Site specific simulation of ice shed and ice throw from wind turbines using ballistic models
Abstract
Wind energy will play a crucial role in the future Austrian energy mix. Currently, the increase in wind energy production is severely limited by the fact that most favorable areas have al-ready been put to use. Even the existing exchange of older plants with new, more efficient ones (repowering) at favorable sites is not sufficient with regard to the political objective. Thus, there is a strong interest in technically more demanding sites, such as forests and alpine areas. The importance of risk assessments for ice shed or ice throw also increases with higher terrain complexity and/or icing frequency. These assessments usually rely on ballistic models to calculate shed or throw distances. However, the models currently used have significant weaknesses. The comparison between experiments and model calculations shows that no model can satisfactorily reproduce the shed distances. Furthermore, no reliability limits are given for the existing models, which means that for safety reasons considerably higher distances from wind power plants to infrastructures have to be selected. Finally, the applied simulation programs were mostly designed for flat or evenly inclined terrain; more complex terrains are not at all or at best poorly represented. The present project addresses these problems by developing a novel model including associated simulation tools. The data basis consists of observations and results from 1:1 experiments. The latter have the decisive advantage of allowing large sample numbers to be generated in a weather-independent manner- a prerequisite for statistically significant statements. In the experiments, test specimens are dropped or thrown from wind turbines. These specimens are based on 3D-scans of real ice fragments, which were collected and digitized in previous projects. Using a 3D-printing process, these are reproduced with suitable density and in sufficient number. This is an entirely novel approach since no other actor in this research field uses a similar method. The feasibility of these studies was demonstrated by the project leader in previous projects and suitable devices were developed. The model itself is based on a model with six degrees of freedom (6DOF), allowing for all possibilities of translation and rotation. Compared to other models, additional forces from autorotation are taken into account in addition to the flow resistance. The necessary parameters are determined by computational fluid dynamics (CFD). The model is embedded in a simulation environment that takes into account both fractures of the ice fragments during the fall, as well as complex terrain. The developed tool not only enables improved safety assessments, but also derivations for technological adaptations and optimization of wind turbines to specific site conditions. It should be emphasized that the improved safety assessments and validated limits for icefall and ice throw allow the development of new sites, which currently can only be used to a limited extent or not at all, due to excessively conservative safety distances.
wind energy wind power risk ice shed ice throw icing
Publikationen
Project staff
Markus Drapalik
Mag. Dr. Markus Drapalik
markus.drapalik@boku.ac.at
Tel: +43 1 47654-81811
Project Leader
01.05.2018 - 31.03.2021
Friederike Frieß
Dr.rer.nat. Friederike Frieß
friederike.friess@boku.ac.at
Tel: +43 1 47654-81821
Project Staff
01.05.2018 - 31.03.2021
Wolfgang Liebert
Univ.-Prof. i.R. Dipl.-Phys. Dr.phil.nat. Wolfgang Liebert
liebert@boku.ac.at
Tel: +43 1 47654-81814
Project Staff
01.05.2018 - 31.03.2021
Nikolaus Müllner
Mag. Dr. Nikolaus Müllner
nikolaus.muellner@boku.ac.at
Tel: +43 1 47654-81801, 81820
Project Staff
01.05.2018 - 31.03.2021
Sebastian Purker
Sebastian Purker B.Sc.
sebastian.purker@boku.ac.at
Tel: +43 1 47654-81823
Project Staff
01.05.2018 - 31.03.2021
BOKU partners
External partners
WEB Windenergie AG
none
partner
Energie Burgenland Windkraft _x000D_
none
partner