热源及空隙率对上部松散煤体影响的试验研究

为研究热源及空隙率在松散煤体内自卷吸供氧过程中对上部松散煤体的影响,利用自制的高温松散煤体自吸氧试验装置,测试了热源温度分别为30℃、60℃、90℃、120℃、150℃、200℃时,粒径分别为1~3 mm、3~5 mm、5~7 mm、7~10 mm、10~15 mm的松散煤体的内部温度,计算了不同热源强度下松散煤体内部的浮升力。结果表明:1)当热源温度及煤体空隙率一定时,各测点温度分布基本呈线性变化规律,但是随着热源温度不断升高,线性变化规律减弱;2)空隙率一定时,随热源温度升高,松散煤体内各测点温度增大,各测点的温度梯度也增大;3)当热源温度值一定时,随煤体空隙率的增大,同一测点的温度值整体增大;4)随热源温度升高,煤体内各相邻测点区间浮升力大致呈指数规律变化;浮升力随热源升高而增大,不同测点区间的浮升力影响因素不同;当热源温度一定时,距离热源区间越远,煤体浮升力越小。

Experimental study for the impact of the heating source and porosity on the upper layer of the loose coal seam

This paper attempts to study the impact of the heating source and porosity of the upper-layer loose coal on the process of oxygen entrainment.For the study purpose,we have tested the temperature distribution of different porosity loose coals at different temperatures of heating source for the oxygen entrainment with the experimental device.To be specific,we have chosen the heating sources with its temperature range at 30 ℃,60 ℃,90 ℃,120 ℃,150 ℃,200 ℃,correspondingly,whereas we have to deal with the coal samples with their particle sizes being of 1 mmto3 mm,3 mmto5 mm,5 mmto7 mm,7 mm to 10 mm,10 mm to 15 mm,respectively.For the research purpose,we have managed to make a simulated experiment to test the oxygen entrainment of loose coal seam while the heating process of the coal seam keeps going on.And,later,we have worked out the internal buoyancy force under the different conditions based on the data gained from the aforementioned experiments.The results of our experiments indicate that the impacts of the heating source and porosity on the upper loose coal seam are quite different under the various conditions.For instance,when the heating source temperature and the coal porosity are both unchangeable,the temperature of the measuring points in the coal samples seems to be varying in a linear manner.However,when the temperature of the heating source increases,the trend of the linear change may tend to be weakening.Besides,we have also found that,when the coal porosity remains unchangeable,with the increase of the heating source temperature,the temperature of each measuring point in the loose coal seam tends also to be rising with the temperature gradient of each measuring point rising up as well.What is more,once the temperature of heating source comes to a constant,with the increase of the coal porosity,the temperature of each measuring point would be going up in an overall manner.However,with the increase of the heating source temperature,the buoyancy of the coal particles and the interval between the adjacent measuring points would also tend to change in an exponential ratio,consequently.Nevertheless,the influential factors that affect the buoyancy of the different intervals tend to be quite different from each other.Therefore,when the temperature of the heating source arrives at a constant,a new situation will turn up,that is,the farther the temperature of the heating source away from the interval,the smaller the buoyancy in the coal body would be.