为揭示煤尘润湿机理和改进抑尘效果,研究了粒径影响下煤颗粒的动态润湿行为。将煤样破碎筛分为5种不同粒径的煤颗粒,通过低温液氮法和压汞法联合表征煤颗粒孔隙特征,分析不同粒径煤颗粒孔隙分形特征,借助低场核磁共振(LF-NMR)技术从时间和空间尺度分别描述水在润湿煤颗粒过程中的状态变化及动态润湿过程。结果表明:粒径减小,过渡孔、微孔孔径占比增多;粒径过大或过小时,过渡孔、微孔的分形特征不明显;低场核磁共振T2谱图反映了润湿过程中煤颗粒孔隙吸附的水、煤颗粒表面吸附的水和流动的自由水3种状态,定量分析水的时空演变特征,将润湿煤颗粒过程分为煤表面扩散、润湿表面孔隙及持续扩散3个阶段。润湿阶段的明确为提高煤尘润湿效率提供了参考。

To reveal coal-dust wetting mechanism and improve the effect of dust suppression, the dy- namic wetting behavior of coal particles under the influence of particle size is studied. The coal samples from Sijiazhuang are crushed and screened into five different coal particles with different particle sizes. The pore characteristics with different particle sizes are represented by low-temperature liquid nitrogen method and mercury intrusion porosimetry method. The fractal characteristics of coal particles with dif- ferent particle sizes are analyzed. The results show that with the decrease of particle size, the proportion of pore size increases. When the particle size is too large or too small, the fractal characteristics of transi- tion pores and micropores are not transparent. The T 2  spectrum reflects three states of pore-adsorbed wa- ter, coal surface-adsorbed water and free water in the wetting process. The spatio-temporal evolution characteristics of water are quantitatively analyzed, and the process of wetting coal particles is divided into three stages: coal surface diffusion, wetting coal pores and continuous diffusion. The clarity of the wetting stage can provide a paradigm for improving the coal dust wetting efficiency.