Beurteilung von Korrosionsschutzsystemen für Offshore‐Windenergietürme – Teil 2: Ergebnisse und Schlussfolgerungen

Im Rahmen von Auslagerungs‐ und Laborprüfungen wurde die Korrosionsschutzwirkung verschiedener, für den Schutz von Offshore‐Windenergietürmen geeigneter Systeme untersucht. Zu den untersuchten Systemen gehörten Duplexsysteme mit Zn/Al‐Metallisierung, mehrschichtige organische Systeme, ein einschichtiges organisches System, eine Zn/Mg‐Metallisierung sowie unbeschichtete Bereiche mit kathodischem Korrosionsschutz. Alle Systeme wurden an speziell gefertigten Auslagerungsprobekörpern sowie an Laborprobekörpern geprüft. Die im Labormaßstab durchgeführten Prüfungen umfassten Tauchversuche, Alterungsversuche, Versuche zur kathodischen Verträglichkeit und Messungen mittels elektrochemischer Impedanzspektroskopie. Im Teil 1 des Beitrages, veröffentlicht im Heft 4/2009, wurden Konzeption und Durchführung der Prüfungen sowie die verwendeten Probekörper und Korrosionsschutzsysteme detailliert beschrieben. Über die Ergebnisse der Prüfungen wird im Teil 2 berichtet. Assessment of corrosion protection systems for offshore wind energy towers – part 2: Results and conclusions. Based on field and on laboratory tests, the corrosion protective performance of different corrosion protection systems for offshore wind energy towers was investigated. The systems under investigation included duplex systems with Zn/Al metallization, multi‐layered organic systems, a single‐layer thick organic system, Zn/Mg metallization and cathodic protection of uncoated sections. Special field specimens and laboratory specimens were utilized in order to investigate the systems. Laboratory tests included immersion tests, ageing tests, test on cathodic compatibility and electro‐chemical impedance spectroscopy. Part 1 of the paper (Stahlbau, No. 4/2009) covererd the general experimental design and details of the experimental procedures, whereas Part 2 deals with the results of the test programme.     

Beurteilung von Korrosionsschutzsystemen für Offshore‐Windenergietürme – Teil 1: Problemstellung und Versuchsdurchführung

Assessment of corrosion protection systems for offshore wind energy towers – part 1: Introduction and test scenario. Based on field and on laboratory tests, the corrosion protective performance of different corrosion protection systems for offshore wind energy towers was investigated. The systems under investigation included duplex systems with Zn/Al metallization, multi‐layered organic systems, a single‐layer thick organic system, Zn/Mg metallization and cathodic protection of uncoated sections. Special field specimens and laboratory specimens were utilized in order to investigate the systems. Laboratory tests included immersion tests, ageing tests, test on cathodic compatibility and electro‐chemical impedance spectroscopy. Part 1 of the paper covers the general experimental design and details of the experimental procedures, whereas Part 2 deals with the results of the test programme.     

非饱和土水气两相渗流有限元数值模型

根据非饱和土水气两相渗流理论,用Galerkin法建立了用以计算非饱和土水气两相渗流流场的有限元计算模型,编制了三维有限元计算程序,并介绍了该计算模型在可挥发污染物抽气曝气组合清除法中的应用。     

采空区瓦斯与大气两相混溶扩散模型及其求解

基于两相混溶气体渗流一扩散方程，建立了非均质采空区瓦斯涌出与风流交换的模型，用迎风式Galerkin数值方法求解，以可视化方式直观描绘了回采中采空区瓦斯的运移与分布的流体力学原理，采空区瓦斯源用负指数衰减函数描述。在力学处理上，对不透气顶、底板采空区的瓦斯涌出用可压缩两相气体混溶来考虑，流态（速度场）计算则用不可压缩气体渗流求解，由此可克服了以往采用不可压缩气体渗流一扩散模型计算瓦斯分布结果中因“超饱和”解所带来的误差和失真问题。给出增大风量后瓦斯分布的算例，由此反映出工作面风压与采空区内部瓦斯压力的动态平衡性。与单相流计算结果对比，在风流流速相对较高的情况下，两者的瓦斯分布结果基本一致，反之则差别很大，算例中开始出现差别的临界风速为0．091m／min，在采空区深部处瓦斯分布显著不同。     

A model of reaeration rates driven by shear flows

The reaeration rate determines the speed that the dissolved oxygen is restored to the saturation level. The reaeration rate is determined by the surface renewal rates from the friction interfaces in the water bodies, including the water/bed interface, the shear‐flow interface and the air/water interface. The formulae of reaeration rate for the air/water interface and the water/bed interface were developed in prior studies. However, no formula of the reaeration rate driven by the shear flows was developed. In this study, a mechanic model of the reaeration rate driven by the shear flows is developed to fill in the gap. The flow velocity profile in the shear flows and the Surface Renewal Theory are employed to derive the corresponding model. The predictions of the formulae for these three types of friction interfaces are compared for the same phase velocity to investigate the reasonability of the reaeration rate model for the shear‐flow interface. The predictions of the model for the shear‐flow interface are between those for the air/water interface and for the water/bed interface. The model in this study is also verified to have reasonable agreements with the experimental data. The model developed in this study can be applied for the prediction of the low soluble gases’ transfer rate between air and water in shear flows.     

Erste Erfahrungen bei der Realisierung der Tragstrukturen von Offshore‐Windenergieanlagen in der deutschen ausschließlichen Wirtschaftszone

First experience with the realisation of substructures for Offshore Wind turbines in the German Exclusive Economic Zone. A considerable part of the power demand in Germany shall be covered in the future through the installation and operation of offshore windfarms in the Exclusive Economic Zone. The responsible public authority, the Federal Maritime and Hydrographic Agency, has published a set of standards for the production and installation of the wind turbines. This paper discusses the contents of the standards concerning the steel constructions for the wind turbines. Special attention is given to the phases of the approval process and their different parts, as well as to the legal requirements with respect to the type and extent of assessments for the supporting structure. The first experience for the installation of windfarms are being evaluated currently by the public authorities. The resulting conclusions from the point of view of the public agents and their consultants are also discussed in this paper, with special focus and hints on the controversial points.     

海上单桩风机结构冰激振动响应分析

针对冰区海上单桩风机易发生冰激振动的问题,以NREL5MW风机为对象,详细开展其在风-冰联合作用下的动力响应研究.基于叶素动量理论,考虑Prandtl叶尖损失修正和Grauert修正,利用MATLAB编程计算获得叶片空气动力载荷;基于M??tt?nen自激振动模型,采用APDL开发冰区风机自激振动分析程序;基于我国渤海...