Effects Of Rigid Disturbance On Propagation Of Flammable Gas Detonation In Pipeline

Combustible gas explosions seriously threaten industrial production and life safety.The flammable gas leaks and is detonated in a confined space,which is highly likely to cause detonation and destroy equipment and cause casualties.Existing studies have shown that obstacles have a significant impact on the development,spread and failure of detonation.However,the obstacles with the blockage rate as the main research parameter as the representative of the influence on the detonation propagation and failure in the pipeline have not been systematically studied and understood.In-depth study of this law has important guiding significance for disaster prevention and practical application of detonation waves.Based on this,the rigid spiral and orifice obstacles are used as disturbances to quantitatively study the explosion propagation characteristics of flammable gas after rigid disturbance.The main work and conclusions are as follows:?1?Explosion propagation experimental device was designed and built.Self-made high-sensitivity photoelectric sensor and 16-channel high-frequency synchronous acquisition ensure experimental measurement accuracy The device can realize rigid spiral disturbance to accelerate the formation of detonation waves and the propagation of the detonation wave by the rigid orifice plate.?2?By changing the initial pressurre,the propagation of different fuel gas flames without disturbance is experimentally studied.The results show that the methane-air flame always propagates in the form of deflagration;the ethylene-air changes with the initial pressure and finally forms two types of deflagration and detonation?DDT?.The way to stimulate detonation is DDT;The distance of DDT of acetylene-air is affected by the initial pressure and gradually increases as the initial pressure decreases.?3?The experiment has been completed the propagation law of flame with spiral obstacle as the source of rigid disturbance and compare it with the undisturbed condition.The spiral disturbance accelerates the propagation of methane-air mixture,but still cannot form detonation wave.Compared with the DDT distance of 4100mm without disturbance,The distance of DDT of ethylene-air mixture is shortened to less than 1900mm under the rigid spiral disturbance of Br=0.520,D=104mm and 780mm?L₀?1680mm.Compared with the DDT distance of 3115mm without disturbance,The distance of DDT of acetylene-air mixture is shortened to less than1900mm under the rigid spiral disturbance.?4?The influence of the position of the rigid disturbance and the degree of disturbance on the detonation wave is experimentally studied by changing the location?L₁=2600mm?3600mm?4600mm?and blocking ratios?Br=0.41⁰.99?of orifice plate.It is found that both the disturbance distance L₂ and L₃ are negatively correlated with the orifice plate location L₁after the detonation wave passing through the orifice plate.Conversely,L₂ and L₃ are positively correlated with the blocking ratios.In the range of the blocking ratios of 0.55?Br?0.99,the range of disturbance distance L₂ and L₃ is respectively 1357mm?L₂?3150mm?638mm?L₃?2000mm.In addition,the minimum velocity that being disturbed is negatively correlated with blocking probability,and the minimum velocity is varied from 0.11V_CJ to 0.52V_CJ.