Experimental Study And Simulation Of Charged Particles Coagulation In High Frequency Alternating Electric Field

Fine particle pollution has become a very serious environmental pollution problem,and increasingly attracted national attention.Because of the removal effect of fine particles by conventional dust removal device is not ideal,so a variety of coagulation technology came into being.Among them,the coagulation technology of charged fine particles in alternating electric field has received wide attention from scientists all over the world.Early alternating electric field coagulation mostly uses low-frequency AC.It is not mature to study the electrical coagulation of charged fine particles in high frequency alternating electric field,and few experimental studies have been done.Through the industrial application of Indigo electric coagulation and Cosa/Tron electric coagulation,compared with low frequency electric coagulation,high frequency alternating electric coagulation is not only low energy consumption,but also superior in coagulation effect.In view of this,this paper carried out the high frequency alternating electric field of charged particles coagulation experimental and theoretical analysis.The mechanism of high frequency alternating electric field charging fine particles coagulation is analyzed from two aspects: Study on the charging mechanism in DC electric field and study on the mechanism of alternating electric field of charged particles coagulation.The charge mechanism in DC electric field is divided into field charge and diffusion charge.The charge mode of the fine particles in the DC electric field is mainly the field charge.The core mechanism of the coagulation of alternating electric field of charged fine particles is determined electric coagulation coefficient.Using the coagulation mechanism of high frequency alternating electric field of charged particles,the coagulation coefficient Kg of charged fine particles in high frequency alternating electric field is deduced.A high frequency AC electric field coagulation experimental platform is built.The effects of charge voltage,high frequency AC power properties and aerosol properties on the coagulation efficiency were studied experimentally.Experimental results showed that: the results of the fine particles in the air are used as the source of the particles to do the experiment of electric coagulation in high frequency AC electric field are obvious.The maximum coagulation efficiency of fine particles of 0.3?m,0.5?m and 1.0?m diameter can reach 65%,62% and 55% respectively.The saturation charge qmax of aerosol particles cannot increase with the increase of the charge voltage.When the charge voltage reaches the upper limit voltage,the saturation charge of aerosol particles is no longer increasing.It can make the electric coagulation efficiency of fine particles increased to increase the charge voltage.And when the charging voltage is U1 > 15 kV,the charge quantity to be saturated,the electric coagulation efficiency tends to be gentle.At the same charge voltage condition,with the increase of pollution,the total coagulation efficiency decreased.The AC voltage has little effect on the electric aggregation of fine particles.The main factor affecting of high-frequency AC coagulation is power frequency,it can increase electric coagulation efficiency of fine particles when increase the frequency.When the average flow velocity in the rectangular channel increases,the electric coagulation efficiency reduce.With the increase of aerosol humidity,the coagulation efficiency of fine particles with different particle size decreased.And the influence of relative humidity on the small size of fine particle is more than the large size of fine particles.The agglomeration efficiency of fine particles formed by burning incense is consistent with that of air fine particles.However,the agglomeration efficiency of fine particles formed by burning incense at the same charge voltage is obviously lower than that of air fine particles.The discrete phase model(DPM)and population balance model(PBM)of FLUENT are used in the numerical simulation of trajectory and coagulation effect of fine particles in high frequency alternating electric field,and the simulation results are analyzed.It presents a method of coupling CFD with PBM to simulate the coagulation effect of particles.By comparing the simulated value with the experimental value,verify the correctness of the coagulation coefficients Kg of high frequency alternating electric field of charged particles.