Numerical Simulation Study Of Electrostatic Welding Fume Dust Collector

With the development of the times,welding technology is widely used in industrial production and manufacturing processes.However,the welding fumes generated during welding operations can be hazardous to the health of workers and cause environmental pollution.Therefore,welding fumes need to be collected and purified.As an efficient,clean and energy-saving fume and dust treatment device,electrostatic precipitators are used in coalfired power plants,cement plants,indoor purification and many other fields.However,there are few studies on electrostatic precipitator to treat welding fume,and most of the researchers treat the treated fume as a single component during numerical simulation.Based on previous experimental results,it is known that the physicochemical properties of the fume and dust affect the collection efficiency.In order to improve the research related to the electrostatic precipitator treatment of welding fume,to find the factors affecting the performance of the precipitator,and to obtain methods to improve the collection efficiency,this thesis conducts a numerical simulation study of welding fume in the electrostatic precipitator.The factors and laws affecting the collection efficiency are summarized,and the mechanism of the collection efficiency is clarified in terms of the synergistic field and particle charging and movement.First,physical and mathematical models were established and the reliability of the models is verified by experimental results from the references.Mathematical models of electric field,flow field,particle charge and motion in the electrostatic precipitation process were constructed.The control equations of the electric field were translated into the programming language,and the physical fields are coupled through a User-Defined Function(UDF)module.Using macros to incorporate the physical parameters of each component of the welding fume into the calculation.The accuracy of the physical and mathematical models and the correctness of the user-defined program were verified in terms of both potential distribution and collection efficiency based on the experimental data of Penny et al.and Kim et al.Then,a simulation study of a wire-plate electrostatic precipitator for the treatment of welding fume was carried out.The distribution characteristics of the flow field and electric field as well as the welding fume particle charge and motion are obtained.The flow field in the electrostatic precipitator is an electrohydrodynamic secondary flow under the combined effect of flow field and electric field.The particles move in the electrohydrodynamic secondary flow in a step-like trajectory,with a step towards the collection electrode at the corresponding position of the corona electrode.The particle charge is related to the particle diameter and the welding fume component.The electrostatic precipitator is more sensitive to the welding fume component at low flow velocity or high voltage,and the difference in the collection efficiency of each component is more pronounced.Subsequently,the calculated results were compared for different corona electrode forms,corona electrode deflection angles,corona electrode spacing,and corona electrode sizes.It is found that the electric field strength decreases the fastest near the triangle corona electrode.The ion charge density increases with the decrease of the number of sides of polygonal corona electrodes.The shielding effect weakened with increasing corona electrode spacing.The corona electrode variation enhances the electric field characteristics,which is the main reason for the increased collection efficiency.Finally,the removal of welding fume in the electrostatic precipitator with a C-type collecting electrode was studied.Compared with the flat collection electrode,the C-type collection electrode reduces the flow velocity of welding fume near the collection electrode and increases the electric field strength between the corona electrodes.At higher flow velocity,the C-type collection electrode is more advantageous to improve the collection efficiency.In this thesis,the simulation of electrostatic precipitator to remove welding fume is carried out,and the factors and laws affecting the collection efficiency are summarized and the influence mechanism is clarified.It provides a meaningful reference for optimizing the electrode configuration and improving the welding fume collection efficiency.