Experimental And Numerical Study On The Performance Of Hybrid Electrostatic Air Filtration System

Corona discharge is an efficient method to improve the filtration efficiency of fibrous air filter.Once the corona discharge and filter medium is coupled,the filter efficiency could be enhanced without adding more pressure drop.This study developed two hybrid electrostatic air filtration systems.The experimental platform was established to investigate filtration system performance,including efficiency,pressure loss and energy consumption.This study also developed theoretical and numerical models to predict the practical performance of hybrid electrostatic air filtration systems.The numerical model is a powerful tool for engineering design.The innovation points of this research can be concluded as:(1)This study developed two hybrid electrostatic air filtration systems.The first one was pin to filter medium to grounded mesh system.The second one was hybrid system combining electrostatic precipitator(ESP)and fibrous filter in series.The corona discharge could charge the particles and increase filter efficiency obviously.The ozone generation was very small,although using corona technology.In the experimental results,the highest ozone generation was relative low,which met design criteria.The quality factor of hybrid electrostatic air filtration system was higher than the traditional middle or high efficient fibrous filter if the efficiency was similar.This study also developed theoretical model to predict the filtration efficiency of hybrid electrostatic air filtration systems.The predicted and measured results agreed reasonably.(2)This study utilized experimental method to investigate the electrostatic characteristics of pin to filter medium to grounded plate system.In the corona discharge field,the filter medium was placed on plate surface,influencing the voltage-current characteristics significantly.In pin to filter medium to grounded plate system,the presence of filter medium could increase electric resistance and reduce current value.However,the partial discharge existed in filter medium(so called ‘back corona effect')and increased the total current value.Based on back corona discharge theory,this study developed a theoretical model to predict the voltage-current relationship in pin to filter medium to grounded plate system.The predicted and measured results agreed reasonably.(3)This study developed a hybrid numerical model to simulate the multiple physics processes in hybrid electrostatic filtration system,including corona discharge,air flow and particle motion.Particles were charged in ionized electric field.The air drag force and electrostatic force would act on charged particles and moved them to air filter.This study simulated the filtration efficiency of hybrid electrostatic filtration system using plat filter medium.The modeled and measured efficiency results agreed well.Based on the validated numerical model,this study investigated the corona assisted pleated filter.The influence of system parameters on filtration efficiency was considered,such as pleat structure,applied voltage.The numerical method could be used in engineering application.