室內(nèi)超細(xì)微粒滲透?jìng)鬏敊C(jī)理研究
發(fā)布時(shí)間：2018-08-30 20:08
【摘要】：在室內(nèi)無明顯污染源的情況下,室外顆粒物的滲透是室內(nèi)顆粒物的主要來源。為了評(píng)估室內(nèi)人體污染物暴露風(fēng)險(xiǎn),有必要了解顆粒滲透過程的影響因素及傳輸機(jī)理。本文采用實(shí)驗(yàn)方法和數(shù)值模擬方法研究室外顆粒物通過建筑狹縫滲透進(jìn)入室內(nèi)的傳輸機(jī)理及其影響因素,并對(duì)狹縫內(nèi)污染物擴(kuò)散規(guī)律給予闡述。實(shí)驗(yàn)設(shè)計(jì)搭建不同尺寸狹縫的測(cè)量裝置平臺(tái),借助快速粒徑譜儀(FMPS)和質(zhì)量濃度采樣分析儀(DustTrak)測(cè)量?jī)蓪?shí)驗(yàn)艙內(nèi)的顆粒數(shù)濃度和質(zhì)量濃度變化,得到不同粒徑顆粒的穿透率和粒徑譜演變特征。研究顯示,在儀器粒徑測(cè)量范圍6～523nm內(nèi),隨著粒徑的增加,穿透率呈增加趨勢(shì),其主導(dǎo)影響因素為布朗擴(kuò)散運(yùn)動(dòng)。在狹縫壓差為4Pa,縫高為1mm,縫長(zhǎng)為43mm的情況下,平均穿透率變化范圍為0.51～0.98,而在縫長(zhǎng)為94mm時(shí),平均穿透率變化范圍在0.55～0.95之間,顆粒穿透率隨著縫長(zhǎng)增加和壓差減小而減小。室內(nèi)外顆粒數(shù)濃度呈線性相關(guān)性,其室內(nèi)外數(shù)濃度比值(I/O)為0.69～0.74,相關(guān)系數(shù)R2均大于0.99,表明室內(nèi)顆粒物濃度很大程度上與室外顆粒的滲透有關(guān)。室內(nèi)外顆粒質(zhì)量濃度平均比值為0.74,相關(guān)系數(shù)R2達(dá)0.98以上。室外顆粒PM1、PM2.5、PM10和總顆粒質(zhì)量濃度與穿透率呈負(fù)相關(guān)性。數(shù)值模擬方法采用Fluent軟件進(jìn)行計(jì)算,考慮其沉降機(jī)制如布朗擴(kuò)散、重力沉降以及Saffman升力的影響。數(shù)值模擬顯示,狹縫縫長(zhǎng)越長(zhǎng),壓差越小,縫高越小,顆粒穿透率就越小,其中縫高占主導(dǎo)影響因素。當(dāng)縫高變化時(shí),同一個(gè)粒徑的顆粒沉降到壁面的主導(dǎo)因素變化,穿透率也隨之變化。小粒徑顆粒布朗擴(kuò)散占主導(dǎo)作用,隨著粒徑的增大,重力沉降所占比率增加。在不同形狀管道中,粒徑較大的顆粒更容易沉積在入口段管道,因此入口段顆粒濃度最高。粒徑較小的顆粒隨氣流運(yùn)動(dòng)。通道拐角越多,顆粒沉積位置越分散,從而減小通道阻塞。L型管道和U型管道在拐角底部及管道右壁面顆粒濃度較高,由于拐角處存在漩渦,顆粒更容易沉積下來。
[Abstract]:The permeation of indoor particulate matter is the main source of indoor particulate matter without obvious indoor pollution sources. In order to evaluate the exposure risk of indoor human pollutants, it is necessary to understand the influencing factors and transport mechanism of particle permeation process. In this paper, experimental method and numerical simulation method are used to study the transport mechanism and influencing factors of indoor permeation of outdoor particulates through the building slit, and the diffusion law of pollutants in the slit is expounded. A platform for measuring slit with different sizes was designed and built. The change of particle number and mass concentration in the two experimental cabins was measured by (FMPS) and (DustTrak). The characteristics of penetration rate and particle size spectrum evolution of different particle size were obtained. The results show that the penetration rate increases with the increase of particle size in 6~523nm, and the dominant factor is Brownian diffusion movement. When the slit pressure difference is 4 Pa, the seam height is 1 mm, and the seam length is 43mm, the average penetration rate varies from 0.51g to 0.98, while when the slit length is 94mm, the average penetration rate ranges from 0.550.95 to 0.550.95. The particle penetration rate decreases with the increase of the slit length and the decrease of the pressure difference. The concentration of indoor and outdoor particles was linearly correlated with the ratio of indoor and outdoor particle concentration (I / O) was 0.69 ~ 0.74, and the correlation coefficient R ~ (2) was higher than 0.99, indicating that indoor particle concentration was related to the permeation of outdoor particles to a great extent. The average mass concentration ratio of indoor and outdoor particles is 0.74, and the correlation coefficient R ~ 2 is above 0.98. There was a negative correlation between outdoor particle PM1,PM2.5,PM10 and total particle mass concentration and penetration rate. The numerical simulation method is calculated by Fluent software, considering the influence of the settlement mechanism such as Brownian diffusion, gravity settlement and Saffman lift. Numerical simulation shows that the longer the slit is, the smaller the pressure difference is, the smaller the seam height is, and the smaller the particle penetration rate is, and the higher the slit height is, the more the influence factor is. When the seam height changes, the dominant factor of settling to the wall of the same particle size changes, and the penetration rate also changes. The Brownian diffusion of small particle size plays a dominant role, and the ratio of gravity deposition increases with the increase of particle size. In the pipeline with different shapes, the larger particle size is easier to deposit in the inlet pipe, so the particle concentration in the inlet section is the highest. The smaller particles move with the air flow. The more the channel corner, the more dispersed the particle deposition position, thus reducing the channel blocking. L-type pipeline and U-shaped pipeline in the corner bottom and the right wall of the pipe particle concentration is higher, because of the swirl around the corner, particles are easier to deposit down.
【學(xué)位授予單位】：中國(guó)計(jì)量學(xué)院
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X51
本文編號(hào)：2214154
[Abstract]:The permeation of indoor particulate matter is the main source of indoor particulate matter without obvious indoor pollution sources. In order to evaluate the exposure risk of indoor human pollutants, it is necessary to understand the influencing factors and transport mechanism of particle permeation process. In this paper, experimental method and numerical simulation method are used to study the transport mechanism and influencing factors of indoor permeation of outdoor particulates through the building slit, and the diffusion law of pollutants in the slit is expounded. A platform for measuring slit with different sizes was designed and built. The change of particle number and mass concentration in the two experimental cabins was measured by (FMPS) and (DustTrak). The characteristics of penetration rate and particle size spectrum evolution of different particle size were obtained. The results show that the penetration rate increases with the increase of particle size in 6~523nm, and the dominant factor is Brownian diffusion movement. When the slit pressure difference is 4 Pa, the seam height is 1 mm, and the seam length is 43mm, the average penetration rate varies from 0.51g to 0.98, while when the slit length is 94mm, the average penetration rate ranges from 0.550.95 to 0.550.95. The particle penetration rate decreases with the increase of the slit length and the decrease of the pressure difference. The concentration of indoor and outdoor particles was linearly correlated with the ratio of indoor and outdoor particle concentration (I / O) was 0.69 ~ 0.74, and the correlation coefficient R ~ (2) was higher than 0.99, indicating that indoor particle concentration was related to the permeation of outdoor particles to a great extent. The average mass concentration ratio of indoor and outdoor particles is 0.74, and the correlation coefficient R ~ 2 is above 0.98. There was a negative correlation between outdoor particle PM1,PM2.5,PM10 and total particle mass concentration and penetration rate. The numerical simulation method is calculated by Fluent software, considering the influence of the settlement mechanism such as Brownian diffusion, gravity settlement and Saffman lift. Numerical simulation shows that the longer the slit is, the smaller the pressure difference is, the smaller the seam height is, and the smaller the particle penetration rate is, and the higher the slit height is, the more the influence factor is. When the seam height changes, the dominant factor of settling to the wall of the same particle size changes, and the penetration rate also changes. The Brownian diffusion of small particle size plays a dominant role, and the ratio of gravity deposition increases with the increase of particle size. In the pipeline with different shapes, the larger particle size is easier to deposit in the inlet pipe, so the particle concentration in the inlet section is the highest. The smaller particles move with the air flow. The more the channel corner, the more dispersed the particle deposition position, thus reducing the channel blocking. L-type pipeline and U-shaped pipeline in the corner bottom and the right wall of the pipe particle concentration is higher, because of the swirl around the corner, particles are easier to deposit down.
【學(xué)位授予單位】：中國(guó)計(jì)量學(xué)院
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：X51
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