Taking briquette as studied objects

taking gas flow speed of briquette as studied parameters

the gas flow characteristics of coal sample is studied under the complete stress-strain and unloading axial stress in linear elastic stage; the comparative analysis is done by comparing the gas flow characteristics of loading stage and unloading stage. The results show: the special stress point which makes the gas flow speed minimum appeared in gas flow curve of loading stage

and it belongs to the late of linear elastic stage. In the process of unloading axial stress in linear elastic stage

the reverse trend is shown between stress-stain curve and gas flow characteristical curve; the positive trend is shown between gas flow speed and initial gas flow speed of coal sample; the variation law of gas flow speed is more complex as the addition of strength

only the part of gas flow law is reproduction in the process of unloading axial stress. The laws of gas flow are different in the process of loading stage and unloading stage; the former is uniform change of two stages

the latter is hyperbolic. The influence caused by stress change on gas flow law is more sensitive; it is more obvious in local part of unloading stage.