Research On Explosive Characteristics Of Combustible Gasin Wells Within The Restricted Space

Combustible gas explosion in city wells within the restricted space is one of the forms of disaster in the field of urban security,In recent years,combustible gas explosion accidents in city wells within the restricted space occur frequently,urban residents caused serious personal safety and property damage,and even lead to disastrous consequences.Therefore,the study of gas explosion characteristics inwells within the restricted space is of great practical significance and scientific research value for the prevention and control of such catastrophic accidents.The innovation and main conclusions of the paper are:(1)The main components of the gas in city wells are determined.The re sultsshow that the gas in the city wells contains CH4,H2 S,CO2,CO,SO2,NOX,H2,NH3,among them,the content of CO,SO2,NOX,H2 and NH3 is small,alm ost zero,therefore,the main harmful gas in city wells is the CH4,H2 S,CO2,which accounts for larger proportion.(2)The feasibility of FLACS numerical simulation method is verified.Using 20 L spherical explosion container to carry out combustible gas explosion experiment,at the same time,Flacs software was used to simulate the gas explosion process in 20 L spherical explosion container under the same operating conditions.The comparison of experiment and simulation results fully verify the feasibility of the numerical simulation method.And then the numerical simulation method is used to study the gas explosion characteristics in city wells within the restricted space.(3)Obtained the combustible gas explosion lawin wells.Inert gas CO2 can effectively prevent the methane combustion explosion reaction to the positive direction,and increase the concentration of reaction product;The maximum explosive pressure of the combustible gas inwells within the restricted space exhibits an approximate linear relationship with the initial pressure;The closer the ignition position is to the closed end,the more violent the explosion;The explosion pressure generated in the open position of the manhole is smaller than in the closed state,the flame propagation velocity is greater than the closed state.The vent makes the part of the combustible gas and pressure released during the explosion,the role is similar to the pressure relief device;The cross-section changes,trends,layout of Obstruction will affect the explosion pressure field and velocity field.The flame propagation velocity and the explosion pressure when the obstacle is staggered are larger than when the obstacle is placed in parallel.(4)From the control of combustible gas in wells produced in large quantities,gathered and improve the wells explosion prevention management measures in two aspects of in-depth analysis,targeted to put forward countermeasures to prevent gas explosion in wells.