A numerical study on the erosion of particle clusters in an abrupt pipe was conducted by means of the combined computational fluid dynamics (CFD) and discrete element methods (DEM). Furthermore, a particle-wall extrusion model and a criterion for judging particle collision interference were developed to classify and calculate the erosion rate caused by different interparticle collision mechanisms in a cluster. Meanwhile, a full-scale pipe flow experiment was conducted to confirm the effect of a particle cluster on the erosion rate and to verify the calculated results. The reducing wall was made of super 13Cr stainless steel materials and the round ceramsite as an impact particle was 0.65 mm in diameter and 1850 kg/m3 in density. The results included an erosion depth, particle-wall contact parameters, and a velocity decay rate of colliding particles along the radial direction at the target surface. Subsequently, the effect of interparticle collision mechanisms on particle cluster erosion was discussed. The calculated results demonstrate that collision interference between particles during one cluster impact was more likely to appear on the surface with large particle impact angles. This collision process between the rebounded particles and the following particles not only consumed the kinetic energy but also changed the impact angle of the following particles.
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机译:利用计算流体力学(CFD)和离散元方法(DEM)相结合的方法对突变管中颗粒团簇的侵蚀进行了数值研究。此外,建立了颗粒壁挤压模型和判断颗粒碰撞干扰的判据,以分类和计算由不同颗粒间碰撞机理引起的腐蚀速率。同时,进行了全面的管道流动实验,以确认颗粒团簇对侵蚀速率的影响并验证计算结果。还原壁由超级13Cr不锈钢材料制成,作为冲击粒子的圆形陶粒直径为0.65 mm,密度为1850 kg / m 3 sup>。结果包括腐蚀深度,粒子与壁的接触参数以及在目标表面沿径向碰撞粒子的速度衰减率。随后,讨论了粒子间碰撞机理对粒子团簇腐蚀的影响。计算结果表明,在一个团簇撞击过程中,粒子之间的碰撞干扰更可能出现在具有较大粒子撞击角的表面上。反弹的颗粒与随后的颗粒之间的碰撞过程不仅消耗了动能,而且改变了随后的颗粒的冲击角。
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