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International Journal of Mining Science and Technology 2021年第2期31卷 253-263页

作者： Weitao Hou Hanpeng Wang Liang Yuan Wei Wang Yang Xue Zhengwei Ma Geotechnical and Structural Engineering Research Center Shandong UniversityJinan 250061China School of Qilu Transportation Shandong UniversityJinan 250061China School of Mining and Safety Engineering Anhui University of Science and TechnologyHuainan 232001China

Coal and gas outburst is a violent disaster driven by released energy from gas *** initial expansion energy of released gas(IEERG)is a new method to predict coal and gas *** this paper,an instrument for IEERG measurement was *** with previous setups,the new one which is equipped with three convergent nozzles and quick-release mechanism gets improved in data acquisition and gas sealing and releasing *** comprehensively know the effect of gas pressure,particle size,and nozzle area on IEERG,a series of experiments were carried out with this new *** variable control test results indicated that the gas pressure-IEERG curves remain the linear trend and the particle size-IEERG curves maintain the negative exponential trend for nozzle areas at 1.13,2.26,and3.39 mm2,*** increase in nozzle area leads to deceases in value of IEERG and absolute value of slope of fitting curves in each *** addition,the orthogonal experiment showed that the influence of gas pressure,nozzle area,and particle size on IEERG decreases in *** gas pressure had a marked impact on *** work offers great importance in improving the accuracy of prediction of coal and gas outburst.

关键词： Coal and gas outburst Initial expansion energy of released gas gas pressure Particle size Nozzle area

Effects of gas pressure on plasma characteristics in dual frequency argon capacitive glow discharges at low pressure by a self-consistent fluid model

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Chinese Physics B 2017年第12期26卷 361-370页

作者：赵璐璐刘悦 Tagra Samir Key Laboratory of Materials Modification by Laser Ion and Electron Beams (Ministry of Education) School of PhysicsDalian University of Technology School of Information Science and Engineering Dalian Polytechnic University

A self-consistent fluid model for dual radio frequency argon capacitive glow discharges at low pressure is established. Numerical results are obtained by using a finite difference method to solve the model numerically, and the results are analyzed to study the effect of gas pressure on the plasma characteristics. It shows that when the gas pressure increases from 0.3 Torr （1 Torr=1.33322102 Pa） to 1.5 Torr, the cycle-averaged plasma density and the ionization rate increase; the cycle-averaged ion current densities and ion energy densities on the electrodes electrode increase; the cycle-averaged electron temperature decreases. Also, the instantaneous electron density in the powered sheath region is presented and discussed. The cycle-averaged electric field has a complex behavior with the increasing of gas pressure, and its changes take place mainly in the two sheath regions. The cycle-averaged electron pressure heating, electron ohmic heating, electron heating, and electron energy loss are all influenced by the gas pressure. Two peaks of the electron heating appear in the sheath regions and the two peaks become larger and move to electrodes as the gas pressure increases.

关键词： dual frequency gas pressure glow discharge

Effect of gas pressure on ion energy at substrate side of Ag target radio-frequency and very-high-frequency magnetron sputtering discharge

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Plasma Science and Technology 2022年第2期24卷 162-171页

作者： Weichen Nl Chao YE Yiqing YU Xiangying WANG School of Physics Science and Technology Soochow UniversitySuzhou 215006People's Republic of China Key Laboratory of Thin Films of Jiangsu Province Soochow UniversitySuzhou 215006People's Republic of China Medical College Soochow UniversitySuzhou 215123People's Republic of China

The effect of gas pressure on ion energy distribution at the substrate side of Ag target radio-frequency(RF)and very-high-frequency(VHF)magnetron sputtering discharge was *** lower pressure,the evolution of maximum ion energy(E)with discharge voltage(V)varied with the excitation frequency,due to the joint contribution of the ion generation in the bulk plasma and the ion movement across the sheath related to the ion transit sheath timeτiand RF periodτ*** higher pressure,the evolution of E–V relationships did not vary with the excitation frequency,due to the balance between the energy lost through collisions and the energy gained by acceleration in the electric ***,for RF and VHF magnetron discharge,lower gas pressure can have a clear influence on the E–V relationship.

关键词： excitation frequency gas pressure ion energy magnetron sputtering discharge

Response characteristics of gas pressure under simultaneous static and dynamic load:Implication for coal and gas outburst mechanism

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International Journal of Mining Science and Technology 2023年第2期33卷 155-171页

作者： Longyong Shu Liang Yuan Qixian Li Wentao Xue Nannan Zhu Zhengshuai Liu School of Energy and Mining Engineering China University of Mining and Technology-BeijingBeijing 100083China Mine Safety Technology Branch China Coal Research InstituteBeijing 100013China State Key Laboratory of Mining Response and Disaster Prevention and Control in Deep Coal Mines Anhui University of Science&TechnologyHuainan 232001China China Coal Research Institute Beijing 100013China

Coal and gas outbursts are dynamic disasters in which a large mass of gas and coal suddenly emerges in a mining space within a split *** interaction between the gas pressure and stress environment is one of the key factors that induce coal and gas *** this study,first,the coupling relationship between the gas pressure in the coal body ahead of the working face and the dynamic load was investigated using experimental observations,numerical simulations,and mine-site *** was observed that the impact rate of the dynamic load on the gas-bearing coal can significantly change the gas *** faster the impact rate,the speedier the increase in gas ***,the gas pressure rise was faster closer to the impact ***,based on engineering background,we proposed three models of stress and gas pressure distribution in the coal body ahead of the working face:static load,stress disturbance,and dynamic load ***,the gas pressure distribution and outburst mechanism were *** high concentration of gas pressure appearing at the coal body ahead of the working face was caused by the dynamic *** gas pressure first increased gradually to a peak value and then decreased with increasing distance from the working *** increase in gas pressure plays a major role in outburst initiation by resulting in the ability to more easily reach the critical points needed for outburst ***,the stronger the dynamic load,the greater the outburst initiation *** results of this study provide practical guidance for the early warning and prevention of coal and gas outbursts.

关键词： Coal and gas outburst gas pressure Dynamic load Outburst mechanism

Experimental investigations on effects of gas pressure on mechanical behaviors and failure characteristic of coals

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Journal of Rock Mechanics and Geotechnical Engineering 2023年第2期15卷 412-428页

作者： Yi Xue P.G.Ranjith Feng Gao Zhizhen Zhang Songhe Wang State Key Laboratory of Eco-hydraulics in Northwest Arid Region Xi’an University of TechnologyXi’an710048China Deep Earth Energy Laboratory Department of Civil EngineeringMonash UniversityBuilding 60MelbourneVictoria3800Australia State Key Laboratory for Geomechanics and Deep Underground Engineering China University of Mining and TechnologyXuzhou221006China

The mechanical behavior of coal is the key factor affecting underground coal mining and coalbed methane *** this study,triaxial compression and seepage tests were carried out on coal at different gas *** mechanical properties and failure process of coal were studied,as well as the acoustic emission(AE)and strain *** influence of gas pressure on the mechanical parameters of this coal was *** on the conventional energy calculation formula,the pore pressure was introduced through the effective stress formula,and each energy component of coal containing gas was refined *** contribution of gas pressure to the total energy input and dissipation during loading was quantitatively ***,the influence of gas pressure on coal strength was theo-retically analyzed from the perspectives of MohreCoulomb criterion and fracture *** results show that the total absorbed energy comprises the absorbed energy in the axial pressure direction(positive)and in the confining pressure direction(negative),as well as that induced by the pore pressure(initially negative and then positive).The absorbed energy in the axial pressure direction accounts for the main proportion of the total energy absorbed by *** quiet period of AE in the initial stage shortens,and AE activity increases during the pre-peak stage under high gas *** fractal characteristics of AE in three stages are studied using the correlation *** AE process has different forms of self-similarity in various deformation stages.

关键词： Coal gas pressure Acoustic emission(AE) Strain energy Fractal characteristics

Influence of Ground Stress on Coal Seam gas pressure and gas Content

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Fluid Dynamics & Materials Processing 2019年第1期15卷 53-61页

作者： Xuebo Zhang Zhiwei Jia The Collaborative Innovation Center of Coal Safety Production of Henan Province Jiaozuo45400China State Key Laboratory Cultivation Base for gas Geology and gas Control Jiaozuo45400China School of Safety Science&Engineering Henan Polytechnic UniversityJiaozuo45400China

The influence of ground stress was quantitatively analyzed on coal seam gas pressure and gas content in this *** activities in coal mine can result in stress concentration in the coal(rock)body around the mining space,but porosity of the coal seam would not change too ***,gas pressure and gas content in the coal seam are slightly *** showed that the free gas was gradually transformed into adsorbed gas,and the gas adsorption volume was small,and then gas pressure increases roughly linearly when the porosity decreased because of stress ***,when porosity of coal seam reduced to 40%,the amount of adsorbed gas accounted for no more than 10%of coal seam gas content,and the increase of gas pressure did not exceed 15%of the original gas pressure.

关键词： Ground stress coal seam porosity gas pressure gas content stress concentration.

Effect of aeration on fast gas pressure tests

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Mining Science and Technology 2009年第6期19卷 756-760页

作者： CHEN Yu-jia JIANG Cheng-lin LI Xiao-wei TANG Jun WANG Chen YANG Fei-long WANG Fa-kai ZHANG Chao-jie DENG Shu-hua School of Safety Engineering China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

Given the problem of the long time required for testing gas pressure, we propose a fast-test method in which we used a technique of fast borehole sealing and air replenishing. Based on the characteristics of gas emission from boreholes to be tested, we built a theoretical model for calculating parameters during the process of increasing natural pressure and aeration. Using this model, we investigated the effect of different aeration conditions on velocity of pressure tests. The result shows that: 1) aerating air into boreholes can speed up gas pressure tests and 2) the more similar the pressure of the aerated air to the original gas pressure, the smaller the gas volume absorbed by coal and the shorter the time needed in pressure test. A case study in the Lu’an mining area shows that the time needed for gas pressure test is only 4 h using our method of aeration and 29 h under conditions of increasing natural pressure, saving time by 86.2%. This case study also indicates that, by using the aeration method, only one hour is needed for gas pressure to reach a stable state, which breaks the record of the shortest time needed for gas pressure tests in China.

关键词： aeration gas pressure fast test aeration pressure adsorption quantity

Quick determination of gas pressure before uncovering coal in cross-cuts and shafts

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Journal of China University of Mining and Technology 2008年第4期18卷 494-499页

作者： JIANG Cheng-lin WANG Chen LI Xiao-wei CHEN Yu-jia XIE Qing-xue LIU Ying TANG Jun YANG Fei-long WANG Fa-kai DENG Su-hua ZHANG Chao-jie CHENG Song-li LV Shu-wen School of Safety Engineering China University of Mining ＆ Technology Xuzhou Jiangsu 221008 China

The determination of gas pressure before uncovering coal in cross-cuts and in shafts is one of the important steps in pre- dicting coal and gas outbursts. However, the time spent for testing gas pressure is, at present, very long, seriously affecting the ap- plication of outburst prediction techniques in opening coal seams in cross-cuts and shafts. In order to reduce the time needed in gas pressure tests and to improve the accuracy of tests, we analyzed the process of gas pressure tests and examined the effect of the length of boreholes in coal seams in tests. The result shows that 1) the shorter the borehole, the easier the real pressure value of gas can be obtained and 2) the main factors affecting the time spent in gas pressure tests are the length of the borehole in coal seams, the gas emission time after the borehole has been formed and the quality of the borehole-sealing. The longer the length of the bore- hole, the longer the gas emission time and the larger the pressure-relief circle formed around the borehole, the longer the time needed for pressure tests. By controlling the length of the borehole in a test case in the Huainan mining area, and adopting a quick sealing technique using a sticky liquid method, the sealing quality was clearly improved and the gas emission time as well as the amount of gas discharged greatly decreased. Before the method described, the time required for the gas pressure to increase during the pressure test process, was more than 10 days. With our new method the required time is only 5 hours. In addition, the accuracy of the gas pressure test is greatly improved.

关键词： gas pressure sticky liquid sealing quick test cross-cut shaft

Fusion Control of gas pressure and Noise in Sealed Cabin of Manned Spacecraft

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Fusion Control of Gas Pressure and Noise in Sealed Cabin of ...

Dynamic development characteristics of amounts of gas and levels of pressure in the Pan-1 coal mine of Huainan

第32届中国控制与决策会议

作者： Li Zhe An Meizhen ZHANG Qiao DU Zhanchao Yu Hongmiao Beijing Institute of Manned Space System Engineering China Academy of Space Technology Technology and Engineering Center for Space Utilization Chinese Academy of Sciences

The noise environment is an important medical *** order to realize the long-term resistant of astronauts in orbit,it’s necessary to strictly control the noise in the sealed cabin of manned *** the paper,the formula of gas pressure and monopole source is deduced according to theoretical ***,the model of monopole source is established,and the analysis result of the theoretical formula is confirmed by the direct boundary element ***,the simulation analysis results are summarized,and the law that the sound pressure is proportional to the gas pressure is extended to the noise environment in the sealed cabin of manned ***,the method of fusion control of gas pressure and noise in sealed cabin of manned spacecraft is proposed.

关键词： Fusion control Manned spacecraft gas pressure Noise

来源： cnki会议评论

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Mining Science and Technology 2009年第6期19卷 740-744页

作者： WANG Ke-xin FU Xue-hai ZHOU Yan-an HE Ye WE Heng School of Resources ＆ Earth Science China University of Mining ＆ Technology Xuzhou Jiangsu 221116 China gas Research Institute of Huainan Mining Group Huainan Anhui 232000 China

The Pan-1 coal mine located in Huainan municipality, Anhui province, is abundant in coal resources. In order to discover the natural conditions of gas in its coal seams, we inverted the burial history of these coal seams using the software of Easy%Ro method and simulated the development process of gas volumes and pressure of the major coal seams using CBM History Simulation Software. Our analysis shows that the devolution of gas volumes and levels of pressure can be divided into four stages: i.e., a biogas stage (P1-P3), a pyrolysis gas stage (T1-T2), an active gas enrichment stage (T3-K1) and a gas dissipating stage (K2-present). Currently, the average amounts of gas and gas pressure in coal seams Nos. 13-1, 11-2 and 8 of the Pan-1 coal mine are 8.18 m3/t and 2.20 MPa; 3.89 m3/t and 2.47 MPa and 6.35 m3/t and 2.89 MPa, respectively. This agrees very well with current mining data.

关键词： gas volume gas pressure dynamic development numerical simulation Pan-1 coal mine