The Research Of Motion Regularity Of Granular Dust In The Ventilation Pipe

As we all know,industrial dust treatment need to choose a reasonable way and it will achieve better dust removing effect.At present,with a long pipe mechanical ventilation and dust removal measure is one of the effective measures of industrial dust control.the pipeline is bound to produce deposition phenomenon with the particle-dust in the pipeline for a long time to discharge.If any treatment measure isn't taken for the particles,it will lead to many adverse consequences,especially in the pipeline,severity ranging from dust accumulation to pipeline congestion?corrosion and so on.Before the dust removal,if the law of dust migration and sedimentation could be understood,it will be helpful to clear the dust and redesign the pipeline structure parameters according to the laws.This paper treats industrial dust pipeline as the study object,based on the theory of fluid mechanics ? jet theory and computational fluid dynamics,the physical and mathematical models were established for circular and square tube by Fluent6.3.26 simulation software,the standard k-e model and standard wall function was used to numerically analyze the flow field in the pipeline,the effect of wind speed?dust diameter and tube type on dust concentration distribution and deposition is simulated.The main study results are as follows:(1)The selection of the standard two-equation model can effectively simulate the distribution of the internal flow field of the two kinds of pipes.(2)The size distribution of pipe wall pressure is less affected by tube type and diameter of particle,much affected by wind speed.(3)After the length of pipe reaches a certain distance,the distribution of the velocity in the pipeline is not affected by the length of the pipe,when the pipe length is more than 25 m and the square pipe is more than 30 m,the flow velocity distribution in the pipeline is stable and the change is small.The greater the transmission wind speed,the greater the speed value?v to reach the maximum speed,but basically unchanged position to reach the maximum flow rate,the circular tube is 15 m,the square tube is 18 m.(4)Different size dust particle has a corresponding minimum deposition concentration transport wind speed with the transport progress,transport wind speed is too low,it is difficult to get the transport effect;transport wind speed is too high,it will increase energy consumption and the probability of collision between dust and the wall will increase;Therefore,when the ventilation wind speed is designed,the optimum transmission wind speedshould be selected for different size dust particle.(5)With the wind speed of 16 m/s and for the dust diameter size of 0.25 ?m to 2.5?m,the average dust deposition concentration value of the square tube on wall is lower than circular tube.When the particle diameter is 0.25 ?m,the average dust concentration value of the square tube wall is 0.05 g/m3 lower than the circular pipe;When the particle diameter is2.5 ?m,the average dust concentration value of the square tube wall is 0.15 g/m3 lower than the circular pipe;Therefore,when the dust particle that the diameter is 0.25 ?m to 2.5 ?m is transported by industrial pipe in the speed of 16 m/s,we could consider to apply the square tube to transport.