减振装置对导管架涡激振动影响的数值仿真

发布时间：2018-10-23 09:13

【摘要】：目前世界能源形势日趋严峻，深海油气资源的开发受到了石油界广泛的关注。随着海洋油气勘探开发的深水化发展，导管架平台由十几米水深发展到五百米水深，杆件的长度大大增加。在导管架的建造过程中，当一定速度的风流经杆件时会发生风致涡激振动现象，频繁的风致振动将会导致导管架杆件疲劳破坏出现裂纹，降低制造质量和精度，极大地影响到了导管架结构的安全生产和使用寿命。因此，研究导管架杆件涡激振动控制方法及其实用的装置具有重要的理论与实际应用价值。本文首先阐述了圆柱绕流和涡激振动的机理，分析影响导管架平台杆件涡激振动的因素。采用Navier-Stokes方程作为不可压缩粘性流体的控制方程，在低雷诺数下建立了导管架杆件绕流问题的三维数值模型，，对未安装减振装置的导管架绕流流场进行了模拟，将计算得出的升力系数、阻力系数、涡旋脱落频率和斯托哈尔数与文献结果对比，验证模型的有效性，并为后面评定减振装置的效果奠定了基础。然后对安装减振装置的导管架流场在同一雷诺数下进行了数值模拟，与未安装减振装置的导管架流场的计算结果进行对比分析。观察安装减振装置前后导管架绕流流场的速度场、压力场、流线及涡量场等流动特性的变化，计算其减振、减阻效果并分析其机理，重点研究了减振装置对导管架受力情况和流场三维方向产生的影响。改变减振装置的位置，数量及排列方式，比较安装不同数量及位置的减振装置对导管架涡激振动的控制效应，通过综合考虑给出最佳安装方案，为指导实际工程提出依据。
[Abstract]:At present, the world energy situation is becoming more and more serious, and the exploitation of deep-sea oil and gas resources has been widely concerned by the petroleum industry. With the development of deepwater exploration and development of offshore oil and gas, the jacket platform has been developed from a depth of more than ten meters to a depth of 500 meters, and the length of the rod has been greatly increased. During the construction of the jacket, the wind-induced vortex-induced vibration will occur when the wind flow of a certain speed passes through the bar. Frequent wind-induced vibration will lead to the fatigue failure of the jacket bar and reduce the manufacturing quality and precision. It greatly affects the safety production and service life of jacket structure. Therefore, it has important theoretical and practical application value to study the control method of vortex vibration of jacket bar and its practical device. In this paper, the mechanism of the flow around a cylinder and the vortex-induced vibration is described, and the factors affecting the vortex-induced vibration of the jacket platform are analyzed. Using the Navier-Stokes equation as the governing equation of incompressible viscous fluid, a three-dimensional numerical model of the flow around the jacket rod is established at low Reynolds number. The flow field around the jacket without vibration absorber is simulated. The calculated lift coefficient, drag coefficient, vortex shedding frequency and Stohar number are compared with the results of literature to verify the validity of the model and lay a foundation for evaluating the effect of vibration absorber. Then numerical simulation of the jacket flow field with the same Reynolds number is carried out, and the results are compared with the results of the jacket flow field without the vibration absorber. The changes of velocity field, pressure field, streamline and vorticity field around the jacket before and after the installation of vibration absorber are observed, the effect of damping and drag reduction are calculated and the mechanism is analyzed. The influence of vibration absorber on the stress of jacket and the three-dimensional direction of flow field is studied. By changing the position, quantity and arrangement of the vibration absorber, comparing the control effect of the vibration absorber with different number and position on the vortex vibration of the jacket, the optimal installation scheme is given through comprehensive consideration, and the basis for guiding the practical project is put forward.
【学位授予单位】：天津大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：P751

【相似文献】