柔性压力管道甩击特性数值模拟

Numerical simulation of the flicking characteristics of flexible pressure pipes

柔性压力管道作为一种重要的流体输送工具,以适用性强、安装快捷等特点广泛应用于临时或机动工程中,但随其耐压等级与额定流量不断提高,管道的振甩现象愈发突出,甩击事故时有发生,存在重大安全隐患。利用ANSYS Workbench平台对柔性压力管道脱扣断裂甩击行为进行数值模拟,研究了管道流速、流体物性参数、管道弯曲长度和弯曲半径、约束位置对甩击运动的影响。结果表明:管道的甩击运动具有很强的非线性特征,脱扣端的变形位移和甩击速度最大,固定端的等效应力最大;随管内流速增加,管道甩击的变形位移、甩击速度、等效应力增加,应变能呈高次方变化;随流体密度增加,管道甩击运动的主要参数都线性增加,流体黏度增加,管道甩击更加剧烈;管道长度越长,其运动周期越长;弯曲半径增大,管道甩击运动的主要参数都减小;而管道安全扣的约束位置主要影响了管道运行的长度和弯曲半径,从而对甩击运动产生影响,管道甩击振动由二阶模态主导。

As an important fluid transportation equipment, flexible pressure pipeline is widely used in temporary or mobile engineering due to its applicability. However, as its pressure level and flow rate continue to increase, the vibration of the pipeline becomes more and more prominent, and slamming accidents often occur. In this paper, the ANSYS Workbench platform was used to numerically simulate the flicking behavior of flexible pressure pipeline tripping. Based on this, the effects of pipeline flow rate, fluid physical parameters, pipe bending length and bending radius, and restraint position on the flicking motion were studied. The results show that the slamming motion of the pipeline has strong nonlinear characteristics, the deformation displacement and slamming speed at the tripping end are the largest, and the equivalent stress at the fixed end is the largest. With the increase of the flow velocity, the deformation displacement, the slamming speed and the equivalent stress of the pipe slamming increase, and the strain energy changes at a high power. With the increase of fluid density, the main parameters of the pipeline slamming movement increase linearly and the viscosity of the fluid increases, resulting in more intense slamming of the pipeline. The longer the pipeline length, the longer the motion cycle. With the increase of the bending radius, the main parameters of the pipeline slamming movement are reduced. The constrained position of the pipeline safety buckle mainly affects the length of the pipeline and the bending radius, thus affecting the slamming movement. The shock vibration of pipeline is dominated by the second order mode.