In order to study the hypotonic and rheological particularity of “three soft” coal seam in west Henan, China, this paper explored the stress and damage characteristics of crack in coal under condition of water injec...In order to study the hypotonic and rheological particularity of “three soft” coal seam in west Henan, China, this paper explored the stress and damage characteristics of crack in coal under condition of water injection fracturing based on ABAQUS platform;The cohesive element in T-P damage evolution criterion was used to describe the approximately linear relationship between crack width and extending distance in soft coal. The simulation results show that stress evolution and crack damage in soft coal is a gradually developing process under condition of water injection fracturing. When the static pressure is 4 - 10 MPa, and the injection time is about 1 - 2 hours, the damage range of crack in soft coal can basically reach an ideal data of 80 - 100 m, and then greatly improve the hypotonic performance of “three soft” coal seam.展开更多
This article presents the evolution law of temperature fields in a large-scale laboratory Underground Coal Gasification reactions using Ulanqab lignite under actual conditions.The results show that in the cultivation ...This article presents the evolution law of temperature fields in a large-scale laboratory Underground Coal Gasification reactions using Ulanqab lignite under actual conditions.The results show that in the cultivation stage of oxidation zone,the main direction of the temperature field expansion is consistent with the crack direction of the coal seam.In the gasification stabilization stage,the main direction of the temperature field expansion is along the channel.The temperature of the coal seam and the overlying rock mass at its interface with the furnace directly above the gasification channel is equivalent to that of the coal seam temperature,and this temperature is much greater than the temperatures observed near both side walls of the gasification channel at the interface.However,temperatures perpendicular to the axis of the gasification channel are similar at a vertical distance of 40 cm away from the interface.The temperature distributions indicate that the transmission of heat through the overlying rock mass is more rapid in the vertical direction than in the horizontal direction.Moreover,some degree of thermal dispersion is observed in the vertical direction near the outlet.The thermal dispersion coefficient is 0.72 and dispersion angle γ is 78.7°.展开更多
文摘In order to study the hypotonic and rheological particularity of “three soft” coal seam in west Henan, China, this paper explored the stress and damage characteristics of crack in coal under condition of water injection fracturing based on ABAQUS platform;The cohesive element in T-P damage evolution criterion was used to describe the approximately linear relationship between crack width and extending distance in soft coal. The simulation results show that stress evolution and crack damage in soft coal is a gradually developing process under condition of water injection fracturing. When the static pressure is 4 - 10 MPa, and the injection time is about 1 - 2 hours, the damage range of crack in soft coal can basically reach an ideal data of 80 - 100 m, and then greatly improve the hypotonic performance of “three soft” coal seam.
基金supported by the National High Technology Research and Development Program of China(No.2011AA050106)Hubei Technological Innovation Special Fund(CN)(No.343-0402-YQN-TWEP).
文摘This article presents the evolution law of temperature fields in a large-scale laboratory Underground Coal Gasification reactions using Ulanqab lignite under actual conditions.The results show that in the cultivation stage of oxidation zone,the main direction of the temperature field expansion is consistent with the crack direction of the coal seam.In the gasification stabilization stage,the main direction of the temperature field expansion is along the channel.The temperature of the coal seam and the overlying rock mass at its interface with the furnace directly above the gasification channel is equivalent to that of the coal seam temperature,and this temperature is much greater than the temperatures observed near both side walls of the gasification channel at the interface.However,temperatures perpendicular to the axis of the gasification channel are similar at a vertical distance of 40 cm away from the interface.The temperature distributions indicate that the transmission of heat through the overlying rock mass is more rapid in the vertical direction than in the horizontal direction.Moreover,some degree of thermal dispersion is observed in the vertical direction near the outlet.The thermal dispersion coefficient is 0.72 and dispersion angle γ is 78.7°.
