Study On The Construction Of The Mathematical Model Of The Minimum Ignition Energy Of Gas Explosion And The Coupling Of Parameters

Gas explosion accidents occur frequently in the coal mining industry,which has caused non-negligible losses to the national economy.How to pre-control and prevent such accidents has become a hot spot of scientific research in the field of safety.Aiming at the gas explosion process with multi-factor coupling,perfecting the basic theoretical system of explosion ignition and effect characteristics is of great practical significance to the development of explosion pre-control and prevention technology.This paper puts forward the idea of flame propagation layer by layer according to the basic theory of thermodynamics.The complex and changeable combustion process is represented as the superposition effect of multiple flame propagation.Combined with the method of differentiating and summing integral,a mathematical model for calculating the minimum ignition energy of combustible gas is established.The explosion characteristic parameters at the initial stage of ignition are captured by a 20L spherical closed explosion experimental system in a high-speed camera environment,and the reliability of the model is verified by an example.A minimum ignition energy prediction method with 95%accuracy and suitable for any concentration of combustible gas and ideal powder(uniform distribution of powder particles)is formed.The characteristics and parameter rules of the model are analyzed by basic chemical analysis,and the applicability of the model in the field of combustible powder is evaluated.Molecular structure and bond energy play an important role in the minimum ignition energy.The more complex the molecular structure is,the higher the bond energy is and the greater the minimum ignition energy is.For organic homologues,molecular weight plays an important role in the minimum ignition energy.The smaller the molecular weight,the greater the minimum ignition energy.The exothermic and heat transfer capacity of fuel molecules,the heat transfer area and the number of molecules affect the dependence of flame on external energy.the smaller the dependence,the less energy required for fuel to be ignited.Among them,the enhancement of exothermic and heat transfer capacity will weaken the dependence of flame on external energy,the increase of the number of fuel molecules will weaken the dependence of flame on external energy,and the increase of heat transfer area will increase the dependence of flame on external energy.In particular,the near-linear relationship between the flame induction period and the minimum ignition energy is a non-accidental phenomenon in the process of combustible gas explosion.The excess ignition energy is introduced to express the difference between the actual ignition energy and the minimum ignition energy,which has both physical and chemical effects on the flammable gas explosion.The physical action leads to the increase of the explosion pressure peak value and the explosion intensity,while the chemical action leads to the advance of the explosion pressure peak value and the acceleration of the explosion pressure rise rate.As a result,two characteristic parameters,intensity effect,and catalytic effect are proposed to express the degree of physical and chemical action.A 20L spherical closed explosion experimental system under an electronic ignition environment was used to explore the effects of volume fraction and ignition energy on intensity effect and catalytic effect.There is a positive linear correlation between the strength effect and the excess ignition energy.There is a non-linear negative correlation between the catalytic effect and the excess ignition energy.The more the number of fuel molecules is,the weaker the effect of excess ignition energy is,and the smaller the intensity effect and catalytic effect are.This paper has important theoretical guiding significance and engineering application value for coal mine safety production.On the one hand,the idea of flame propagation layer by layer provides a new idea for simplifying the problem of heat and mass transfer.On the other hand,the mathematical model of gas explosion pressure and minimum ignition energy provides a new direction for the development of explosion early warning and monitoring technology and new prevention and control facilities.