| As an international problem in the fields of energy,metallurgy and chemical industry,high temperature dust removal has attracted more and more attention due to its broad application prospect.So far,there are many high temperature dust removal technologies studied in the world,all of which have their own advantages and characteristics.Among them,the electrostatic dedusting technology based on cathode discharge with low escape work is considered to have a promising future and is worth further exploration.In this paper,the author takes the linear rare earth tungsten cathode high temperature electrostatic precipitator as the research object,obtains the dust particle migration and trapping characteristics in the electrostatic precipitator through numerical simulation,and systematically analyzes the influence of various factors on the dust fractional dust removal efficiency.Firstly,the mathematical models for calculating the charge,electric field distribution and electric field force of dust particles were established by using the theories of cathode electronics and electrostatic force.A mathematical model of gas flow,particle migration and collision under multi-field coupling in a dust collector is established by using CFD-DSMC method and gas-solid two-phase flow theory.Then,with the help of FLUENT software and Visual Studio algorithm,the established complex mathematical model is numerically calculated,and the particle movement trajectory in the esp under different conditions is intuitively displayed through Visual Basic.Through numerical simulation,the influence of different working conditions on dust migration characteristics and capture efficiency is analyzed and discussed,and the following conclusions are drawn :(1)under the condition of zero electric field,particle size has little influence on particle movement characteristics through the comparison of particle migration trajectory under different working conditions;At the same particle flow rate,increasing the velocity and decreasing the particle density can weaken the particle aggregation tendency.The velocity of particle migration from the center to the wall decreases gradually in the radial direction,but all of them show an upward trend.With the same flow velocity at the inlet,within a certain range of particle number concentration,the time experienced by particles from the inlet to the outlet is not different,but the larger the particle number density is,the more obvious the particle aggregation tendency is in the axial direction.Based on the calculation and analysis of the particle collection efficiency under different working conditions,it is found that when there is no applied electric field,the collection efficiency of the esp increases with the increase of particle size,decreases with the increase of inlet airflow velocity,increases with the increase of the length of the precipitator and increases with the increase of the number of particles,Increases with the increase of operating temperature.(2)based on the numerical simulation calculation of the accumulative collection efficiency of the electrostatic precipitator under different working conditions,when the working voltage is 2000 V,the temperature is 1073 K,and the inlet airflow velocity is 1.5m/s,the collection efficiency of the precipitator for particles of 1 ?m is only 51.35%,and that for particles of 10 ?m can reach 100%.For particles of 5 ?m,when the inlet airflow velocity increases from 1.0m/s to 2.0m/s,the collection efficiency of the esp decreases from 100% to 42%.The collecting efficiency of the electrostatic precipitator is significantly affected by the working voltage.When the operating voltage is3000 V,particles with particle size greater than 5 m have been all collected before reaching the outlet of the precipitator.The length of the dust collector has a great influence on the dust removal efficiency.When the length increases from 465 mm to 665 mm,the dust removal efficiency increases from 42.5% to 86.05%,The working temperature has little influence on the collecting efficiency of the precipitator.When the working temperature increases from 1073 K to 1373 K and the working voltage is 2000 V,the collecting efficiency increases from 75.75% to 89%.(3)by comparing the dust migration trajectory and the collecting efficiency of the precipitator under the zero electric field and the applied electric field,it is found that improving the intensity of the applied electric field is the key to improving the dust collecting characteristics of the precipitator,especially the efficient collecting efficiency of fine particles.Based on the numerical simulation results,it is found that the dust removal efficiency increases with the increase of voltage,and the higher the voltage is,the more obvious the change trend is. |
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