Schlussbericht ExpTurb: Design einer Experimentalturbine

Das DLR entwickelt die "Plattform Windenergie", wovon die Errichtung mehrerer Windenergieanlagen wesentlicher Bestandteil ist. Eine diese Anlagen ist die als modularer Versuchsträger konzipierte Experimentalturbine. Sie soll der Validierung von Methoden und Modellen sowie die Erprobung von Technologien dienen. Ziel des Projekts war die Entwicklung eines entsprechenden Anlagendesigns. Das Ergebnis sind Dokumente, Daten und numerische Modelle, die diese einzigartige Experimentalturbine beschreiben. Das Design der pitchgesteuerten Anlage mit 500 kW Nennleistung wurde durch ein erfahrenes Ingenieurbüro von einem bewährten kommerziellen Entwurf abgeleitet. Seine Besonderheit liegt in der konsequenten Entwicklung für die Erforschung des Rotors der Zukunft. Daher umfasst das Design ein eigens entwickeltes sehr schlankes Rotorblatt, das die Vergleichbarkeit mit der Aerodynamik aktueller Multi-MW-Anlangen herstellt, hohe Schnelllaufzahlen ermöglicht und eine wechselbare Blattspitze besitzt. Die Anlagengröße war ebenso ein Designkriterium wie der Zugang zu allen Baugruppen. Ein besonders dynamisches Pitchsystem und eine Lidar-Plattform auf dem Gondeldach sind weitere Merkmale. Die Experimentalturbine ist durch die Kombination dieser Eigenschaften ein besonderer Versuchsträger für Experimente zur Untersuchung der Aerodynamik, Aeroakustik, Aeroelastik, Regelung und Meteorologie von Windenergieanlagen

An open-source framework for the uncertainty quantification of aeroelastic wind turbine simulation tools

The uncertainty quantification of aeroelastic wind turbine simulations is an active research topic. This paper presents a dedicated, open-source framework for this purpose. The framework is built around the uncertainpy package, likewise available as open source. Uncertainty quantification is done with a non-intrusive, global and variance-based surrogate model, using PCE (i.e., polynomial chaos expansion). Two methods to handle the uncertain parameter distribution along the blades are presented. The framework is demonstrated on the basis of an aeroelastic stability analysis. A sensitivity analysis is performed on the influence of the flapwise, edgewise and torsional stiffness of the blades on the damping of the most critical mode for both a Bladed linearization and a Bladed time domain simulation. The sensitivities of both models are in excellent agreement and the PCE surrogate models are shown to be accurate approximations of the true models

Wind turbine stability: Comparison of state-of-the-art aeroelastic simulation tools

As rotor diameters and blade flexibility are increasing, current and future generation wind turbines are more susceptible to aeroelastic instabilities. It is thus important to know the prediction capabilities of state-of-the-art simulation tools in regards of the onset of aeroelastic instability. This article presents results of a code-to-code comparison of five different simulation codes using a representative wind turbine model. It is shown that the models are in good agreement in terms of isolated structural dynamics and steady state aeroelastics. The more complex the test cases become, the more significant are the differences in the results. In the final step of comparison, the aeroelastic stability limit is determined through a run-away analysis. The instability onset is predicted at different wind speeds and the underlying mechanisms differ between the tools. A Campbell diagram is used to correlate the findings of time domain simulation tools with those of a linear analysis in the frequency domain

Retrospective evaluation of whole exome and genome mutation calls in 746 cancer samples

Funder: NCI U24CA211006Abstract: The Cancer Genome Atlas (TCGA) and International Cancer Genome Consortium (ICGC) curated consensus somatic mutation calls using whole exome sequencing (WES) and whole genome sequencing (WGS), respectively. Here, as part of the ICGC/TCGA Pan-Cancer Analysis of Whole Genomes (PCAWG) Consortium, which aggregated whole genome sequencing data from 2,658 cancers across 38 tumour types, we compare WES and WGS side-by-side from 746 TCGA samples, finding that ~80% of mutations overlap in covered exonic regions. We estimate that low variant allele fraction (VAF < 15%) and clonal heterogeneity contribute up to 68% of private WGS mutations and 71% of private WES mutations. We observe that ~30% of private WGS mutations trace to mutations identified by a single variant caller in WES consensus efforts. WGS captures both ~50% more variation in exonic regions and un-observed mutations in loci with variable GC-content. Together, our analysis highlights technological divergences between two reproducible somatic variant detection efforts

Blade model comparison based on static and modal test scenarios

Wind turbine rotors are getting larger in diameter to increase the output of a single turbine and reduce the cost of energy production. The increase in size leads to complex structure-mechanical effects that have to be considered in order to design the wind turbine blade in a reasonable way. Currently many models exist that are able to represent these effects. Usually, a compromise between accuracy and simulation speed has to be made. The analysis of a wind rotor blade is divided into two parts. The turbine simulation and the detailed analysis. Modally reduced models or beam model descriptions are used in aeroelastic turbine simulations for load calculations and pre-design. The final sizing takes place in a more detailed finite element model. Depending on the application, the models differ in complexity, which ultimately affects the computational effort of their solution

Comparison of Unsteady Low- and Mid-Fidelity Propeller Aerodynamic Methods for Whirl Flutter Applications

Aircraft configurations with propellers have been drawing more attention in recent times, partly due to new propulsion concepts based on hydrogen fuel cells and electric motors. These configurations are prone to whirl flutter, which is an aeroelastic instability affecting airframes with elastically supported propellers. It commonly needs to be mitigated already during the design phase of such configurations, requiring, among other things, unsteady aerodynamic transfer functions for the propeller. However, no comprehensive assessment of unsteady propeller aerodynamics for aeroelastic analysis is available in the literature. This paper provides a detailed comparison of nine different low- to mid-fidelity aerodynamic methods, demonstrating their impact on linear, unsteady aerodynamics, as well as whirl flutter stability prediction. Quasi-steady and unsteady methods for blade lift with or without coupling to blade element momentum theory are evaluated and compared to mid-fidelity potential flow solvers (UPM and DUST) and classical, derivative-based methods. Time-domain identification of frequency-domain transfer functions for the unsteady propeller hub loads is used to compare the different methods. Predictions of the minimum required pylon stiffness for stability show good agreement among the mid-fidelity methods. The differences in the stability predictions for the low-fidelity methods are higher. Most methods studied yield a more unstable system than classical, derivative-based whirl flutter analysis, indicating that the use of more sophisticated aerodynamic modeling techniques might be required for accurate whirl flutter prediction

Framework for uncertainty quantification of aeroelastic wind turbine simulations

Framework for uncertainty quantification of aeroelastic wind turbine simulations. The code for a case study on the influence of blade beam properties on the wind turbine aeroelastic stability is available with interfaces to multiple aeroelastic tools. The framework is a wrapper around the uncertainpy package which provides methods for surrogate model based uncertainty quantification

Comparison of state-of-the-art aeroelastic simulation tools for wind turbines

Increasing rotor diameter and a flexible lightweight blade structure – this combination is characteristic for recent and future generations of wind turbines. Complex interactions with the support structure of the turbine and the environment result in challenging aeroelastic properties. This raises the question whether current simulation tools are comparable in their ability of predicting the behaviour of modern wind turbine rotor designs. The talk summarizes a code-to-code comparison between two commercial general purpose multi body systems with wind turbine specific extensions (SIMPACK and alaska/Wind) and three established turbine simulation tools (Bladed, FAST, HAWC2). To this end the publicly available reference wind turbine IWT-7.5-164 model has been adapted for the considered tools, with slight modifications in the airfoil polars. The comparison itself is a thorough cross-check between the five simulation codes. The corresponding tests were defined with increasing model complexity, ranging from the static elastic deformation of a single blade fixed at the root to the dynamic response of the wind turbine model subjected to homogeneous wind inflow. Whenever possible, the results were complemented by simulations of additional codes.This work was conducted as a collaboration of four partners from research and industry in the frame of work package 4.2 of the German national research project SmartBlades2. This project is funded by the German Federal Ministry for Economic Affairs and Energy, grant no. 0324032 A/C

Code-to-code comparison of realistic wind turbine instability phenomena

Preceding studies (Hach et al, 2020) show significant differences in the prediction of dynamic aeroelastic instabilities with state-of-the-art simulation tools. Instabilities were provoked by an overspeed scenario where the wind speed increases, but no counteracting generator moment was imposed. Significant differences between the tools were found in the critical speed and instability behavior. A negative side effect of the runaway procedure is that the operating conditions at which the instability occurred could be vastly different. Differences in the instability mechanisms could therefore be in part allocated to these differing operating conditions. The aim of this study is to find a critical configuration model which becomes unstable under nominal, controlled operating conditions. The expectation was that the establishing instability mechanism would be more representative for potential aeroelastic phenomena which could be experienced on current or future turbines (Volk et al, 2020). State-of-the-art simulation models are used to give insight in the instability phenomena and to compare their respective modeling capabilities. These included two general purpose multi-body simulation tools (alaska/Wind and Simpack) and three industry relevant turbine simulation tools (Bladed, HAWC2, OpenFAST). Simulations were executed both in the time domain (all tools) and in the frequency domain (Bladed and HAWCStab2). The publicly available reference wind turbine model IWT-7.5-164 served as reference for the comparison. The global flapwise, edgewise and torsional stiffnesses were reduced over the full blade to enforce instabilities under nominal operating conditions. A recomputation of the stiffness matrices was performed with the adjusted input in order to assure equivalent stiffness reductions across all tools. Consistency across the models was verified by a blade and full model modal analysis, static structural deformation tests and a steady aeroelastic deformation test. The final stability analysis was performed for multiple points along the nominal control curve. Unstable time domain simulations were analyzed by a frequency analysis to determine the instability mechanism. This also allowed a comparison between the time domain and the frequency domain simulation tools. A comparison is shown for the aeroelastic modes which play a role in the instability mechanisms. The agreement between the linearization results of Bladed and HAWCStab2 is satisfying. All simulation tools exhibit comparable unstable behavior with a significant participation of the 1st and/or 2nd edge bending modes of the blades. Large differences are observed between critical wind speeds in the time domain simulation results. Preliminary analyses reveal discrepancies in the damping associated with the vibrations. The presented comparison demonstrates that the observed instability mechanism matches across the aeroelastic simulation tools if the operating conditions are close enough - which is not always the case in a runaway analysis. To provoke an instability in the normal operating range the stiffness of the rotor blades was decreased significantly. It was found that the stiffness matrices needed to be re-computed since independently reducing the principle stiffnesses in flap/edge/torsion leads to inconsistent models

Deliverable D9.1 Use case specification, development, installation, commissioning, demonstration, and evaluation planning for the Danish demo

This deliverable consolidates the final specifications for the Use Cases (UCs) to be demonstrated in Denmark. The deployment plan includes an initial assessment of the current infrastructure at both locations, i.e., Risø and Campus Bornholm. Risø is a research campus of the Technical University of Denmark (DTU) and located in Roskilde, while Campus Bornholm is an educational institute in the main town Rønne on the island of Bornholm. Based on the assessment of both locations, the present document presents a detailed description of hardware and software that will be implemented, and the associated construction works required for their deployment.The Electric Vehicle (EV) charging infrastructure is identical at both locations and comprises six Alternating Current (AC) chargers (22 kW), respectively. Each of the six AC chargers has two outlets, providing the opportunity for twelve EVs to be connected at the same time. The charging infrastructure is integrated via a 43 kW grid connection, and operated through a load management system enabling the maintenance of aggregated consumption below a specified threshold. This offers various benefits, e.g., preventing component overloading or the provision of both local and external services, such as peak shaving, increasing self-sufficiency, and frequency control.Each charger deployed in this project is equipped with a controller that enables the charger to make autonomous control decisions. This facilitates distributed control schemes where all chargers are provided with global quantities, such as the cluster reference power and the actual cluster consumption, based on which all chargers individually control their respective charging session to collectively meet the cluster requirements.Users of the charging infrastructure will start their charging sessions through an app, which is developed as part of the EV4EU project. The app allows the user to provide key inputs, such as the anticipated parking time and the required energy, which enable the load management system to consider user preferences while controlling the overall cluster consumption. The data acquisition and logging further include high-resolution power measurements at each charger, and of the overall cluster consumption through a dedicated meter at the point of common coupling (PCC).Moreover, the deliverable proposes 19 Key Performance Indicators (KPIs) for quantifying the performance and impact of the demonstration activities. The KPIs are organized in four main categories, addressing economic, technical, user related, and environmental impacts. Finally, the document summarizes the current status of the infrastructure deployment and gives an outlook for the upcoming tasks within the Danish demonstration. Specifically, Task 9.2 will finalize the already well-advanced deployment and commissioning of the charging infrastructure at both locations, followed by the start-up of operation