兆瓦级垂直轴风力机传动轴系与制动系统研究

发布时间：2018-06-20 16:48

本文选题：垂直轴风力发电机 + 兆瓦级　；参考：《哈尔滨工业大学》2017年硕士论文

【摘要】：作为大型垂直轴风力发电机的重要组成部分,传动系统和制动系统对整个风电机组的运行和安全起着至关重要的作用。目前市场上大功率垂直轴风力机所占份额很少,对于大功率垂直轴风力机的传动系统尚无固定的设计体系,而且多数垂直轴风力机无变桨系统,随之而来的问题是所需的机械制动力矩很大。为解决此问题,本文将对兆瓦级垂直轴风力机的传动系统及制动系统进行研究。为了解决兆瓦级垂直轴风力机传动系统设计的困难,对比了多种风力机传动方案,确定了一种最优传动结构方案:整机为半直驱传动形式,将增速器、发电机等置于地面附近安装布置;轴承方案采用三级轴承支承,主轴承(Ⅰ级轴承)为转盘轴承,上导轴承(Ⅱ级轴承)为调心滚子轴承,下导轴承(Ⅲ级轴承)为推力调心滚子轴承,上导轴承和下导轴承均采用剖分式轴承。为了获得风力机在不同工况下的载荷,采用Fluent数值模拟的方法对风轮进行了气动特性的计算,并根据载荷确定了传动轴各段轴的结构尺寸。为使轴系结构满足设计要求,对其进行了强度校核、疲劳分析和模态分析。为了解决大功率风力机制动可靠的问题,建立了制动系统模型,对安装在不同位置的制动器进行了受力分析。针对不同的制动工况,对机械制动系统的方案进行了制动力矩及制动时间等相关计算,确定了高速轴+低速轴两级制动方案,并利用ANSYS软件对制动器摩擦副进行了温度场及应力场的分析。采用等时间间隔的循环加载热流密度的方法,分别对额定风速下正常制动工况和弃风风速下紧急制动工况时低速轴和高速轴的摩擦副温度场进行模拟计算。结果表明,制动盘温度分布不均匀,高温区主要集中在摩擦接触表面。制动衬片温度相较制动盘高出很多,表面温度分布较均匀。两种工况下制动盘和制动衬片温度分布相似,紧急工况温度相对较高。对制动器分别进行了纯机械应力分析和热应力分析。通过应力场分析,可以判断制动盘是否会产生热裂纹或者失效,为制动盘的改进设计提供参考。研究表明,由温升引起的热应力对制动器的应力场占主导作用,且高应力区主要集中在摩擦区域。
[Abstract]:As an important part of the large vertical axis wind turbine, the transmission and braking systems play an important role in the operation and safety of the whole wind turbine. At present, the large power vertical axis wind turbines have little share in the market, and there is no fixed design system for the transmission system of the high-power vertical axis wind turbines. In order to solve this problem, the transmission system and braking system of megawatt vertical axis wind turbines are studied in this paper. In order to solve the difficulties of the transmission system of MW vertical axis wind turbines, a variety of wind turbine transmission schemes are compared. An optimal drive structure scheme is established: the whole machine is a semi straight drive drive, and the speed increase device and generator are installed near the ground; the bearing scheme is supported by three stages bearing, the main bearing (grade I bearing) is a rotating disk bearing, the guide bearing (second grade bearing) is a roller bearing and the lower guide bearing (grade III bearing) is a thrust roller. The bearing, the upper guide bearing and the lower guide bearing all adopt split bearing. In order to obtain the load of the wind turbine under different working conditions, the aerodynamic characteristics of the wind wheel are calculated by the Fluent numerical simulation method, and the structure size of the shaft of the drive shaft is determined according to the load, so that the axial structure meets the design requirements and carries out the strength. Check, fatigue analysis and modal analysis. In order to solve the problem of high power wind turbine braking reliability, the brake system model is established, and the force analysis is carried out on the brake installed in different positions. According to the different braking conditions, the braking torque and the braking time are calculated for the scheme of the mechanical brake system, and the high speed is determined. The temperature field and stress field of the brake friction pair are analyzed with the two stage braking scheme of shaft + low speed shaft, and the ANSYS software is used to analyze the temperature field and stress field of the brake friction pair. The results show that the temperature distribution of the brake disc is not uniform, the high temperature area is mainly concentrated on the friction contact surface. The temperature of the brake lining is much higher than the brake disc, and the surface temperature distribution is more uniform. The temperature distribution of the brake disc and the brake lining is similar in the two working conditions, and the emergency temperature is relatively high. The mechanical stress analysis and thermal stress analysis. Through the stress field analysis, it can be used to determine whether the brake disc will produce hot cracks or failure, and provide reference for the improved design of the brake disc. The research shows that the thermal stress caused by the temperature rise is dominant to the stress field of the brake, and the high stress zone is mainly concentrated in the friction area.
【学位授予单位】：哈尔滨工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TM315

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