流线型孔板流量计液固两相流冲蚀磨损数值模拟

目的探究在管输液固两相流体时,固体颗粒对孔板流量计造成的冲蚀磨损。方法运用基于欧拉-拉格朗日算法的DPM模型,对液固两相流体计量工艺中孔板流量计的冲蚀问题进行数值仿真,预测孔板流量计在液固两相流体流量计量工艺中易发生冲蚀磨损的区域。探究入口液相速度、固体颗粒粒径以及等数量颗粒冲击壁面时,固体颗粒粒径对孔板最大冲蚀速率的影响,并对比管输液固两相流体时,固体颗粒粒径对不同形状的孔板造成的冲蚀磨损速率大小。结果在孔板流量计的突缩管段易产生严重的液固冲蚀失效,最大冲蚀速率随着液相入口速度的增大而增加。当固体颗粒的质量流量相等时,最大冲蚀速率随着颗粒粒径的增加而减小;当单位时间内流经孔板的固体颗粒数量相等时,冲蚀磨损速率随着固体颗粒粒径的增加而增大。在液固两相流管道体系中,固体颗粒对凸型孔板造成的冲蚀磨损行为最弱。结论大颗粒对孔板的冲蚀磨损比较严重,在孔板计量过程中应严格注意。在流体中存在大量大颗粒时,采用凸型孔板流量计能有效改善冲蚀磨损情况。

Numerical Simulation of Liquid/Solid Erosive Wear of Streamlined Orifice Plate Flowmeter

The work aims to analyze erosive wear caused by solid particles on orifice plate flowmeter during transmission of liquid/solid fluid. DPM model based on Euler-Lagrangian algorithm was used to numerically simulate erosion of the liquid/solid orifice plate flowmeter in liquid/solid fluid metering process. Areas in which the orifice plate flowmeter was prone to erosive wear in liquid/solid fluid metering process were predicted. The effects of inlet liquid velocity and solid particle size (when equal number of particles struck the wall surface) on difform orifice plate were explored. Erosive wear rate on the difform orifice plate during transmission of liquid/solid fluid was compared. Severe liquid/solid erosion failure might appear in such pipe sections subject to sudden contraction on the flowmeter. The maximum erosion rate increased with the increase of inlet liquid velocity. When mass flow rate of solid particles was equal, the maximum erosion rate decreased with the increase of particle size. When an equal number of solid particles of different particle size flowed through the orifice plate in unit time, erosion wear rate increased with the increase of solid particle size. For liquid/solid fluid flow metering process, the solid particles caused less erosive wear on convex orifice plate. Large particles will cause serious erosive wear on the orifice plate, hence it should be strictly noted in the orifice plate metering process. In case of plenty of large particles in the fluid, use of convex orifice plate flowmeter can effectively improve erosive wear.