The Experimental And Simulation Study Of Human Walking Induced Particle Resuspension Indoor Environment

With the increase of the time of human activities in indoor environment,city residents spent about 90% of their time in indoor environment.So,the quality of indoor environment is got more and more attention from people.Suspended particle in the air is the main factor that affects the quality of indoor air.For example,the smog which has a major impact on our lives and works is mainly due to the excessive amount of inhalable particulate matter in the air.Suspended particles will hurt the human body and cause physical discomfort.There are many reasons for the suspension of these particles.The indoor human activity is the key factor that causes the suspension of particles and ordinary human walking will also cause the suspension of particles.Therefore,it is necessary to study the resuspension of indoor particles and improve indoor air quality.The main research of this subject is the human walking induced particles resuspension in indoor environment.This paper used the experimental study combined with the numerical simulation to study the resuspension of particles under different conditions which induced by human walking in the room.The main work and creative achievements of this paper are:1.The effects of different relative humidity on the resuspension of particles were studied.Under different relative humidity conditions(RH = 40%,50%,60%,70%,80%),the ground material is long-staple carpet and no ventilation.It studied the human walking induced by particle resuspension and measured the suspended concentration and particle density of different size of particles in the air.Besides,the variation of particulate matter with different particle size and the change rule of particles with the same particle size under different humidity were analyzed under the same humidity.It was found that in the case of high relative humidity,the small size of particles condensed into large size of particles,while in the case of low relative humidity,the suspended matter concentration and particle density of particles with small particle size were relatively high.2.The effects of different speed of wind on the resuspension of particles induced by human walking were studied.In the absence of ventilation and existence of ventilation(low wind,stroke,high wind),relative humidity RH = 50%,ground material is long-staple carpet,study the effect of human walking on particulate matter of secondary suspension and compared the concentration of particles which suspended in the air and the changing rule of the particle density in these cases.It was found that the suspended matter and the suspension density of the particles were larger than those without the wind in the case of ventilation.In addition,with the increase of wind speed,the suspended matter and the density of particulate matter of small size of particles will increase,while the suspended matter concentration of large particles will be reduced to different degrees.3.The numerical simulation is used to study the movement law of particulate matter.On the basis of experiment combined with numerical simulation,to understand the motion path of particles under the condition of ventilation.It can get a more complete understanding of flow of air around the foot when walking and explain the suspended particles more clearly.It is found that the secondary suspension of the particles is mainly due to the local high speed area produced by the human body walking or ventilation.This local high speed area will cause the secondary suspension of particles and the particles will move with the changes of speed field.