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Project
virtual prototyping for vibro-acoustic assessment of windturbine drivetrains
This dissertation describes the development of a methodology and modelling approach to lower the mechanical noise of the drive train of a modern wind turbine with a strong focus on the wind turbine gearbox. Althoughthis mechanical noise is not the main noise source from a wind turbine,it could - especially when it contains audible tonal components - result in non-conformity to local noise regulations. This becomes more stringent when wind turbines are installed closer to urbanised areas. This research is motivated by inefficiencies in a cost and time consuming reactive trial and error approach to reduce or remove audible mechanical tonalities from the wind turbine noise.
This dissertation focusses on the mechanical tonalities linked with the wind turbine gearbox. This mechanical noise originates from the interaction between the gears inside the gearbox, and then propagates directly airborne through the air or indirectly structure-born through the other wind turbine components to the outside. Two fundamental approaches exist to reduce or to remove amechanical tonality. The first approach attempts to reduce the noise source by optimising the gears for low-noise. The second approach modifiesthe propagation path, also called transfer path from the source to the listener, such that the noise originating from the noise source is not amplified or even attenuated when it reaches the listener. The methodology proposed in this dissertation focusses on the second approach: using virtual prototyping models to assess and to optimise these transfer paths.
The development of this methodology consists of 3 main parts: firstly individual components of the wind turbine gearbox are investigated in detail and if necessary experimentally validated. Secondly these individual components are assembled into a wind turbine gearbox model. The impact of these individual components on the global eigenmodes ofthe gearbox are investigated, and the model of the complete gearbox is experimentally validated by performing an experimental modal analysis. Lastly a model of two gearboxes on the end-of-line test rig is generated,investigated and also experimentally validated. This step-by-step approach, including the numerous experimental validation cases, resulted in asignificant increase in both insight and confidence in the dynamic behaviour predicted by these virtual prototyping models.
This dissertation demonstrates this methodology and modelling approach by performing two optimisation cases. The first optimisation case focusses on the impact of the bearings on the resulting vibrations. The second optimisation case modifies the flexible gearbox housing, which is considered the most dominant component, to shift an important eigenmode out of the operating range of the wind turbine. Both these optimisation cases clearly illustrate the potential of pro-actively using virtual simulation models to optimise the noise and vibration behaviour of the wind turbine gearbox during its design.
This dissertation focusses on the mechanical tonalities linked with the wind turbine gearbox. This mechanical noise originates from the interaction between the gears inside the gearbox, and then propagates directly airborne through the air or indirectly structure-born through the other wind turbine components to the outside. Two fundamental approaches exist to reduce or to remove amechanical tonality. The first approach attempts to reduce the noise source by optimising the gears for low-noise. The second approach modifiesthe propagation path, also called transfer path from the source to the listener, such that the noise originating from the noise source is not amplified or even attenuated when it reaches the listener. The methodology proposed in this dissertation focusses on the second approach: using virtual prototyping models to assess and to optimise these transfer paths.
The development of this methodology consists of 3 main parts: firstly individual components of the wind turbine gearbox are investigated in detail and if necessary experimentally validated. Secondly these individual components are assembled into a wind turbine gearbox model. The impact of these individual components on the global eigenmodes ofthe gearbox are investigated, and the model of the complete gearbox is experimentally validated by performing an experimental modal analysis. Lastly a model of two gearboxes on the end-of-line test rig is generated,investigated and also experimentally validated. This step-by-step approach, including the numerous experimental validation cases, resulted in asignificant increase in both insight and confidence in the dynamic behaviour predicted by these virtual prototyping models.
This dissertation demonstrates this methodology and modelling approach by performing two optimisation cases. The first optimisation case focusses on the impact of the bearings on the resulting vibrations. The second optimisation case modifies the flexible gearbox housing, which is considered the most dominant component, to shift an important eigenmode out of the operating range of the wind turbine. Both these optimisation cases clearly illustrate the potential of pro-actively using virtual simulation models to optimise the noise and vibration behaviour of the wind turbine gearbox during its design.
Date:8 Sep 2009 → 21 Jan 2015
Keywords:Windturbine
Disciplines:Control systems, robotics and automation, Design theories and methods, Mechatronics and robotics, Computer theory
Project type:PhD project