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Université de Jilin (2020)

Study on Dust Retention Characteristics of Vegetation Barriers and Bionic Design of Porous Fence

赵冬森;

Titre : Study on Dust Retention Characteristics of Vegetation Barriers and Bionic Design of Porous Fence

Auteur : 赵冬森;

Grade : Master’s Theses 2020

Université : Université de Jilin

Résumé
With the rapid development of economy,the pollution of particulate matters(PM)from open source becomes more and more serious.Escaped atmospheric particles can cause smog,waste of piled materials,negative effects on human health,and restrict economic development.One of the most effective management strategies to reduce particulate matter from open source is to set vegetation barrier or artificial porous barrier to block and intercept the particulate matter during the diffusion process.Vegetation barrier(VB)as a porous medium,can trap particles with different particle sizes in the canopy and adjust the porosity by swinging branches and leaves to adapt to wind changes.But the growth of vegetation is affected by water resources,soil and seasons.However,artificial porous barriers have no such limitations.Currently,commercial artificial porous barriers,including rigid and flexible windbreak fence,can reduce the dispersion of particles by reducing the wind speed.However,these commercial artificial fences are poor at trapping fine particles.In addition,there is a contradiction between the wind speed reduction and the wind load acting on the barrier.Moreover,the opening form of the hole on the porous barrier is fixed leading to fixed porosity of the fence.Therefore,it is of great significance to study the vegetation barrier as the bionic prototype to optimize the artificial porous barrier and improve the wind environment and retain fine particles from open sources.In this study,the typical tree species in northeast China were studied,including Padusvirginiana‘Canada Red’,Pinussylvestris var.mongolicaLitv.,Malusbaccata(L.)Borkh.andAcer buergerianumMiq.Powder particles were milled from the collected dust sources in a laying hen house to simulate the dispersion of PM from the laying hen house.The ability of different tree species blocking particles was investigated by establishing natural barriers and conducting tests on the four vegetation barriers.The effects of VBs on the attenuation efficiency of wind speed and PM concentration as well as the influcing factors,such as ambient temperature,relative humidity,and characteristics of vegetation leaves and barriersn,on particle blocking ability were analyzed.The macroscopic mechanism of vegetation barriers blocking and adsorbing particles was identified.The results showed that the simulation test of particle diffusion retardation designed in this study can be used,and the four kinds of vegetation barrier can effectively block fine particles.There were differences in the blocking efficiency of different vegetation barriers on particles,with the order of Padusvirginiana‘Canada Red’>Pinussylvestris var.mongolicaLitv.>Malusbaccata(L.)Borkh.>Acer buergerianumMiq..The blocking efficiency of Padusvirginiana‘Canada Red’on PM1,PM2.5 and PM10 was 73.80±15.61%,73.73±15.80%and67.35±19.55%,respectively.The order of attenuation efficiency of vegetation barriers to wind speed was Padusvirginiana‘Canada Red’>Acer buergerianumMiq.>Pinussylvestris var.mongolicaLitv.>Malusbaccata(L.)Borkh..The attenuation efficiency of Padusvirginiana‘Canada Red’to wind speed was 41.14±6.91%.The above two orders were not the same,indicating that the ability of the vegetation barrier to block particles was also affected by other factors

Mots clés : Vegetation barriers; porous barriers; wind tunnels; retardation efficiency;

Présentation (CNKI)

Page publiée le 25 octobre 2020