充填料浆颗粒轨迹特征及管壁磨损机理

Particle trajectory characteristics of filling slurry and pipe wall wear mechanism

为揭示充填管道90°弯头的冲蚀磨损机理,基于流变学、流体力学和材料力学,通过室内流变实验与数值模拟相结合,探究充填料浆的流变参数和管道的磨损特征,对不同运动状态下颗粒对管道的冲蚀磨损机理进行分析.结果表明,充填料浆的塑性黏度系数为0.231,剪切速率与剪切应力呈线性关系,符合Bingham模型.由料浆颗粒的受力分析结果可知,颗粒在弯管内处于推移和悬移两种运动状态,弯管发生冲蚀磨损与料浆颗粒的流动形式及运动状态有关,推移运动对管道造成的磨损最严重.数值模拟结果表明,管道转弯角度60°~85°的区域为冲蚀磨损较严重的区域,管道下侧壁面的磨损率远大于上侧壁面;弯管冲蚀的磨损速率随料浆流速的增大而增大,当流速为7 m/s时,磨损速率最大;随着管径增大,弯管处的压力差减小,磨损速率降低;磨损速率与管道的曲率半径呈负相关关系,曲率半径越大,料浆的速度场分布越均匀.

In order to explore the erosion wear mechanism of the 90° bend of a filling pipeline and reveal the influence of main factors on pipeline wear,fluid mechanics,material mechanics and other theories,the rheological parameters of filling slurry and the wear characteristics of pipeline were obtained based on rheology and by combining laboratory rheological experiment with numerical simulation.The erosion and wear mechanism of particles on the pipeline under different motion state was analyzed,and the rheological experiment results showed that the plastic viscosity coefficient of the slurry was 0.231 and its shear rate had a linear relationship with the shear stress,which conformed to the Bingham model.According to the force analysis results of slurry particles,the erosion wear of bent pipe was related to the flow form and motion state of slurry particles in the pipeline,with the main reason being the slip and transition movement of particles.The numerical simulation results showed that the area of turning angle 60°~85°was a serious area of erosion wear,and the wear rate of the lower side wall was much higher than that of the upper side wall.The erosion wear rate increased with the increase of the slurry flow rate.When the flow rate was 7 m/s,the wear rate was maximum.With the increase of the pipe diameter,the pressure difference at the bend decreased and the wear rate decreased.The wear rate was negatively correlated with the curvature radius of the pipe.The larger the curvature radius,the more uniform the distribution of slurry velocity field.