Active Rotor-Blade Vibration Control Using Shaft-Based Electromagnetic Actuation

2004 ◽  
Vol 128 (3) ◽  
pp. 644-652 ◽  
Author(s):  
René H. Christensen ◽  
Ilmar F. Santos
Keyword(s):  
Rotor Blade ◽  
Experimental Tests ◽  
Centralized Control ◽  
Blade Vibration ◽  
Electromagnetic Actuators ◽  
Blade System ◽  
Bladed Rotor ◽  
Displacement Transducers ◽  
System Configurations ◽  
Controllability And Observability

In this paper the feasibility of actively suppressing rotor and blade vibration via shaft-based actuation is studied. A mathematical model is derived, taking into account the special dynamical characteristics of coupled rotor-blade systems, such as centrifugal stiffened blades and parametric vibration modes. An investigation of controllability and observability shows that if the blades are properly mistuned, it is possible to suppress shaft as well as blade vibration levels by using only shaft-based actuation and sensing; though, in tuned bladed systems, shaft as well as blade actuation and sensing are required. In order to cope with the time-variant dynamics of the coupled rotor-blade system, a periodic time-variant modal controller is designed, implemented, and experimentally tested. A test rig built by four flexible blades is specially designed for this purpose. The rig is equipped with six electromagnetic actuators and different types of sensors (eddy-current displacement transducers, acceleration transducers, and strain gages) with the aim of monitoring and controlling shaft and blade vibration levels. Two different actively controlled rotor-blade system configurations are considered in the present study: (i) a tuned bladed rotor, controlled with help of actuators attached to the rotating blades and shaft-based actuators; (ii) a deliberately mistuned bladed rotor controlled only via shaft-based actuation. Experimental tests are carried out for both configurations. Some experimental problems regarding control implementation are identified and discussed, especially when the controller order and the number of actuators in the centralized control scheme become too high; though, for the mistuned bladed rotor controlled by using only shaft-based actuation, the controller works well.

scholarly journals Control of Rotor-Blade Coupled Vibrations Using Shaft-Based Actuation

2006 ◽  
Vol 13 (4-5) ◽  
pp. 255-271 ◽  
Author(s):  
René Hardam Christensen ◽  
Ilmar Ferreira Santos
Keyword(s):  
Active Control ◽  
Mode Shape ◽  
Rotor Blade ◽  
Experimental Control ◽  
Dynamical Characteristics ◽  
Blade Vibrations ◽  
Blade System ◽  
Bladed Rotor ◽  
Controllability And Observability ◽  
Interaction Phenomena

When implementing active control into bladed rotating machines aiming at reducing blade vibrations, it can be shown that blade as well as rotor vibrations can in fact be controlled by the use of only shaft-based actuation. Thus the blades have to be deliberately mistuned. This paper investigates the dynamical characteristics of a mistuned bladed rotor and shows how, why and when a bladed rotor becomes controllable and observable if properly mistuned. As part of such investigation modal controllability and observability of a tuned as well as a mistuned coupled rotor-blade system are analysed. The dependency of the controllability and observability on varying rotational speed and mode shape interaction phenomena between parametric and basis mode shape components are also analysed. Numerical results reveal a limitation of the achievable controllability and observability, once quantitative measures of modal controllability and observability converge toward steady levels as the degree of mistuning is increased. Finally, experimental control results are presented to prove the theoretical conclusions and to show the feasibility of controlling rotor and blade vibrations by means of shaft-based actuation in practice.

A Study of Active Rotor-Blade Vibration Control Using Electro-Magnetic Actuation: Part 2 — Experiments

2004 ◽  
Author(s):  
Rene´ H. Christensen ◽  
Ilmar F. Santos
Keyword(s):  
Vibration Control ◽  
Rotor Blade ◽  
Controller Design ◽  
Modal Control ◽  
Magnetic Actuation ◽  
Centralized Control ◽  
Blade Vibration ◽  
Control Scheme ◽  
Bladed Rotor ◽  
Electro Magnetic

This is the second paper in a two-part study on active rotor-blade vibration control using electro-magnetic actuation. This part is focused on experimental aspects of implementing active control into coupled rotor-blade systems. A test rig, equipped with electro-magnetic actuators and various sensors to monitor the system vibration levels, is specially designed. The aim of the rig is to demonstrate the feasibility of controlling rotor and blade vibrations using a modal control scheme capable to handle the time-periodicity of this kind of system. Two different active controlled rotor-blade systems are considered in the present study: (a) a tuned bladed rotor, controlled with help of actuators attached to the rotating blades; (b) a deliberately mistuned bladed rotor controlled only by shaft based actuation. Experimental tests are carried out for both systems. Some experimental problems regarding control implementation are identified and discussed especially when the controller order and the number of actuators in the centralized control scheme become too high. For the blade mistuned system, controlled by using only rotor/hub based actuation, the controller works well. Despite of implementation difficulties of the modal control scheme due to high sensitivity to model imperfections, it can be concluded that the periodic modal control methodology applied to controller design works well and can become a very useful and powerful tool for designing mechatronic machine elements.

Modeling of a Wind Turbine Rotor Blade System

2017 ◽  
Vol 139 (5) ◽  
Author(s):  
Dayuan Ju ◽  
Qiao Sun
Keyword(s):  
Wind Turbine ◽  
Rotor Blade ◽  
Simulation Software ◽  
Wind Flow ◽  
Coupling Effects ◽  
Horizontal Axis Wind Turbine ◽  
Blade Vibration ◽  
Proposed Model ◽  
Blade System ◽  
Coupling Terms

In wind turbine blade modeling, the coupling between rotor rotational motion and blade vibration has not been thoroughly investigated. The inclusion of the coupling terms in the wind turbine dynamics equations helps us understand the phenomenon of rotor oscillation due to blade vibration and possibly diagnose faults. In this study, a dynamics model of a rotor-blade system for a horizontal axis wind turbine (HAWT), which describes the coupling terms between the blade elastic movement and rotor gross rotation, is developed. The model is developed by using Lagrange's approach and the finite-element method has been adopted to discretize the blade. This model captures two-way interactions between aerodynamic wind flow and structural response. On the aerodynamic side, both steady and unsteady wind flow conditions are considered. On the structural side, blades are considered to deflect in both flap and edge directions while the rotor is treated as a rigid body. The proposed model is cross-validated against a model developed in the simulation software fatigue, aerodynamics, structure, and turbulence (fast). The coupling effects are excluded during the comparison since fast does not include these terms. Once verified, we added coupling terms to our model to investigate the effects of blade vibration on rotor movement, which has direct influence on the generator behavior. It is illustrated that the inclusion of coupling effects can increase the sensitivity of blade fault detection methods. The proposed model can be used to investigate the effects of different terms as well as analyze fluid–structure interaction.

A Study of Active Rotor-Blade Vibration Control Using Electro-Magnetic Actuation: Part 1 — Theory

2004 ◽  
Author(s):  
Rene´ H. Christensen ◽  
Ilmar F. Santos
Keyword(s):  
Vibration Control ◽  
Rotor Blade ◽  
Controller Design ◽  
Design Procedure ◽  
Magnetic Actuation ◽  
Blade Vibration ◽  
Rotor Systems ◽  
Electro Magnetic ◽  
Vibration Coupling ◽  
Controllability And Observability

This is the first paper in a two-part study on active rotor-blade vibration control using electro-magnetic actuation. Emphasis is focused on theoretical aspects of implementing active control into coupled rotor-blade systems, more precisely, into systems where rotor lateral motion is coupled to blades flexible motion. The theoretical investigation includes controllability and observability analyses of such a system in order to determine optimal actuator and sensor placement. An analysis methodology based on modal analysis in time-variant systems, due to the periodic time-variant nature of this kind of system, is presented. The method takes into account the strong vibration coupling which has a significant effect on the controllability and observability of bladed rotor systems. The analyses show that, for tuned bladed rotors, actuators will have to be located within the blades in order to make all vibration modes controllable. However, if the system is deliberately mistuned, rotor and blade vibrations can be controlled using shaft-based actuation and sensing only. Moreover, a controller design procedure for obtaining active periodic time-variant modal controllers, capable to cope with the time-periodicity of the system, is presented. Controllers are designed for a tuned as well as a deliberately mistuned system. The tuned system is controlled using both blade and shaft actuators while the mistuned system is controlled using only shaft actuation. Numerical simulations are provided to show the efficiency of the designed controllers.

An improved dynamic load-strength interference model for the reliability analysis of aero-engine rotor blade system

2020 ◽  
pp. 095441002097289
Author(s):  
Bingfeng Zhao ◽  
Liyang Xie ◽  
Yu Zhang ◽  
Jungang Ren ◽  
Xin Bai ◽  
...  
Keyword(s):  
Reliability Analysis ◽  
Dynamic Load ◽  
Rotor Blade ◽  
Engineering Application ◽  
Weight Ratio ◽  
System Component ◽  
Aero Engine ◽  
Blade System ◽  
Improved Model ◽  
Engine Rotor

As the power source of an aircraft, aero-engine tends to meet many rigorous requirements for high thrust-weight ratio and reliability with the continuous improvement of aero-engine performance. In this paper, based on the order statistics and stochastic process theory, an improved dynamic load-strength interference (LSI) model was proposed for the reliability analysis of aero-engine rotor blade system, with strength degradation and catastrophic failure involved. In presented model, the “unconventional active” characteristic of rotor blade system, changeable functioning relationships and system-component configurations, was fully considered, which is necessary for both theoretical analysis and engineering application. In addition, to reduce the computation cost, a simplified form of the improved LSI model was also built for convenience of engineering application. To verify the effectiveness of the improved model, reliability of turbojet 7 engine rotor blade system was calculated by the improved LSI model based on the results of static finite element analysis. Compared with the traditional LSI model, the result showed that there were significant differences between the calculation results of the two models, in which the improved model was more appropriate to the practical condition.

scholarly journals A Nonintrusive Rotor Blade Vibration Monitoring System

1996 ◽  
Author(s):  
Henry Jones
Keyword(s):  
Rotor Blade ◽  
Rotating Machinery ◽  
Vibration Monitoring ◽  
Static Deflection ◽  
Blade Vibration ◽  
Turbine Engine ◽  
Measurement Systems ◽  
Timing Data ◽  
On Line ◽  
Engine Rotor

A technique for measuring turbine engine rotor blade vibrations has been developed as an alternative to conventional strain-gage measurement systems. Light probes are mounted on the periphery of the engine rotor casing to sense the precise blade passing times of each blade in the row. The timing data are processed on-line to identify (1) individual blade vibration amplitudes and frequencies, (2) interblade phases, (3) system modal definitions, and (4) blade static deflection. This technique has been effectively applied to both turbine engine rotors and plant rotating machinery.

Wet Steam Nonequilibrium Condensation Flow-Induced Vibrations of a Nuclear Turbine Blade

2018 ◽  
Vol 140 (11) ◽  
Author(s):  
Bing Guo ◽  
Weixiao Tang
Keyword(s):  
Rotor Blade ◽  
Virtual Work ◽  
Pressure Fluctuations ◽  
Tangential Component ◽  
Axial Component ◽  
Flow Induced Vibration ◽  
Blade Vibration ◽  
Vibration Responses ◽  
Nonequilibrium Condensation ◽  
Equivalent Load

Condensing flow induced vibration (CFIV) of the rotor blade is a tough problem for designers of nuclear turbines because nonequilibrium condensing flow excitation (NECFE) is hard to be directly modeled. Generally, in design, NECFE is assumed as equilibrium condensing flow excitation (ECFE), of which the pressure fluctuations caused by phase temperature difference (PTD) between gaseous and liquid are ignored. In this paper, a novel method to calculate the equivalent load of NECFE based on the principle of virtual work was proposed. This method could consider the effects of PTD-induced pressure fluctuations by simulating nonequilibrium condensation with ANSYS cfx, and improve computational efficiency. Once the equivalent NECFE load is determined, CFIV of the rotor blade, which was modeled as a pretwisted asymmetric cantilever beam, can then be predicted by the finite element method (FEM). Additionally, to estimate the effects of PTD-induced pressure fluctuations, comparisons between NECFE and ECFE as well as their induced vibrations were presented. Results show that PTD in nucleation area could change the position and type of shock waves, restructure the pressure distribution, as well as enhance the pressure fluctuations. Compared with ECFE, the frequency ingredients and amplitude of the equivalent NECFE load and its induced vibrations are increased. Specifically, the amplitude of the equivalent NECFE load is increased by 9.38%, 15.34%, and 7.43% in the tangential component, axial component, and torsion moment. The blade vibration responses induced by NECFE are increased by 11.66% and 19.94% in tangential and axial.

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