Study On Adding Vortex Generators At Different Included Angles And Water Vapor Strengthening To Promote Particle Growth In Turbulent Agglomeration Chamber

Air pollutants do great harm to human health,among which particulate matter is highly valued by people because it can cause haze and damage human respiratory and blood circulation system.At present,there are many technical means to control particulate matter emission,but the control effect of traditional dust removal equipment is limited,and the transformation of composite dust removal technology is complicated,and the cost is high,so it is difficult to popularize and apply on a large scale.In order to improve the removal efficiency of particulate matter,pretreatment of particulate matter can be carried out before using dust removal equipment to increase particle size and reduce the removal difficulty.Among various pretreatment methods,turbulent agglomeration and heterogeneous condensation have been widely studied because of their good effect and easy application.At present,most studies on turbulent agglomeration adopt numerical simulation method,and improve the particle agglomeration effect by changing the geometry and arrangement Settings of vortex generators in the agglomeration chamber.However,there are few relevant experimental studies,and as the included angle of vortex generator is a parameter widely studied in other fields,there is a lack of research in the field of particulate matter removal,and there are also few studies on the pretreatment of particulate matter by the combination of turbulent agglomeration and heterogeneous condensation,which need to be further studied.Therefore,this paper adopts the method of combining experimental measurement and numerical simulation to study the effect of changing the included angle of"V"vortex generator on particle turbulence agglomeration and the effect of water vapor enhancement on particle growth.The main contents are as follows:In order to explore the influence of vortex generators with different included angles on the turbulent agglomeration effect of particles,in the first part,the characteristic data of the flow field in the agglomeration chamber were measured with the Particle Image Velocimeter(PIV),the particle size and concentration change data were measured with the Phase Doppler Particle Analyzer(PDPA),and the flow field and particle behavior data obtained by numerical simulation were combined.The mechanism of the effect of vortex generator’s included angle on particle size growth was investigated.The results show that:(1)when the included angle of vortex generator is 160°,the particle size increases best,the average particle size increases from 6.13μm to 10.44μm,and the particle concentration decreases from 4.6×10~3/cm~3 to 1.6×10~3/cm~3.(2)When the included angle of the vortex generator increases,the low speed zone and negative pressure range at the rear of the vortex generator increase,and the intensity of reflux increases.(3)If the included angle of the vortex generator increases,the particles are squeezed by the vortex,the local enrichment effect is more obvious,and the average relative velocity between particles is increased,which reflects that the crossing of particle motion paths is more intense,which is conducive to the collision agglomeration between particles.In order to further obtain better growth effect of particulate matter,the second part sets up supersaturated water vapor environment in the agglomeration room,adopts the numerical simulation research method,combines turbulent agglomeration with heterogeneous condensation,explores the effect of water vapor on enhancing the growth of particulate matter,and tries to analyze the effect of vortex generator on promoting particle growth from the perspective of energy consumption.The results showed that:(1)the higher the relative humidity of water vapor in the flow field,the more water vapor available for heterogeneous condensation,the more conducive to the growth of particulate matter.When the relative humidity at the inlet was 130%,the average particle size at the outlet increased from 2μm to 6.183μm.(2)Changing the included angle of vortex generator has little change in the relative humidity distribution in the flow field,but has a great effect on the residence time of particles.If the included angle increases,the average residence time of particles is longer,the growth time of particles in the flow field is longer,and the growth range of particle size is larger.(3)The increase of included angle will not only improve the particle growth effect,but also increase the energy consumption,among which the energy consumption increases the most when the included angle increases from 130° to 160°.