This paper investigates active real-time balancing of rigid rotors during the transient time of acceleration. First, the governing equation of motion of a rigid rotor is formulated. A parametric adaptive control scheme is then designed based on this dynamic model. An ordinary recursive least squares estimation method is used to estimate parameters in this adaptive control scheme. A supervisory ...

In this paper non-synchronous vibration (NSV) of a GE axial compressor is simulated using a fully coupled fluid/strcuture interaction (FSI). Time accurate NavierStokes equations are solved with a system of 5 decoupled structure modal equations in a fully coupled manner. A 3rd order WENO scheme for the inviscid flux and a 2nd order central differencing for the viscous terms are used to resolve n...

Flywheel energy storage has distinct advantages over conventional energy storage methods such as electrochemical batteries. Because the energy density of a flywheel rotor increases quadratically with its speed, the foremost goal in flywheel design is to achieve sustainable high speeds of the rotor. Many issues exist with the flywheel rotor operation at high and varying speeds. A prominent probl...

The nonlinear coupling vibration and bifurcation of a high-speed centrifugal compressor with a labyrinth seal and two air-film journal bearings are presented in this paper. The rotary shaft and disk are modeled as a rigid Jeffcott rotor. Muszynska’s model is used to express the seal force with multiple parameters. For air-film journal bearings, the model proposed by Zhang et al. is adopted to e...

This paper presents an investigation on the undesirable vibration of an oblique-stud stator frame in a large hydropower generator by means of experimental and finite element (FE) analysis. First, field experimental tests were performed, and the results indicate that the main vibration component comes from electromagnetic factors. Then, a 2D-magnetic and 3D-mechanical FE model was developed to i...

Synchronous generators are of two type’s salient pole type and round rotor type. The load angle curve of a cylindrical rotor synchronous machine comprises a single sine term only while in salient pole synchronous generators, power-angle characteristic has two terms. The first term is the fundamental component due to field excitation (the same as the cylindrical rotor) and the second term ...

This paper presents theoretical models and simulation results for the synchronous, thermal transient, instability phenomenon known as the Morton effect. A transient analysis of the rotor supported by tilting pad journal bearing is performed to obtain the transient asymmetric temperature distribution of the journal by solving the variable viscosity Reynolds equation, a 2D energy equation, the he...

Abstract: Rotating machinery is common in any industry. Rotating machinery in the modern era are designed for higher running speeds, tighter clearances and working under extreme conditions enhancing efficiency of the system to produce and transmit more power. All these lead to many rotordynamic challenges. Main cause of vibrations is faults in the rotating systems like unbalance, looseness, etc...

In this paper, bispectral analysis of vibration signals is used to assess health conditions of different rotatingcomponents in an AH-64D helicopter tail rotor drive train. First, cross-bispectral analysis is used to investigate drive-shaft faulted conditions -namely misalignment, imbalance, and a combination of misalignment and imbalance -with respect to a baseline case. The magnitude of the cr...

This study aims to determine change in optimal locations of dual trailing-edge flaps for various thrust coefficient to solidity (Ct /σ) ratios of helicopter to achieve minimum hub vibration levels, with low penalty in terms of required trailing-edge flap control power. Polynomial response functions are used to approximate hub vibration and flap power objective functions. Single objective and mu...