气液固多相流对法兰接缝处的腐蚀行为研究

目的揭示不同条件下法兰接缝处的腐蚀速率。方法基于流动动力学数值模拟软件,分析法兰接缝处的流场变化、不同因素的电化学腐蚀速率和冲刷腐蚀速率。结果在文中的研究条件下,随着接缝深度的增加,法兰接缝处的流速分布分为0～0.6 mm和0.6～5 mm两个阶段,在法兰接缝表面均存在明显的压力梯度层和温度梯度层。同时随着固体杂质质量流量的增大,法兰处腐蚀速率呈直线增大,当其质量流量大于4kg/s时,其腐蚀速率达到最大值;而含砂流体流速与腐蚀速率基本符合正态分布规律。结论对于气液固多相流条件下法兰处的腐蚀,主要是由于电化学腐蚀和冲刷腐蚀相互作用产生的,并且其冲刷腐蚀速率远远大于电化学腐蚀速率。

Corrosion Behavior of Gas-Liquid-Solid Multiphase Flow on Flange Joints

Objective To explore the corrosion rate in crevice of flange joints. Methods Based on CFD numerical simulation software, this paper studied the corrosion rate of flange joints, including the flow field, electrochemical and erosion corrosion rate. Results The velocity distribution at the flange joint in the above study conditions can be divided into two stages of 0-0.6 mm and 0.6-5 mm in the direction of joint depth, and there were obvious pressure gradient layer and temperature gradient layer on the surface of the flange joint. Meanwhile, with the increase of the mass flow rate of solid impurities, the corrosion rate at the flange increased linearly; and when the mass flow rate was greater than 4 kg/s, the corrosion rate reached the maximum. The velocity of sand-containing fluid and corrosion rate are normally distributed. Conclusion Therefore, the corrosion of flange joints under the gas-liquid-solid multiphase flow condition is mainly caused by the interaction of electrochemical corrosion and erosion corrosion, and its erosion corrosion rate is much higher than the electrochemical corrosion rate.