Research Of Explosion Resistant Characteristic In In-line Crimped-ribbon Flame Arrester

Modern industry is developing rapidly,thus,research on prevention and suppression of gas explosion of industrial medium has become an academic frontier project.The quenching process of the flame in the arrester element is concerned with the flow state transition and the heat transfer issues,which is a hot and difficult topic in this field.This paper focuses on the experiments alongside with theory and numerical simulation on the explosion resistance processes in the in-line crimped-ribbon flame arresters.The main content and conclusions of this paper are as follows.(1)A high-precision experimental system of gas explosion and explosion resistance was set up in a straight horizontal pipeline,which included gas mixing equipment,sensor measurement system and data acquisition device.A self-designed flame sensor had been adopted,with its own response time of 10(?s.Thus the high speed flame signal could be recognized effectively.The maximum error of the static gas mixing was 0.1%and the flow rate was not less than 1 m3/min;the maximum error of the dynamic gas mixing was 0.2%,as required.(2)Propane,ethylene,and hydrogen-air mixtures deflagration resistance processes in in-line crimped-ribbon flame arresters were investigated.The results indicate that,a decrease in porosity is able to enhance the front flame speed,although the flame speed tends to increase progressively,the arrester performance improves.The flame speed tended to decrease progressively as the thickness of the arrester element increased,which had a strong ability to stop the flame.A mathematical model was developed to describe the propagation and quenching of the deflagration flame in in-line flame arresters.The flame quenching process in the arrester element was analyzed,which showed that the quenching length of deflagration flame exponentially increased as porosity grew.Combining the experimental and numerical simulation results,the porosity and thickness of the arrester element,as well as the LiD ratio of the pipe were obtained when the quenching failure occurred for gases with different reactivities.The change rule between front explosion pressure,flameproof speed and porosity,element thickness was presented.(3)Propane,ethylene,and hydrogen-air mixtures detonation resistance processes in in-line crimped-ribbon flame arresters were investigated.The results indicate that,the minimum resistance detonation speed is approximately 0.94Vcj for propane,ethylene-air mixtures;the minimum resistance detonation speed is approximately 0.97Vcj for hydrogen-air mixtures.A mathematical model was developed to simulate the propagation and quenching of the detonation wave in in-line flame arresters.The discretization was performed in an NND difference scheme with second-order accuracy.Accordingly,the decoupling process,and quenching rule of the detonation wave in the arrester element were investigated,which showed that the quenching length of detonation wave increased as porosity grew,and the two parameters presented a quadratic function relationship.Combining the experimental and numerical simulation results,values for the porosity and the thickness of the arrester element were obtained when the quenching failure occurred for gases with different reactivities.The change rule between front detonation pressure,porosity,and element thickness was presented.As porosity decreased the pressure peak drop in the arrester element was observed,and the pressure peak value in the element increased with the arrester thickness decreased when detonation wave propagated inside arrester element.All these parameters would increase the inhibitory effect of the detonation wave.(4)The relationship between the flame speed and the front explosion pressure was revealed.The influence of the flame resistance performance on the flame propagation energy characterized by the flame speed and the front explosion was analyzed.By using heat transfer theory,the formula for calculating the deflagration and detonation safety flame speed was derived by evaluating large amounts of experimental data.This appears to be a convenient and effective approach for the design and the selection of crimped-ribbon flame arresters.