School of Safety and Emergency Management Engineering, Taiyuan University of Technology

为进一步改善液滴雾化润湿性能、提高微细粉尘防治效率，以疏水性晋城无烟煤煤尘为例，采用磁电耦合表面张力交叉实验、球形液滴−粉尘颗粒物碰撞Comsol两相流数值模拟及降尘效率对比实验相结合的手段，将液滴碰撞球形颗粒的动力学特征应用到喷雾降尘中，研究了磁化荷电液滴捕捉煤尘颗粒的动力学行为，揭示了磁化荷电水雾降尘机理。结果表明：磁化、荷电、磁电耦合作用对液滴浸润性改善能力大小关系为磁电耦合作用>荷电作用>磁化作用，且存在最佳耦合参数，在磁化强度为300 MT、荷电电压8 kV时，液滴表面张力达到最小值9.20 mN/m；在液滴与球形煤尘颗粒碰撞过程中，磁电耦合作用消除了相对碰撞速度和粒径比变化对液滴捕捉煤尘颗粒的不利影响，磁化荷电后的液滴在煤尘颗粒表面无回弹现象；相较于普通水滴，磁化荷电液滴更易分裂并产生卫星液滴，即雾化性能提高，微细液滴质量浓度增大，液滴与煤尘颗粒碰撞概率增大；磁化荷电液滴表面张力和黏度减小，在煤尘颗粒表面铺展范围扩大了44.98%，润湿性能显著提高。通过对比磁化荷电水雾与普通水雾的降尘效果，发现磁化荷电水雾全尘、呼吸性粉尘平均降尘效率分别达到94.07%、82.69%，其效率分别提高了39.16%、42.29%。

In order to further improve the atomization and wetting performance of droplets, and increase the control efficiency of fine dust, in this study, the non-wetting anthracite dust in the Jincheng Mine was taken as an example. The method of the combination of the crossover experiments about magnetoelectric property coupled by surface tension, the two-phase flow numerical simulation on spherical droplet-dust particle collision by Comsol and the experiment of dust-reduction efficiency comparison was adopted. By applying the kinetic characteristics of spherical droplet-dust collision to spray dust reduction, the kinetic behaviors of magnetized and charged droplets capturing coal dust particles were investigated, and the dust suppression mechanism of magneto-electric coupled water mist was revealed. The results show that there is no linear positive correlation between magnetisation strength and droplet surface tension. The relationship between magnetisation, charge and magneto-electric coupling ability to improve droplet wettability is as follows: magneto-electric coupling>charge>magnetisation. For magnetoelectric spray, there exist optimum coupling parameters. When the magnetization intensity is 300 MT and the charge voltage is 8 kV, the surface tension of the droplet is the minimum (9.20 mN/m). In the process of collision between spherical droplets and coal dust particles, magneto-electric coupling eliminates the adverse effects of changes in relative collision velocity and particle-size-ratio on that droplets capture coal dust particles. At this time, the magnetoelectric droplets will not rebound on the surface of the coal dust particles. Compared with the normal droplets, the magnetoelectric droplets are more likely to split and produce satellite droplets. Therefore, the atomization performance is improved, the concentration of fine droplets is increased and the probability of the collision between droplets and coal dust particles is increased. Moreover, the surface tension and viscosity of the magnetoelectric droplets are reduced, and the spreading range on the surface of coal dust particles is expanded by 44.98%, which improves the atomization and wetting performance of droplets. By comparing the dust reduction effect of magnetoelectric water mist with ordinary water mist, it was found that the reduction efficiency of the full dust and the respirable dust for magneto-electric water mist reached 94.07% and 82.69% respectively, which increased by 39.16% and 42.29% respectively.

国家自然科学基金资助项目(52174195，52274220)

熊光婷，葛少成，孙丽英，等. 磁化荷电液滴除尘机理及碰撞浸润煤尘数值仿真[J]. 煤炭学报，2023，48(9)：3441−3450.

XIONG Guangting，GE Shaocheng，SUN Liying，et al. Numerical simulation on dust removal mechanism of
magnetoelectric droplets and collision wetting coal dust[J]. Journal of China Coal Society，2023，48(9)：3441−3450.