Various physical parameters, including gas concentrations (O2, CO, CH4, and H2) and temperatures at dif- ferent air velocities, were determined for full scale wood fires in the Chongqing Coal Research Institute fire t...Various physical parameters, including gas concentrations (O2, CO, CH4, and H2) and temperatures at dif- ferent air velocities, were determined for full scale wood fires in the Chongqing Coal Research Institute fire test tunnel. Both experimental measurements and numerical simulations are discussed. The numer- ical analysis was performed with the computational fluid dynamics software package ''FLUENT''. The results show that the experimental data agree with the simulation results. The results verify that Roberts' theory of burning is correct. They also prove that the air velocity is the key factor that determines the type of combustion. Also, it is shown that secondary disasters are unlikely for oxygen rich combustion with a limited fire load.展开更多
In order to study the mechanism of the dual side roof cutting technology on the composite disaster of gas and coal spontaneous combustion in goaf,a model for the evolution of porosity and permeability in the dual side...In order to study the mechanism of the dual side roof cutting technology on the composite disaster of gas and coal spontaneous combustion in goaf,a model for the evolution of porosity and permeability in the dual side roof cutting working face was constructed.The location of the occurrence of the compound disaster of gas explosion and coal spontaneous combustion under the double-sided roof cutting mode was studied,and the sensitivity of the evolution pattern of the compound disaster area to the amount of air supply and gas gush was summarized.The results indicate that the top cutting pressure relief technology significantly reduces the permeability of porous media,and the sensitivity of the goaf on the intake side to airflow disturbances is significantly reduced.As the volume of air supply increases,the distance between the gas explosion risk area and the coal spontaneous combustion risk area gradually decreases,and the probability of composite disaster areas is 0.The increase of air supply and gas emission makes the gas concentration in the middle and deep goaf increase in an exponential function,and the width of the gas explosion risk area increases gradually.When the outflow reaches 40 m^(3)/min,there is no composite disaster zone,indicating that the rapid increase in outflow inhibits the occurrence of composite disasters.展开更多
基金Financial support for this work provided by the National"Eleventh Five-Year" Key Scientific and Technological Support[Program (No. 2007BAK22B04)2008 independent task (No.SKLCRSM08B12)
文摘Various physical parameters, including gas concentrations (O2, CO, CH4, and H2) and temperatures at dif- ferent air velocities, were determined for full scale wood fires in the Chongqing Coal Research Institute fire test tunnel. Both experimental measurements and numerical simulations are discussed. The numer- ical analysis was performed with the computational fluid dynamics software package ''FLUENT''. The results show that the experimental data agree with the simulation results. The results verify that Roberts' theory of burning is correct. They also prove that the air velocity is the key factor that determines the type of combustion. Also, it is shown that secondary disasters are unlikely for oxygen rich combustion with a limited fire load.
基金supported by the National Natural Science Foundation of China(No.52204090).
文摘In order to study the mechanism of the dual side roof cutting technology on the composite disaster of gas and coal spontaneous combustion in goaf,a model for the evolution of porosity and permeability in the dual side roof cutting working face was constructed.The location of the occurrence of the compound disaster of gas explosion and coal spontaneous combustion under the double-sided roof cutting mode was studied,and the sensitivity of the evolution pattern of the compound disaster area to the amount of air supply and gas gush was summarized.The results indicate that the top cutting pressure relief technology significantly reduces the permeability of porous media,and the sensitivity of the goaf on the intake side to airflow disturbances is significantly reduced.As the volume of air supply increases,the distance between the gas explosion risk area and the coal spontaneous combustion risk area gradually decreases,and the probability of composite disaster areas is 0.The increase of air supply and gas emission makes the gas concentration in the middle and deep goaf increase in an exponential function,and the width of the gas explosion risk area increases gradually.When the outflow reaches 40 m^(3)/min,there is no composite disaster zone,indicating that the rapid increase in outflow inhibits the occurrence of composite disasters.
