储气库注采井气液两相冲蚀模型及结果仿真

Gas-Liquid Two-Phase Erosion Model and Result Simulation of Injection-Production Well in Gas Storage

针对储气库注采井管柱的气液两相流冲蚀环境建立两相流冲刷腐蚀仿真模型。其中以气相为连续相,液相为离散相,加入液相与壁面的碰撞过程以及蒸汽在壁面的析出过程,得到管柱内两相流流体状态分布;基于液滴与壁面的碰撞过程,建立流体介质对管柱的冲刷磨损模型;将电化学腐蚀模型与冲刷磨损模型进行耦合计算,得到电化学腐蚀—冲刷磨损耦合作用模型。基于此耦合模型开展管壁冲刷腐蚀仿真分析,得到温度梯度、压力梯度、流速梯度对冲蚀速率的影响关系。结果表明:温度、压力、流速均会导致管材冲蚀速率的增加,其中温度较低时管材的冲蚀速率增加较快,之后冲蚀速率增加较慢;冲蚀速率随着压力的增加基本呈线性增加的关系;冲蚀速率随着流速的增加先缓慢增加,流速达到10 m/s左右后快速增加,临界冲蚀流速在12~15 m/s之间。

In this paper,a two-phase flow erosion simulation model was established for the gas-liquid two-phase flow erosion environment of the pipe string of injection-production well in gas storage.Taking the gas phase as a continuous phase and the liquid phase as a discrete phase,the distribution state of the two-phase flow fluid was obtained by adding the precipitation process of the steam on the pipe wall surface and the collision process between the liquid phase and the pipe wall surface.A model simulating the erosion of the pipe string caused by the fluid medium was established based on the collision process between the liquid drop and the pipe wall surface.Through a coupling calculation of the electrochemical corrosion model and the erosion model,an electrochemical corrosion-erosion model was obtained.Based on this coupled model,the simulation analysis of pipe wall erosion and corrosion was carried out,and the influences of temperature,pressure and flow velocity gradient on erosion rate were obtained.Results showed that the erosion rate of pipe would increase with the rising of temperature,pressure and flow rate.The erosion rate of the pipe increased faster when the temperature was lower,and it increased relatively slowly when the temperature was higher.Furthermore,the erosion rate basically increased linearly with the increase of pressure.The erosion rate increased slowly with the increase of the flow velocity firstly,and when the velocity reached 10 m/s,it started to increase rapidly.The critical velocity was between 12 m/s and 15 m/s.