浮力块对隔水管固有频率的影响研究

Effect of Buoyancy Modules on Riser Natural Frequency

为了避免钻井隔水管在深海环境中出现涡激振动现象,利用ANSYS软件,针对带浮力块和不带浮力块的隔水管系统进行了模态分析。定量研究了浮力块密度、长度及不同布置位置对隔水管固有频率的影响。研究结果表明,布置浮力块后隔水管的各阶固有频率都会相应增大;当隔水管布置浮力块的长度与起始位置相同时,随着浮力块密度的增大,隔水管的各阶固有频率值相应减小;当布置浮力块的密度与长度相同,且布置浮力块的位置靠近隔水管的下端时,隔水管的各阶固有频率越小;当布置浮力块的密度与起始布置位置相同时,隔水管的各阶固有频率会随着布置浮力块长度的增大而增大。得到的结论对涡激响应的研究具有重大意义。

To avoid vortex-induced vibration of marine drilling riser in the deep water environment, modal anal- ysis has been conducted on the riser system with and without buoyancy modules by using ANSYS software. The effects of buoyancy module density, length and layout positions on the natural frequency of the riser have been quantitatively studied. The results show that the riser natural frequency will increase after deployment of buoyancy modules. Given the same buoyancy module length and layout position, natural frequency of each order of riser will decrease with the increase of buoyancy density. Given the same buoyancy module length and density, natural frequency of each order of riser will decrease with the buoyancy modules closer to the downward of riser. While given the same buoyancy module density and layout position, natural frequency of each order of riser will increase with the increase of buoyancy mod- ules length. The conclusion could provide great significance for the study of vortex-induced responses.