冰水两相流管道冲蚀磨损影响与防护

Erosion Influence and Protection of Ice-Water Two Phase Flow Pipe

目的研究低温条件下冰晶颗粒随水流进入弯管并对弯管造成的冲蚀磨损,确定弯管关键防护区域。方法通过欧拉-拉格朗日双向耦合法,研究了冰晶颗粒的斯托克斯数、流速、粒径、质量流率以及管道弯径比对磨损特性的影响。结果冰晶颗粒的斯托克斯数会显著影响最大磨损率区域变化,当斯托克斯数由2.8增大至5.84时,最大磨损率区域由弯头内侧拱壁向弯头外拱壁与出口管道连接处转移,斯托克斯数高出或低于该范围时,最大磨损率位置不再发生变化,斯托克斯数的增加在一定范围内对最大磨损率没有绝对性影响。流速、粒径和质量流率的增大会使得最大磨损率不断升高,粒径和流速的变化会改变最大冲蚀磨损区域,而质量流率的改变对最大冲蚀磨损区域没有明显影响。弯径比的增大也会使得最大冲蚀磨损区域由弯头内拱壁向外拱壁与直管连接处转移,并降低最大磨损率。结论冰水两相流弯管的最大冲蚀磨损区域主要集中在弯头内拱壁、弯头外拱壁与出口直管连接处、靠近弯头侧壁三处,且大弯径比的管道可实现减磨防护。

The work aims to study erosion of pipe by ice particles in water flow at low temperature and confirm critical protection regions of the elbow.The effects of Stokes numbers,velocity,particle diameter,mass flow rate and R/D ratio on erosion characteristics were studied through two-way coupling method of euler and lagrange.The Stokes number of ice particles had a significant effect on the regions with the maximum erosion rate.When the Stokes number increased from 2.8 to 5.84,the location with the maximum erosion rate region was transferred from inner extrados of the bend to outer extrados of the bend close to straight pipe.When the Stokes number was higher or lower than that range,the location with the maximum erosion regions did not change at all.The increase of Stokes number had no obvious effect on the maximum erosion rate within a certain range.As the velocity,particle diameter and mass flow rate increased,the maximum erosion rate grew.The variations of particle diameter and velocity changed the location of with the maximum erosion rate regions,but the mass flow rate had no obvious effect on the location of maximum erosion rate regions.The growth of R/D ratio also caused the location with the maximum erosion rate to shift from inner extrados to outer extrados of the bend,where it was close to straight pipe and the maximum erosion rate decreased.The regions with the maximum erosion rate of ice-water two phase flow elbow are mainly concentrated at three zones:inner extrados of the bend,outer extrados of the bend close to straight pipe and the side wall near the elbow.Furthermore,erosion rate can be reduced by a long R/D ratio elbow.