Study On Couping Mechanism Of Flame Waves And Shork Waves Of Combustible Gas Explosion In Complex Structure Pipeline

In this paper,methane,which is a representative combustible gas,is used to improve the square flammable gas explosion experimental pipeline.Of mesh obstacles,changing the shape and diameter of the pipe itself,making its internal structure complicated Establish a model consistent with the experimental pipeline for simulation.Comparing the simulation results with the actual experimental data,the flame wave and shock wave changes in flame propagation are studied in depth,and more comprehensive experimental results are obtained.The barrier with holes has a certain degree of excitation effect on the propagation of flame and shock waves.Increasing the blocking rate of the barrier partition will cause the pressure difference between the front and back of the barrier to become larger and the flame propagation speed to decrease.In the case of the same blocking rate,the relationship between the maximum overpressure and the shape of the opening of the barrier partition is P triangle> P square> P circle> P no-load pipeline.The relationship between the maximum flame propagation speed and the shape of the opening of the barrier partition is v triangle> v square> v circle> v no-load pipeline.Mesh obstacles have a certain degree of excitation for the propagation of flame waves and shock waves.The flame propagation speed is faster than the unloaded pipeline at the initial stage of the explosion.When the flame approaches the mesh obstacle,the flame propagation speed decreases rapidly.After passing through the mesh obstacle,the flame speed increases and the overpressure rises to the peak.When the flame wave passes through the mesh obstacle with an aperture of 0.8mm,it will extinguish and produce a secondary explosion,so that the flame burning speed willquickly rise to the peak.Flame waves and shock waves will be excited when passing through the expansion and contraction sections of the reducing pipe.In the expansion section of the pipeline,the pressure rises rapidly,and the flame change conforms to the principles of hydrodynamics;the maximum pressure is reached when the explosion and overpressure pipeline shrinks;at the end of the pipeline,the pressure accumulated in the contraction section and the reflection wave generated by the reflection effect of the blind plate overlap each other Causes a slight increase in pressure.Use Fluent simulation software to simulate the changes of flame and shock waves during the propagation of an explosion in an empty pipeline.It is found that the pressure changes measured at different monitoring points in the empty pipeline are basically the same.The dynamic pressure generated by the explosion is compared with the static pressure.It seems very small,the explosion pressure is mainly static pressure.Simulation experiments were carried out on the pipeline with obstacles,and it was found that the parameters of the flame before it propagated to the obstacle were basically unchanged.When the flame propagated to the obstacle,the flame propagation speed became faster,and the shock pressure value suddenly increased near the obstacle.,The entire explosion process becomes faster.A simulation experiment was carried out on the variable-diameter pipeline,and it was found that the difference between the flame propagation process change in the variable-diameter pipeline and the no-load pipeline was mainly reflected in the expansion section and the contraction section of the pipeline.When the flame passes through the expansion section of the pipeline,the turbulence of the flame increases,the combustion surface of the flame is significantly deformed,and the flame's axial propagation speed will be faster than the radial propagation speed,and the flame thickness increases;when the flame spreads to the contraction section of the pipeline,the pressure Accumulation occurs,causing the flame to compress,deform,and fold,and the flame thickness decreases significantly.