Gas explosion is a process involving complex hydrodynamics and chemical reactions.In order to investigate the interaction between the flame behavior and the dynamic overpressure resulting from the explosion of a premi...Gas explosion is a process involving complex hydrodynamics and chemical reactions.In order to investigate the interaction between the flame behavior and the dynamic overpressure resulting from the explosion of a premixed gasoline-air mixture in a confined space,a large eddy simulation(LES)strategy coupled with sub-grid combustion model has been implemented.The considered confined space consists of a long duct and four branches symmetrically distributed on both sides of the long duct.Comparisons between the simulated and experimental results have been considered with regard to the flame structure,flame speed and overpressure characteristics.It is shown that the explosion process can qualitatively be reproduced by the numerical simulation.Due to the branch structure,vortices are generated near the joint of the branch and long duct.Vortices rotate in opposite directions in the different branches.When the flame propagates into the branch,the flame front is influenced by the flow field structure and becomes more and more distorted.The overpressure displays a similar behavior in the two branches which have a different distance from the ignition point.It is finally shown that the overpressure change law can directly be put in relation with the shape of flame front.展开更多
Determination of the capacity for explosion of gas mixtures in a sealed area is very important for mining engineers.If this capacity is high,it would be very dangerous for rescue workers to proceed with their rescue o...Determination of the capacity for explosion of gas mixtures in a sealed area is very important for mining engineers.If this capacity is high,it would be very dangerous for rescue workers to proceed with their rescue operations.A number of methods have been developed to determine the capacity for explosion of gas mixtures in sealed areas.One of the more popular methods is the Coward explosive triangle,published by Coward.He presented a fast and easy way to determine the capacity for explosion of gas mixtures,which has proved to be a very useful tool for mining engineers and members of rescue teams.However,due to few drawbacks in this method;potential errors would be introduced when it is applied.In a brief introduction we first describe the Coward method and then,we propose and discuss new calibrated explosive triangles.We demonstrate the method in two case studies where we compare our results with those of the old model.The results indicate that the calibrated method have improved accuracy and reliability.Therefore,assessments can be made more accurately.展开更多
基金supported by the National Outstanding Youth Science Fund Project of National Natural Science Foundation of China[grant numbers 51704301]Foundation Strengthening Project of China[grant numbers 2019-JCJQ-JJ-024].
文摘Gas explosion is a process involving complex hydrodynamics and chemical reactions.In order to investigate the interaction between the flame behavior and the dynamic overpressure resulting from the explosion of a premixed gasoline-air mixture in a confined space,a large eddy simulation(LES)strategy coupled with sub-grid combustion model has been implemented.The considered confined space consists of a long duct and four branches symmetrically distributed on both sides of the long duct.Comparisons between the simulated and experimental results have been considered with regard to the flame structure,flame speed and overpressure characteristics.It is shown that the explosion process can qualitatively be reproduced by the numerical simulation.Due to the branch structure,vortices are generated near the joint of the branch and long duct.Vortices rotate in opposite directions in the different branches.When the flame propagates into the branch,the flame front is influenced by the flow field structure and becomes more and more distorted.The overpressure displays a similar behavior in the two branches which have a different distance from the ignition point.It is finally shown that the overpressure change law can directly be put in relation with the shape of flame front.
文摘Determination of the capacity for explosion of gas mixtures in a sealed area is very important for mining engineers.If this capacity is high,it would be very dangerous for rescue workers to proceed with their rescue operations.A number of methods have been developed to determine the capacity for explosion of gas mixtures in sealed areas.One of the more popular methods is the Coward explosive triangle,published by Coward.He presented a fast and easy way to determine the capacity for explosion of gas mixtures,which has proved to be a very useful tool for mining engineers and members of rescue teams.However,due to few drawbacks in this method;potential errors would be introduced when it is applied.In a brief introduction we first describe the Coward method and then,we propose and discuss new calibrated explosive triangles.We demonstrate the method in two case studies where we compare our results with those of the old model.The results indicate that the calibrated method have improved accuracy and reliability.Therefore,assessments can be made more accurately.
