The Study On Characteristics Of Particle Suspension And Transport In Indoor Environment

Along with the deepening of global warming,the use of fossil fuels and desertification has brought great threat to human living conditions,with the development of the domestic economy in recent years,automobile exhaust and other causes of air pollution,domestic automobile,energy conservation and environmental protection policy of continuously introduce,soaring sales of air purifier can see more and more high to the requirement of indoor air quality.Now living in the number of respiratory disease caused by the smog has increased dramatically,fog affects the vast majority of people in the city's health,in real life,most people in an indoor activity time is about nine over ten of the total time,indoor particulate matter suspended and transport for indoor air quality has important influence,to People's Daily life and good health have great influence.The key factor that causes the secondary suspension of particles in indoor deposition is indoor human activities.Indoor human walking is one of the most common forms of exercise,and it is of great significance to improve indoor living environment by studying the related mechanism of particulate suspension and transport caused by human behavior.In this paper,the characteristics of particulate matter suspension and transport in indoor environment are studied.In this paper,the changes of suspended particulates in the air are studied under different working conditions and in different working conditions.The main work and creative achievements of this paper include:1.With no ventilation in the research room,and the effect of human walking on indoor particulate matter was suspended under different ground materials and different relative humidity.On the surface of the material(long-haired carpet,undercoat carpet,wooden floor),different relative humidity(RH = 40%,60%,80%)cases,human walking on particles in suspension and the influence of transport,measurement of different diameter particles suspended in air concentration and particle density,particle analysis under different ground material is the same humidity floating condition and the same ground material particles under different humidity conditions.The results show that the humidity has a great influence on the small particles.As the humidity increases,the particle size of small particles is coagulated and the particle size of small particles decreases.Compared with carpet,wood floor is not easy to cause secondary suspension of particulate matter,which is more conducive to human health.2.To study the effect of footfall and falling walking on particle suspension and transport in small space.In relative humidity RH = 50%,ground material is undercoat carpet,study different lift height(0.06 m,0.12 m,0.06 m)and speed(0.05 m/s,0.1 m/s,0.15 m/s)of particulate matter secondary suspension and the influence of the transport,compared to more than nine cases,the concentration of particles suspended in the air and the changing rule of the particle density.The results show that: PM1,PM2.5,PM5 settlement speed is relatively fast,and the settlement trend is consistent with each step up and down,and the settlement rate of PM10 is slow.The higher the movement height,the slower the settlement speed.At the same time,PM2.5,PM5 sedimentation rate is relatively fast,and the settlement trend is consistent with the movement height of each step.PM1,PM10 is slow to settle.The higher the movement height,the slower the settlement speed.3.The related numerical simulation was carried out for the movement of footstep in the small space,and further explored the influence of the footwork on the particles in the surrounding air.The results show that with the pace of movement at the bottom of the foot can produce secondary suspended particulate matter,the foot at the front and rear will produce vortex,as the growth of the movement time,particulate matter in eddy current,under the action of gravity field factors such as comprehensive,eddy diffusion occur around the footsteps,along with the happening of the vortex in the flow field,growth and annihilation process.At the same time,the secondary suspension trajectories of indoor particles were studied by numerical simulation.The results show that the air conditioning scavenging air will produce more vortexes in the room,and the vortexes on the ground are the largest,and these vortexes will increase the secondary suspension of particles on the ground.By studying the effect of air conditioning sweep on secondary suspension,combined with the working condition of human in the indoor,it can be improved scientifically in the position of air conditioning outlet.