共查询到20条相似文献,搜索用时 140 毫秒
1.
2.
3.
4.
5.
针对传统变桨轴承方法中的刚性假设不能反应变桨轴承动态运行特点的问题,引入了在线测试与仿真分析技术,对变桨轴承动态柔性特性进行了研究。分析了变桨轴承运行的受载特点,提出了一种基于应变载荷测试与位移传感器的在线测试方法,以测试风电机组不同功率下变桨轴承内外圈轴向位移、径向位移和载荷;建立了考虑周边结构与变桨轴承柔性的变桨系统有限元模型,并以在线测试所得载荷作为有限元分析输入载荷,进行了仿真分析;最终对不同功率下的变桨轴承轴向位移、径向位移测试数据与仿真数据进行了对比分析。研究结果表明:变桨轴承载荷、变桨轴承内外圈轴向位移、径向位移随风轮转动呈现周期性交替变化规律,不同位置变化规律特点不同,体现了变桨轴承的动态柔性特性;该特性可应用于变桨轴承可靠性的研究。 相似文献
6.
7.
8.
9.
针对风力发电机变桨柜焊缝开裂问题,对变桨柜进行结构优化和强度评估,并进行现场应力测试验证。首先采用Simpack软件对变桨柜总装结构进行动力学建模和仿真分析,确定变桨柜应力幅值变化最大的危险位置对其进行有限元分析;接着采用有限元分析软件ANSYS及疲劳分析软件Fe-safe对变桨柜进行焊缝极限强度与疲劳强度评估;最后采用应变应力测试装置对风场运行的变桨柜进行焊缝动态应力测试。结果表明,优化后的变桨柜焊缝极限与疲劳强度安全系数均大于1,满足GL规范强度设计要求;风场测量的焊缝最大应力幅值与有限元分析计算的应力幅值相比最小误差为6.8%,验证了有限元分析方法的准确性,为有效解决风力发电机变桨柜焊缝开裂问题提供了参考方法。 相似文献
10.
11.
12.
为了改善和提高电梯的气动特性和运行稳定性,基于SST k-ω湍流模型对电梯进行空气流体仿真,计算气动阻力、侧翻力矩、俯仰力矩,分析实验数据变化趋势。通过最小二乘拟合,建立电梯气动特性的一元数值模型。根据正交实验结果与一元数值模型,基于MATLAB回归分析,建立电梯气动特性的多元数值模型,并以此作为目标函数,以气动阻力、侧翻力矩和俯仰力矩最小作为优化目标,基于遗传算法进行电梯气动特性的多目标优化,仿真验证优化后电梯气动特性得到较大改善,为电梯气动特性的改善提供了一定的参考价值和意义。 相似文献
13.
14.
针对风机叶片疲劳加载过程振动特性,建立旋转偏心块驱动的叶片疲劳加载系统动力学模型。基于拉格朗日方程推导出系统的数学模型,利用平均法近似解析系统动力学方程,得出振动过程中电机转矩平衡方程。分析振动频率的变化规律,建立仿真模型,对系统频率捕获过程进行数值仿真,揭示系统的自同步振动特性。风机叶片疲劳加载试验表明:叶片在受迫振动时,叶片振动频率并不总等于驱动频率;驱动频率与叶片固有频率偏差较大时,叶片振动幅值及频率波动明显;频率偏差在较小区间范围(0.47~0.62Hz)时,偏心块驱动系统与叶片容易发生频率捕获,振幅较小并趋于稳定;在负载转矩较大而电机功率不足时,偏心块会发生转速跳变。 相似文献
15.
NUMERICAL SIMULATION ANALYSIS OF EXTERNAL FLOW FIELD OF WAGON-SHAPED CAR AT THE MOMENT OF PASSING 总被引:1,自引:0,他引:1
GU Zhengqi HE Yibin ZHOU Wei JIANG Bo 《机械工程学报(英文版)》2008,21(4):76-80
In the course of studying on aerodynamic change and its effect on steering stability and controllability of an automobile in passing, because of multi interaction streams, it is difficult to use traditional methods, such as wind tunnel test and road test. If the passing process of an automobile is divided into many time segments, so as to avoid the use of moving mesh which takes large calculation resource and CPU processing time in calculating, the segments are simulated with computational fluid dynamics (CFD) method, then the approximate computational results about external flow field will be obtained. On the basis of the idea, the change of external flow field of wagon-shaped car at the moment of passing is simulated through solving three-dimensional, steady and uncompressible N-S equations with finite volume method. Numerical simulation analysis of side force coefficient, stream lines, body surface pressure distribution of wagon-shaped car are presented and a preliminary discussion of aerodynamic characteristics of correlative situations is obtained. Finally, the C3 -x/l curve of side force coefficient(C3) of car following relative distance (x/l) between cars is obtained. By comparison, the curve is coincident well with the experimental data, which shows creditability of numerical simulation methods presented. 相似文献
16.
海参捕捞机器人在水下捕捞作业时的性能受姿态变化的影响较大,为了使海参捕捞机器人始终保持最佳性能,需要在实际应用前对不同姿态下的捕捞机器人进行水动力学分析。利用计算流体力学软件 中的RNG 湍流模型作为仿真模型,考虑到仿真计算的精度,对近壁区域的处理进行了研究,在湍流模型的基础上加入了标准壁面函数。应用该模型对水下捕捞机器人水平直航、水平斜航和垂直斜航3种姿态下的水阻力和水阻力矩进行分析。结果表明:不同的姿态将影响水下捕捞机器人所受到的水阻力和水阻力矩的大小;在水平直航时捕捞机器人受到垂直向下的作用力较大,而产生的俯仰力矩较小;在水平斜航时漂角对捕捞机器人的影响较大;在垂直斜航时捕捞机器人的垂向力和俯仰力矩均随着流速和攻角的增大而增加。 相似文献
17.
风力机模拟系统使在实验室内开展风力发电技术的各项研究成为可能。分析了风力机特性,建立了风力机模型。通过对异步电机间接磁场定向矢量控制技术的研究,考虑到安装速度传感器具有诸多缺陷,提出基于模型参考自适应(MRAS)转速辨识理论的无速度传感器异步电机的风力机模拟控制方法,并且考虑到转子时间常数对矢量控制系统的影响,采用同时辨识电机转速和转子时间常数,使系统辨识转速同时,对电机参数变化具有较强的鲁棒性。利用MATLAB/SIMULINK搭建了基于无速度传感器异步电机的风力机模拟系统,通过对风力机特性,最大风能捕获和电机参数对矢量控制系统影响的仿真,证明了系统的可行性。 相似文献
18.
19.
20.
Aiming at the Megawatt (MW) scale wind turbine, a dynamic analysis and simulation method is presented to research blade loads and dynamic characteristics. To consider blade flexible deformation, the whole blade was divided into a number of units. Each unit was treated as a rigid body, the flexible connection between two adjacent units is considered. A nacelle coordinate system, a rotating shaft coordinate system, and a blade coordinate system were employed to describe the wind turbine blade. In those coordinate systems, blade inertial load calculation model, centrifugal force load calculation model and gravity load calculation model are established. Combining load model with the whole model of wind turbines, the real-time dynamic simulation model of blade loads was established in Simulink circumstance and a numerical simulation was performed. Based on the simulation analysis, some research results were obtained. When the large instantaneous fluctuation of electromagnetic torque of generator happens, rotor speed does not appear to have large fluctuation due to the inertia of the wind rotor, but the blade vibration speed changes obviously. Gravity has a periodic variation in the process of blade rotation and has a large influence on the edgewise moment. The research results provide a helpful reference for the structure design, operation, and control of wind turbines. 相似文献