基于CFX的水平管等径三通失效分析数值模拟

Numerical Simulation of Failure Analysis of Straight Tee of Horizontal Pipe Based on CFX

应用计算流体动力学(CFD)方法及CFX软件,建立水平管等径三通中的流体湍流和冲蚀数学模型。考虑等径三通近壁面处湍流的衰减,设定流动介质的气相为连续相,液相为离散相,边界条件设定为质量入口和压力出口组合,其中进口为气液两相质量流量和体积分数,出口为截面平均静压。采用稳态模拟和有限体积法对充分发展的气液两相流管内流动进行数值模拟,经过计算得到流动介质的速度流线、速度矢量及气液分布。其中,气相速度最大为21.2 m/s,液相速度最大为13.4 m/s;流速增大时,气液两相流的壁面切应力相应增大,气相最大切应力为36.87 Pa,液相最大切应力为68.24 Pa。剪切力破坏管壁腐蚀产物膜,加剧腐蚀产物膜的脱落。综合各因素解释等径三通冲蚀磨损的原因,同时结合失效样品壁厚检测结果,论证气液两相流对水平管等径三通冲蚀磨损的失效规律。

The mathematical model of fluid turbulent flow and erosion in straight tee of horizontal pipe was established by application of CFD method and CFX softwares. Considering attenuation of near - wall turbulence of equal tee and setting the flow medium as gas continuous phase and liquid phase as discrete phase, boundary conditions are set as the combination of mass inlet and pressure outlet. The inlet conditions are the mass flow rate and volume fraction of the gas - liquid two - phase flow, and the outlet condition is sectional average static pressure. The steady state simulation and finite volume method are applied for the numerical simulation for the full development of the two phase flow of gas and liquid inside the pipe to get the flow lines, velocity vector and distributions of gas and liquid. The maximum gas - phase velocity is 21.2 m/s, and the maximum liquid - phase velocity is 13.4 m/s. When the flow velocity is increased, the wall shear stress of the gas -liquid two -phase is increased accordingly. The maximum shear stress of the gas phase is 36.87 Pa and the maximum shear stress of liquid phase is 68.24Pa. The share stress damages the corrosion product films on the wall and accelerates the falling of the corrosion product films. The erosion - wear law of gas - liquid two - phase in a straight tee of a horizontal pipe is testified by analysis of erosion and testing results of wall thickness of failed pipe.