水分散失对破碎煤体空隙率变化的影响研究

Study on the influence of water losing on crushed coal porosity

为了研究破碎煤体水分散失规律与空隙率演变特征,通过控制水浸煤样粒径、环境温度和初始含水量,开展破碎煤体水分散失与空隙率变化实验测试与分析。结果表明:经过水浸泡后所有煤样宏观体积较干燥状态下的均有所增加,随着水分散失,其空隙率呈现下降趋势,但仍大于干燥状态下的;环境温度越高、粒径越小、初始含水量越大的煤样,水浸后空隙率越大,水分散失阶段具有相同规律;水浸的溶胀效应、受热膨胀效应、颗粒间液桥拉力降低等因素是造成煤体水分散失过程中空隙率变化的主要原因;失水后煤样残留部分的不等量空隙体积导致空隙率增大,煤氧接触面积增大。

In order to study the water loss law and porosity evolution characteristics of broken coal,the ex-perimental test and analysis on the relationship between water loss and porosity change of broken coal were carried out by controlling the environmental temperature,coal sample particle size and initial water content.The results showed that after soaking,the macroscopic volume of all coal samples increased compared with that of dry coal samples,and the porosity decreased with the dispersion of water,which was still larger than that of dry coal samples;The higher the ambient temperature was,the smaller the particle size was and the greater the initial water content was,the greater the porosity was after water immersion,and the same law still existed in the stage of water loss;The swelling effect of water immersion,the effect of thermal expan-sion and the decrease of liquid bridge tension between particles were the main causes of the change of void ratio in the process of coal moisture loss;For the coal sample after water loss,the residual part had unequal void volume,resulting in the increase of void ratio and coal oxygen contact area.