The process of explosion venting to air in a cylindrical vent vessel connected to a duct, filling with a stoichiometric methane-oxygen gas mixture, was simulated numerically by using a colocated grid SIMPLE scheme bas...The process of explosion venting to air in a cylindrical vent vessel connected to a duct, filling with a stoichiometric methane-oxygen gas mixture, was simulated numerically by using a colocated grid SIMPLE scheme based on k-epsilon turbulent model and Eddy-dissipation combustion model. The characteristics of the combustible cloud, flame and pressure distribution in the external flow field during venting were analyzed in terms of the predicted results.The results show that the external explosion is generated due to violent turbulent combustion in the high pressure region within the external combustible cloud ignited by a jet flame. And the turbulence and vortex in the external flow field were also discussed in detail. After the jet flame penetrating into the external combustible cloud, the turbulent intensity is greater in the regions with greater average kinetic energy gradient, rather than in the flame front; and the vortex in the external flow field is generated primarily due to the baroclinic effect, which is greater in the regions where the pressure and density gradients are nearly perpendicular.展开更多
This study involved the construction and explosion of a large-scale(80-meter-long)underdrain and detailed investigations of the damaging impacts of a gas explosion to provide an experimental foundation for similarity ...This study involved the construction and explosion of a large-scale(80-meter-long)underdrain and detailed investigations of the damaging impacts of a gas explosion to provide an experimental foundation for similarity modeling and infrastructural designs.The experiment vividly recreated the scene and explosion damage of the"11.22″explosion accident in Qingdao,China,thus allowing for evaluations of the movements and destruction of the cover plates.The damage mechanism was determined by analyzing the overpressure curves inside and outside the underground canal.It was determined that the cover plates were first lifted by the precursor wave,which induced a maximum overpressure of 0.06 MPa and resulted in explosion venting.The pressure entered the deflagration stage at the end of the explosion.The combustion wave overpressure reached 3.115 MPa close to the initiation point,and had a significant influence on the projectile energy of the cover plates there.Overall,64%of the cover plates were only affected by the precursor wave,while 36%of the cover plates were subjected to both the precursor wave and the combustion wave;these cover plates were severely damaged.The results of this study provide fundamental insights relevant to the prevention and control of underdrain gas explosions.展开更多
Due to the influence of many factors,the overpressure-time history load model of vented gas explosions is difficult to describe and is not conducive to further structural design.Based on vented gas explosion test data...Due to the influence of many factors,the overpressure-time history load model of vented gas explosions is difficult to describe and is not conducive to further structural design.Based on vented gas explosion test data,this paper obtains three typical overpressure-time history curves and puts forward a new semi-empirical model-double hump model that considers gas concentration and venting pressure,and gives a formula for peak pressure and overpressure-time history model.The scientificity of the model is then verified by the total impulse in the load.The model is able directly reflect the load characteristics,provide reference for calculating key parameters of a vented gas explosion and provide information on the structural response under the load.The model thereby has the potential to help reduce the impact of gas explosion disasters.展开更多
Some characteristics of interior explosions within a cabin structure with a venting hole are investigated.It may simulate a warhead explosion inside a cabin following its penetration through the cabin wall.The study i...Some characteristics of interior explosions within a cabin structure with a venting hole are investigated.It may simulate a warhead explosion inside a cabin following its penetration through the cabin wall.The study includes both experimental and theoretical analyses of the problem.The experimental investigation comprises of two types of explosives at the center of the cabin.The pressure distributions at diferent locations on the cabin wall are obtained.The efect of internal shock reflection is analyzed by using the method of images(MOI).It is found that the geometric symmetries can cause the multiple reflected shocks to converge with strength comparable to the initial free shock.展开更多
文摘The process of explosion venting to air in a cylindrical vent vessel connected to a duct, filling with a stoichiometric methane-oxygen gas mixture, was simulated numerically by using a colocated grid SIMPLE scheme based on k-epsilon turbulent model and Eddy-dissipation combustion model. The characteristics of the combustible cloud, flame and pressure distribution in the external flow field during venting were analyzed in terms of the predicted results.The results show that the external explosion is generated due to violent turbulent combustion in the high pressure region within the external combustible cloud ignited by a jet flame. And the turbulence and vortex in the external flow field were also discussed in detail. After the jet flame penetrating into the external combustible cloud, the turbulent intensity is greater in the regions with greater average kinetic energy gradient, rather than in the flame front; and the vortex in the external flow field is generated primarily due to the baroclinic effect, which is greater in the regions where the pressure and density gradients are nearly perpendicular.
基金The authors gratefully acknowledge financial support given by the National 135 Key R and D Projects(Grant Nos.2018YFF0301000)as well as from the National Science Foundation of China(Grant Nos.71861167002,51834007).
文摘This study involved the construction and explosion of a large-scale(80-meter-long)underdrain and detailed investigations of the damaging impacts of a gas explosion to provide an experimental foundation for similarity modeling and infrastructural designs.The experiment vividly recreated the scene and explosion damage of the"11.22″explosion accident in Qingdao,China,thus allowing for evaluations of the movements and destruction of the cover plates.The damage mechanism was determined by analyzing the overpressure curves inside and outside the underground canal.It was determined that the cover plates were first lifted by the precursor wave,which induced a maximum overpressure of 0.06 MPa and resulted in explosion venting.The pressure entered the deflagration stage at the end of the explosion.The combustion wave overpressure reached 3.115 MPa close to the initiation point,and had a significant influence on the projectile energy of the cover plates there.Overall,64%of the cover plates were only affected by the precursor wave,while 36%of the cover plates were subjected to both the precursor wave and the combustion wave;these cover plates were severely damaged.The results of this study provide fundamental insights relevant to the prevention and control of underdrain gas explosions.
基金The authors gratefully acknowledge the financial support from Natural Science Foundation of Jiangsu Province of China(Grant No.BK20180081)National Key R&D Program of China(Great No.2020YFB2103300)National Basic Research Program of China(973 Program)(Grant No.2015CB058000).
文摘Due to the influence of many factors,the overpressure-time history load model of vented gas explosions is difficult to describe and is not conducive to further structural design.Based on vented gas explosion test data,this paper obtains three typical overpressure-time history curves and puts forward a new semi-empirical model-double hump model that considers gas concentration and venting pressure,and gives a formula for peak pressure and overpressure-time history model.The scientificity of the model is then verified by the total impulse in the load.The model is able directly reflect the load characteristics,provide reference for calculating key parameters of a vented gas explosion and provide information on the structural response under the load.The model thereby has the potential to help reduce the impact of gas explosion disasters.
基金the Defense Industrial Technology Development Program(No.A1420080184)the Fundamental Research Funds for the Central Universities of China(No.2011YB08)
文摘Some characteristics of interior explosions within a cabin structure with a venting hole are investigated.It may simulate a warhead explosion inside a cabin following its penetration through the cabin wall.The study includes both experimental and theoretical analyses of the problem.The experimental investigation comprises of two types of explosives at the center of the cabin.The pressure distributions at diferent locations on the cabin wall are obtained.The efect of internal shock reflection is analyzed by using the method of images(MOI).It is found that the geometric symmetries can cause the multiple reflected shocks to converge with strength comparable to the initial free shock.