ROTOR DYNAMICS OF TURBOMACHINERYRelated materials:
Articles
- Leontiev M.K., Degtiarev S.A., Dynamics of rotor systems under seismic excitation
The paper presents the general theory of dynamic systems analysis under kinematic excitation. On its basis the methodology of analysis of rotor systems of general type being under seismic excitation was developed. The results of unsteady dynamic analysis of one degree of freedom system and a rotor supported by non-linear journal bearings are presented. The methodology and the algorithms are implemented into the Dynamics R4 program system developed to analyze the dynamic behavior of complex rotor systems.
[pdf]ENG (431 Kb)
- Leontiev M.K. , Degtiarev S.A. Vibration analysis of electric generator rotor supported on journal bearings
The present paper shows the calculation results of the separate generator “BRUSH” being the part of the system “the power turbine, the transmission and the generator”, with the aim of its stability thresholds determination. Several variant investigations are carried out. The task of the first research is to determine its stability thresholds on plain journal bearings in order to check two methodologies of determination of the rotor generator stability boundaries. The task of the second research is to determine the stability thresholds of the rotor on the elliptical journal bearings. Modeling and linear analysis of the generator rotor system was carried out previously [1].
[pdf]ENG (1.2 Mb)
Solutions
- Seismic capability ( Gas turbine - generator set structure) - [pdf]Eng (1.4 Mb)
- Oil Whirl and Whip, 2009
Oil whirl is a common problem with journal bearings used on machines equipped with pressure lubrication systems operating at relatively high speeds.
If the shaft is moved off center due to load, eccentricity, or imbalance, then the clearance on one side of the bearing will be greater than that on the other side.
As the lubricant rotates at less than 50% of shaft speed, it must squeeze through the narrow area where the shaft is closest to the bearing. The average speed of the lubricant increases inside the gap and slows down when it leaves the gap. Such a speeding up and slowing down process creates turbulence on both sides of the gap, and a vortex develops in the high-pressure lubricant zone.
[pdf]Eng (1.9 Mb)
- Rotordynamic Analysis of 120MW Turbine Generator, 2007
It is a calculation example of the power generator on 5 elliptical bearings. Rotation speed is 3600 rpm. Initial model of the generator was built on beams, inertial elements and journal bearings which are modeled by flexible links. Using Xlpocket and XLTltpad nonsymmetrical stiffness and damping matrixes for all journal bearings (USA, Rotating Machinery Technology, Inc.) were calculated. Frequencies, mode shapes at 3600 rpm and stability maps was obtained. Critical speeds were calculated.
[pdf]ENG (1.4 Mb)
- Multiplier of compressor stand - Modelling and analysis, 2007
The goal of this work are mathematic modeling of multiplier dynamic response which is used in the compressor stand assembly for AL55 engine. Research work was performed in the linear and nonlinear statement. Calculations in linear and nonlinear statement were carried out to determine natural frequencies and mode shapes of combined bending-torsional vibrations. Calculations at nonlinear transient statement allow to determine stability thresholds of the multiplier.
[pdf]Eng (2.5 Mb)
- GT2500-BRUSH generator drive train Modeling and Analysis, 2010
The task of the work is the determination of main resonant modes of the rotor drive train system ”GT25000 Power turbine – BRUSH generator” regarding all oscillation modes - bending, torsion and longitudinal ones. The following was done to accomplish this task: - the rotor system model creation;
- geometric and mass identification of the rotor system;
- calculation of natural frequencies and mode shapes of all types;
- calculation of critical speeds and the corresponding mode shapes;
- calculation of forced oscillation under the influence of the distributed system of unbalances.
Modeling was carried out in the Dynamics R4.5 program system by the company Alfa-Tranzit Co., Ltd on the basis of the data provided by Magellan Aerospace
[pdf]Eng (3.7 Mb)
