超细分级机进料管内颗粒浓度分布特性的数值模拟

Numerical Simulation on Concentration Distribution of Particles in the Feeding Pipe of a Superfine Classifier

采用RNG k-ε湍流模型和随机轨道模型,对SCX超细分级机进料管内颗粒浓度分布进行了数值模拟,探讨了入口固体浓度、入口气速、粒径等的影响.结果表明,弯管出口附近颗粒浓度分布波动大,但在距弯管出口距离为6倍管径处波动趋于稳定.整个竖直段任意横截面可分为高浓度和低浓度区域,且两区的无因次半径(r/R)有一定范围:X方向低浓度区为-1<r/R<0.75,高浓度区为0.75<r/R<1;Y方向低浓度区为-0.75<r/R<0.75,高浓度区为-1<r/R<-0.75和0.75<r/R<1;两区的范围不随入口固体浓度、入口气速和轴向高度改变而变化.随入口气速增加,竖直段局部颗粒浓度减小,靠近壁面的区域减小更为明显,而入口固体浓度的改变对无因次颗粒浓度分布影响较小.

RNG k-e turbulent model and the stochastic track model were respectively adopted to simulate the particle concentration distribution characteristics in the feeding pipe of a superfine classifier SCX.The effects of inlet solid concentration,inlet velocity and particle diameter on the concentration distribution of particles were analyzed.The results show that the distribution fluctuates significantly near the bending outlet,but it becomes more stable from the bending outlet of 6 times pipe diameter.The particle concentration in the vertical section can be divided into high and low concentration areas.The dimensionless radius （r/R） of two areas is in a certain range.In the X direction,the low concentration range is-1r/R0.75,and the high one 0.75r/R1.In the Y direction,the low concentration range is-0.75r/R0.75,and the high one-1r/R-0.75 and 0.75r/R1.Meanwhile,the size of two areas is basically unchanged with the change of the inlet solid concentration,inlet air velocity and axial height.In the vertical section,the local particle concentration decreases with the increase of the inlet velocity,and the particle concentration near the wall decreases much more obviously.The change of the inlet solid concentration has less influence on the dimensionless concentration distribution of particles.