

3 Synchronous and nonsynchronous response Twin-shaft rotor model n1= 2 rpm n2= rpm Unbalances of LP and HP rotors

4 25 (linear rotor models) (Time behavior plot due to impulse excitation Amplitude response versus rotor spin (acceleration and deceleration) External harmonic excitation (post processing results examples) Orbit ()

5 (nonlinear rotor systems) Response curves of linear rotor system with a retainer bearing Cascade plot (run-up and run-down) 25 2 Retainer bearing fixed No retainer bearing with a retainer bearing 2 Peak-to-peak curves

6 Point mass model with damper Point mass model Transient orbits for rotor model with weight (n = Const): a) unbalance =153 gsm) Orbit () Time response for rotor without weight (n=const ); ) unbalance =153 gsm) Orbit () - Orbit ()

7 Rotor model with damper supports Rotor model [1/min] [1/min] Peak-to peak ( EXEL) Mean value with dampers no dampers Y, mm [1/min] RPM

8 Point mass rotor with journal bearing Point mass rotor (n=const).15 Time response Harmonic analysis Orbit Orbit ()

9 Instability of point mass rotor with journal bearing Point mass rotor model Time response (n= rpm); 2D-orbits Orbit () Cascade plot [1/min] D-orbits RMS Mean value

10 Dynamic response of rotor with journal bearing Twin-mass case-rotor model (n=const) Time response of rotor Time response of case Rotor 3D-orbits Rotor 2D-orbits Orbit () Case orbits Orbit ()

11 Instability of rotor with journal bearing (1) Twin mass case-rotor model Rotor (YOZ) Rotor (XOZ) [1/min] [1/min] Case (YOZ) Case (XOZ)

12 Instability of rotor with journal bearing (2) Twin-mass case-rotor model Rotor orbits Orbit () Case orbits Orbit () n cr ~32 34 rpm Cascade plot Response analysis: 1. Rotor instability threshold n ~ 68 rpm (~ 2*n cr ) 2-d 3-d harmonics [e-2]

13 Elastic Damping Lateral Restraint (Clearance) Clearance element Modeling effects: rubs between rotor and stators; rubs between rotors; full and partial rubbings; external and internal damping; dry friction in contact point; slip response; weight; circumferential irregularity of clearance; etc

14 Elastic Damping Lateral Restraint (Clearance) Reverse (backward or dry) whirl due to rotor/stator interaction (impulse force on 7-th second) 2D-orbits Orbit () Cascade plot D orbits of rotor

15 Rotor instability due to internal damping Thresholds of instability Analytical solution (Jeffcott rotor, E.J. Gunter) Points for simulation ω = ω 2 R (1 + ) D 1 1+ R C D = C r b R = k k r b Stable motion (point 1) Unstable motion (point 2)