Research On The Influence Of Air Purifier Flow Structure On The Flow Field And PM_2.5 Purification Efficiency

In recent years,many provinces and cities in China have often been shrouded in smog.PM_2.5is the main component of smog and also the main source of air pollution.Due to the small particle size and large specific surface area,PM_2.5is prone to adsorb polycyclic aromatic hydrocarbons,polycyclic benzene,viruses,bacteria and other toxic substances on its surface,causing great harm to human health,global climate and ecosystem.Air purifier can reduce indoor PM_2.5concentration effectively and thus improve indoor air quality.The air purifier used in this experiment is based on the principle of physical adsorption.In order to reduce the flow resistance,tangential flow is adopted to purify the air.In other words,the adsorption material is parallel to the air flow direction.In order to increase the adsorption area and the collision probability between PM_2.5and the adsorption material,the adsorption material is in a pleated structure.In this paper,Fluent software was used to simulate the air pressure and velocity distribution in the flow channel of air purifier under different channel intervals and pleat depths.The simulation results show that the pressure decreases from the inlet to the outlet of the air purifier as expected,while localized low pressure low velocity zones exist in the pleated areas due to coupling induction and vortex.When the channel interval is less than or equal to the pleat depth,the velocity distribution inside the pleat is not uniform,while the channel interval is greater than the depth of pleat,it turns into a whirlpool shape.In order to explore the influence of the channel interval,pleat depth and air volume of the air purifier on the PM_2.5purification effect,PM_2.5concentration attenuation experiment was conducted in an airtight experimental chamber with reference to the national standard.The total attenuation curve,clean air delivery rate（CADR）,cleaning energy efficiency,effective purification efficiency and cumulative removal rate under different conditions were compared.The results show that CADR and cumulative removal rate reach their maximums when the channel interval,air volume and pleat depth of the flow channel are at their experimented high extremes.The cleaning energy efficiency reaches its maximum when the pleat depth and air volume are at their experimented low extremes with the channel interval remain at its the maximum.The effective purification efficiency reaches the maximum when the pleat depth and channel interval are at their minimums.Air volume has little effect on effective purification efficiency.Combined with the simulation and experimental results,CADR and the removal rate become high when a large vortex was formed in the pleat.When the pressure drop of flow channel is low,the cleaning energy efficiency gets high.