通风管路90°弯管壁面颗粒磨损的数值模拟

Numerical Simulation on Erosion of Wall by Particles in a 90° Bending Duct of Ventilation Pipeline

基于离散颗粒模型(DPM)对通风除尘管路90°弯管进行气-固两相流动数值模拟,计算了无烟煤颗粒对90°弯管的磨损率,分析了弯管弯径比(弯管曲率半径R与管道直径D之比)、气流入口速度、颗粒粒径及管壁材料等对弯管磨损的影响,并将模拟结果与文献实验值及经验公式计算值进行比较.结果表明,模拟结果和经验公式计算值及实验数据吻合较好,表明模拟结果基本可信;入口风速和颗粒粒径一定时,弯管的磨损率随弯径比增加先减小后增大,当R/D=3～4时,弯管磨损较小;R/D一定时,90°弯管的磨损率E与速度V的关系式为E=KV1.08～1.32,且V=0～5 m/s时,磨损率随速度变化较小,当V>5 m/s时,磨损率随风速变化较大;弯管磨损率与颗粒粒径dp的关系式为E=Kdp2.38～3.01,且R/D越小,磨损率随颗粒粒径变化越明显.而d_p<5μm时,弯管磨损率几乎为0;管壁材料特性(如布氏硬度)也会影响磨损率,布氏硬度大的材料磨损率较小,而布氏硬度小的材料磨损率较大.

The gas-solid two-phase flow in 90° bending duct of the ventilation and dust removal pipeline was simulated using CFD-DPM, and the erosion rate of the bending duct by anthracite coal particle was calculated, and the influence of the bend diameter R/D ratio of the bending duct, inlet gas velocity, particle size and the materials properties of the duct wall on the erosion was also analyzed. And, the results of numerical simulation were compared with those of experiment and by empirical formula in the literature. The results show that the numerical simulation results match the experimental data and empirical formula calculation values, which indicates that the numerical simulation results are probably credible. When the inlet gas velocity and the particle size are fixed, the erosion rate of the bending duct decreases first and then increases with increasing R/D. When R/D is 3～4, the erosion rate is relatively small, the relational expression between the erosion rate and the inlet gas velocity is E=KV1.08～1.32 when the bend diameter ratio is constant, and the inlet gas velocity is 0～5 m/s, the change of the erosion rate with the inlet gas velocity is small, but when the inlet gas velocity is greater than 5 m/s, the trend is opposite. The relational expression between the erosion rate and the particle size is E=Kdp2.38～3.01. The smaller the bend diameter ratio, the more obvious the erosion rate changes with the dust particle size. And when the dust particle size is smaller than 5 μm, the erosion rate is almost zero. In addition, the materials properties of the duct wall（such as brinell hardness） also influence the erosion rate, and the erosion rate of the material with the great brinell hardness is lower than that of the material with the small brinell hardness.