Study On Dynamic Distribution Of Particles In The Pipe Groove Under Gas-solid Two-phase Condition

The groove structure is a common structure that used in pipe transportation systems.When the medium to be transported was gas-solid mixture containing particles,the solid particles were extremely likely to accumulate in the pipe,thereby causing problems such as collision,wear and other problems.In order to reduce the accumulation,the industry often adopts a purging method to promote the fluidization of the particles inside the groove by blowing air inside the pipe,thereby achieving the purpose of eliminating particles.However,how the particles in the groove accumulate under the two-phase condition and how the fluidization characteristics of the particles inside the groove under horizontal ventilation have not been well solvedIn this paper,the gas-solid two-phase flow characteristics in the groove of the piping system were studied.We constructed a gas-solid two-phase transmission flow test platform and designed a visual groove structure.The high-speed camera was used to capture the accumulation process of particles at the grooves under the condition of the horizontal airflow state.The main research contents are as follows(1)The groove structure of the pipe was designed.The high-speed camera was used to observe the particle accumulation process at the groove part,and the CFD-DEM coupling method was used to simulate the particle accumulation process at the groove in the pipe.Quantitative analysis of the accumulated particles in the grooves was investigated by using the MATLAB program.The effects of airflow velocity,particle size,particle mass flow,baffle width and groove structure on particle packing were investigated.When the particles in the groove reach the stable stage,the inside of the deposited particles in the groove was stable.Under the experimental conditions of low gas flow rate and large particle size,the particles are more likely to accumulate in the grooves.On this basis,orthogonal experiments were carried out to investigate the influence of airflow velocity,particle size and particle mass flow on the particle accumulation in the groove.It is pointed out that the order of influence factors are particle size,particle mass flow,and gas flow velocity.(2)Experimental study on the fluidized motion of the accumulated particles in the groove under different gas flow rates,particle size and baffle structure.In the experiment,the particles of two colors were placed in layers above and below,left and right.The whole process of placing particles in the groove from stationary to leaving the groove under the action of airflow was obtained.By analyzing the flow process of particles,it was found that there was surging phenomenon in the process of fluidization of the accumulated particles in the groove.The length of the baffle and the inlet velocity were positively correlated with the occurrence of the surging phenomenon.The study also pointed out that the presence of the baffle reduces the time of particles flow out of the groove.The quantitative analysis of the residence time and number of particles in the baffled groove was carried out.