An experimental system for monitoring the acoustic signals generated in coal during gas sorption and/or desorption was designed and the acoustic signals were observed under different gas pressures. The experimental re...An experimental system for monitoring the acoustic signals generated in coal during gas sorption and/or desorption was designed and the acoustic signals were observed under different gas pressures. The experimental results show that signals generated by the coal during gas adsorption are attenuated over time. Also, the signals are not continuous but are impulsive. The intensity of the signals generated during gas desorption is far smaller than that observed during adsorption. The signal seen during desorption remains essentially stable. Cycles of sorption and desorption cause acoustic emission signals that exhibit a memory effect, which depends upon the maximum gas pressure the sample was exposed to in earlier cycles. Lower pressures in subsequent cycles, compared to the maximum adsorption pressure in previous cycles, cause both the energy and impulse frequency to be lower than previously. On the contrary, a gas adsorption pressure that exceeds the maximum pressure seen by the sample during earlier cycles causes both the energy and impulse frequency to be high.展开更多
基金provide by the National Natural Science Foundation of China (Nos. 40804070, 50904067 and51104156)the Research Fund of The State Key Laboratory of Coal Resources and Mine Safety in CUMT (No. SKLCRSM09X01)+2 种基金the International Scientific and Technological Cooperation Projects(No. 2008DFB70100)the Foundation for the Author of National Excellent Doctoral Dissertation of China (No. 201055)the Program for New Century Excellent Talents in University (No. NCET-10-0768)
文摘An experimental system for monitoring the acoustic signals generated in coal during gas sorption and/or desorption was designed and the acoustic signals were observed under different gas pressures. The experimental results show that signals generated by the coal during gas adsorption are attenuated over time. Also, the signals are not continuous but are impulsive. The intensity of the signals generated during gas desorption is far smaller than that observed during adsorption. The signal seen during desorption remains essentially stable. Cycles of sorption and desorption cause acoustic emission signals that exhibit a memory effect, which depends upon the maximum gas pressure the sample was exposed to in earlier cycles. Lower pressures in subsequent cycles, compared to the maximum adsorption pressure in previous cycles, cause both the energy and impulse frequency to be lower than previously. On the contrary, a gas adsorption pressure that exceeds the maximum pressure seen by the sample during earlier cycles causes both the energy and impulse frequency to be high.
