新型海上风机浮式基础设计与风机系统耦合动力分析

发布时间：2018-01-11 09:26

本文关键词：新型海上风机浮式基础设计与风机系统耦合动力分析　出处：《天津大学》2014年博士论文　论文类型：学位论文

【摘要】：本文结合我国发展需求，展开了关于浮式海上风机的研究。在五十米至八十米水深的深海和浅海间的过度海域，，传统的Spar式浮式基础由于吃水过深、排水体积过大而不再适用。为了利用该海域的海上风能，减少海上风能成本，本文设计了一种新型海上风机浮式基础。针对该浮式基础，本文建立了风机-塔柱-基础-系泊线耦合的分析模型，对其施加包括二阶波浪力在内的水动力载荷及空气动力载荷，开发了一种耦合动力响应预报的数值工具。为了研究二阶差频波浪力对浮式基础运动响应的重要性，研究工作建立了一阶和二阶两种耦合分析模型，并对数值工具的模拟能力进行验证。运用本文开发的数值工具，研究工作对所设计的新型浮式基础的六个自由度响应进行了空气动力-水动力时域耦合分析。根据海上风机作业情况，使用一阶和二阶模型分别模拟海上风机在工作和自存两种海况下的运动，分析二阶差频波浪力对浮式基础运动响应的影响，以及浮式基础在不同载荷作用下的运动性能。通过对比运动响应的时间历程、响应谱和缆绳张力的统计值，可以发现二阶波浪力对海上风机运动响应和缆绳受力有明显作用，计算中不应忽略，否则可能会影响海上风机的作业和自存安全。其中工作海况下由于存在风机的空气动力载荷，主导了运动响应，因此二阶波浪力的作用没有自存海况下显著。海上风机受到水动力载荷和风载荷的联合作用，受力复杂，环境载荷的入射方向会对运动响应造成影响，为了研究风机系统在不同方向环境载荷作用下的响应情况，本文进行了五个入射角的模拟分析，分别对比了入射角在工作海况和自存海况下对运动响应的影响。由于风机在作业时控制系统会对叶片桨距角进行调节，使发电机保持额定功率。当控制系统发生故障时会出现叶片桨距角失衡情况，它是发电机转轴扭矩发生激增的重要原因之一。在对控制系统失效的事故情况模拟后，通过与正常作业情况的六个自由度响应时间历程和响应谱进行对比，发现桨距角失衡主要激发了浮式基础横向的响应，它与横荡、横摇和首摇更相关。同时可以看到这三个方向上变桨失效后明显的瞬时响应。在叶片桨距角出现故障时，在转子旋转频率和二倍频率上横摇和首摇方向出现激振，相应地，塔柱底部的横向载荷有重要的变化。
[Abstract]:According to the development demand of our country, the research on floating offshore fan is carried out in this paper. In the deep sea with 50 meters to 80 meters depth and in the transitional sea between shallow water and water depth, the traditional Spar floating foundation is due to the deep draught. In order to make use of offshore wind energy and reduce the cost of offshore wind energy, a new floating foundation of offshore fan is designed in this paper. Aiming at the floating foundation, an analytical model of the coupling of blower, tower column, foundation and mooring line is established, and the hydrodynamic load and aerodynamic load including second-order wave force are applied to the model. A numerical tool for predicting coupled dynamic response is developed. In order to study the importance of second-order differential wave force to the motion response of floating foundation, the first and second order coupled analysis models are established. The simulation ability of the numerical tool is verified. Using the numerical tools developed in this paper, the aerodynamic and hydrodynamic time domain coupling analysis of the six degrees of freedom response of the new floating foundation is carried out. The first and second order models are used to simulate the motion of the offshore fan under two sea conditions, the second order differential wave force and the dynamic response of floating foundation. And the movement performance of floating foundation under different loads. By comparing the time course of motion response, response spectrum and cable tension statistical value. It can be found that the second-order wave force has obvious effect on the motion response of offshore fan and cable force, which should not be ignored in calculation. Otherwise, it may affect the operation and self-storage safety of offshore fan, in which the action of second-order wave force is not significant under sea condition because of the aerodynamic load of fan. The offshore fan is subjected to the combined action of hydrodynamic load and wind load, and the force is complex, and the direction of incidence of the environmental load will affect the motion response. In order to study the response of fan system under different directions of environmental load, five incident angles are simulated and analyzed in this paper. The effect of incident angle on the motion response is compared under the working sea condition and the self-stored sea condition respectively. Since the fan control system will adjust the blade pitch angle in operation, the generator will maintain rated power. When the control system fails, the blade pitch angle will be out of balance. It is one of the important reasons for the surge of generator shaft torque. After simulating the failure of the control system, the response time history and response spectrum of six degrees of freedom are compared with the normal operating conditions. It is found that the pitch angle imbalance mainly excites the lateral response of the floating foundation, which is related to the swinging. Roll and pitch are more related. At the same time, the obvious instantaneous response after the failure of the propeller in these three directions can be seen. In the rotor rotation frequency and the double frequency, the rolling and the first shaking direction are excited. Accordingly, the lateral load at the bottom of the tower column has important changes.
【学位授予单位】：天津大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：TM315;TU476.1

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