海底管道悬跨段在内输段塞流和外部海流共同作用下的动力行为研究

项目名称： 海底管道悬跨段在内输段塞流和外部海流共同作用下的动力行为研究

项目编号： No.51509258

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 其他

项目作者： 安晨

作者单位： 中国石油大学（北京）

项目金额： 24万元

中文摘要： 油气输运海底管道中气液两相段塞流引起的压力波动会使管道悬跨段产生振动，而振动过大将导致管道关键部件因疲劳或微动磨损发生破坏。内输段塞流海底管道在外流引起的涡激振动作用下会产生更严重的疲劳损伤。避免管道失效的理论基础是对内输段塞流海洋管道振动特性的深刻理解，但目前对该问题的研究报道很少。因此，开展海底管道悬跨段在内输段塞流和外部海流共同作用下动力行为研究尤为重要。本项目通过理论分析、数值模拟及实验手段研究海底管道悬跨段在内输段塞流和外部海流共同作用下的非线性振动特性，揭示内输段塞流的统计特性对海洋管道动力学特性的影响，阐明气液各相流动参数及管道结构参数对海洋管道振动特性的作用。研究目标在于澄清内输气液两相段塞流对海底管道振动的激励机理，建立内输段塞流海底管道的失效判据，形成海底管道悬跨段在内输段塞流和外部海流共同作用下振动特性的系统研究方法，为深水管道设计及振动控制提供必要的理论支持。

中文关键词： 海底管道；悬跨；段塞流；动力分析；积分变换

英文摘要： Gas-liquid two-phase slug flow can generate dynamic fluid forces which may induce structural vibration of subsea pipelines conveying oil and gas production fluids. Excessive vibration may cause component failures due to fatigue and fretting-wear. This phenomenon may generate more severe damage when considering the vortex-induced vibration of subsea pipeline free span subjected to external marine current. Such detrimental vibration can be avoided by comprehensive dynamic analysis of subsea pipeline free span, preferably at the design stage. This requires a fully understanding of vibration excitation mechanisms of subsea pipeline free span subjected to simultaneous internal slug flow and external marine current, however, the literature focused on this aspect is quite limited. Therefore, to perform a systematic study of vibration behavior of subsea pipeline free span subjected to such loadings, constructing the dynamic model for subsea pipeline free span conveying gas-liquid slug flow, is essential to form the theoretical framework. The proposed work will make an overview of the existing two-phase slug flow models, creating the governing equations for vibration behavior of horizontal tube subjected to internal two-phase slug flow and external current. Theoretical analysis, numerical simulation and experimental approach are utilized to investigate the dynamic characteristics of subsea pipeline free span subjected to internal two-phase slug flow and external current, where the theoretical analysis is mainly based on the generalized integral transform technique (GITT), the numerical simulation is based on the commercial code for fluid-structure interaction (FSI) problems ANSYS-CFX and ANSYS-Mechanical, and the experimental approach is based on a pulse-echo ultrasonic technique with a single fast transducer and a visualization technique with a high-speed digital camera for measuring the hydrodynamic parameters of slug flow. The effect of the statistical characterization of gas-liquid slug flow on the dynamic behavior of free span is analyzed. The effect of volumetric flux of gas and liquid phase, physical parameters, hydrodynamic parameters, slug frequency, external current speed, initial drapability of free-span, material parameters and boundary conditions on the dynamic characteristics of subsea pipeline free span (including natural frequency, mode shape, maximum amplitude, stability, resonance, bifurcation and chaos). The aim of this project is to reveal the excitation mechanism of subsea pipeline free span by internal gas-liquid slug flow, to create the failure criteria for free span vibration subjected to simultaneous internal slug flow and external marine current, and to form the systematic investigation methods for such FSI problem, which is supply the indispensible theoretical support for the pipeline vibration control and design.

英文关键词： Subsea pipeline;Free span;Slug flow;Dynamic analysis;Integral transform