In order to achieve the safe mining in Sanshandao Gold Mine,five schemes of secure pillar group are designed.Using the method of the renormalization group,the failure mechanism of the pillar group is explored,and the ...In order to achieve the safe mining in Sanshandao Gold Mine,five schemes of secure pillar group are designed.Using the method of the renormalization group,the failure mechanism of the pillar group is explored,and the safety factor of the pillar system is also obtained.The displacement characteristics,stress-strain laws,distribution of plastic zone and damage range of different pillar group are analyzed using numerical calculation software FLAC3D.To determine a reasonable pillar group scheme,the pillar stability and roof deformation are utilized to evaluate the safety of the pillar group.In addition,the theory of fuzzy comprehensive evaluation is adopted to verify the optimal scheme.The pillar group with the lowest roof deformation value is chosen as the optimal plan,which renders a factor of safety of 2.06 for the pillar group.According to this scheme,pillars with the width of 10 m are set along the strike of undersea deposit with the interval of 50 m.Rib pillars of 15 m in width are set at the location of the exploration line of 127,151 and 167.The analysis can be used to provide guidance for optimal design of pillar structures in undersea mining.展开更多
Crimped ribbon flame arresters are important safety devices in the chemical industry, especially for the danger- ous situations. Although proper design of arresters by the numerical simulation method is promising, its...Crimped ribbon flame arresters are important safety devices in the chemical industry, especially for the danger- ous situations. Although proper design of arresters by the numerical simulation method is promising, its reliabil- ity and accuracy are dependent upon the mathematical model. In this work, an integrated mathematical model for the microchannel in the crimped ribbon flame attesters was set up; the fluid flow behavior and the sensitiv- ities of four chemical kinetics mechanisms of propane-air on the accuracy were analysed. It is shown that turbu- lence is predominant in the microchannel of the crimped ribbon flame arresters under the defiagration and detonation conditions, and a new quenching criterion for the numerical simulation is proposed. The kinetics mechanism of Mansouri et al. among the four ones is the most accurate due to the best agreement of the pre- dicted outlet temperature at the experimental flameproof velocity with the autoignition temperature of propane-air. The species mass fraction profiles and the temperature distribution, which are too difficult to mea- sure due to the tiny dimension of the microchannel in experiments, are captured. The fundamental insights into chemical reactions and heat loss are well portrayed. It can be concluded that the integrated mathematical model established in this work can be used as a reliable tool for modeling, selecting and designing such type of crimped ribbon flame attesters with the propane-air medium in the future.展开更多
基金Project(41630642)supported by the Key Project of National Natural Science Foundation of ChinaProjects(51674288,11402311)supported by the National Natural Science Foundation of China
文摘In order to achieve the safe mining in Sanshandao Gold Mine,five schemes of secure pillar group are designed.Using the method of the renormalization group,the failure mechanism of the pillar group is explored,and the safety factor of the pillar system is also obtained.The displacement characteristics,stress-strain laws,distribution of plastic zone and damage range of different pillar group are analyzed using numerical calculation software FLAC3D.To determine a reasonable pillar group scheme,the pillar stability and roof deformation are utilized to evaluate the safety of the pillar group.In addition,the theory of fuzzy comprehensive evaluation is adopted to verify the optimal scheme.The pillar group with the lowest roof deformation value is chosen as the optimal plan,which renders a factor of safety of 2.06 for the pillar group.According to this scheme,pillars with the width of 10 m are set along the strike of undersea deposit with the interval of 50 m.Rib pillars of 15 m in width are set at the location of the exploration line of 127,151 and 167.The analysis can be used to provide guidance for optimal design of pillar structures in undersea mining.
基金Supported by the National Key Research and Development Program of China(2016YFB0301701)the National Natural Science Foundation of China(21706268+4 种基金9143411421376254)the Postdoctoral Science Foundation of Qingdao Municipal Government(Y7330419DM)the Instrument Developing Project of the Chinese Academy of Sciences(YZ201641)State Key Laboratory of Safety and Control for Chemicals of China
文摘Crimped ribbon flame arresters are important safety devices in the chemical industry, especially for the danger- ous situations. Although proper design of arresters by the numerical simulation method is promising, its reliabil- ity and accuracy are dependent upon the mathematical model. In this work, an integrated mathematical model for the microchannel in the crimped ribbon flame attesters was set up; the fluid flow behavior and the sensitiv- ities of four chemical kinetics mechanisms of propane-air on the accuracy were analysed. It is shown that turbu- lence is predominant in the microchannel of the crimped ribbon flame arresters under the defiagration and detonation conditions, and a new quenching criterion for the numerical simulation is proposed. The kinetics mechanism of Mansouri et al. among the four ones is the most accurate due to the best agreement of the pre- dicted outlet temperature at the experimental flameproof velocity with the autoignition temperature of propane-air. The species mass fraction profiles and the temperature distribution, which are too difficult to mea- sure due to the tiny dimension of the microchannel in experiments, are captured. The fundamental insights into chemical reactions and heat loss are well portrayed. It can be concluded that the integrated mathematical model established in this work can be used as a reliable tool for modeling, selecting and designing such type of crimped ribbon flame attesters with the propane-air medium in the future.
