本文關(guān)鍵詞： 街道峽谷 軌道交通施工 顆粒物PM_(10) 流體力學(xué)CFD 高度比 風(fēng)向污染源位置　出處：《武漢大學(xué)》2017年碩士論文　論文類型：學(xué)位論文

【摘要】：顆粒物引起的環(huán)境污染問題已成為全球共同關(guān)注的問題,城市房地產(chǎn)和基礎(chǔ)設(shè)施建設(shè)正如火如荼的進(jìn)行著,其建設(shè)施工產(chǎn)生的揚(yáng)塵對顆粒物貢獻(xiàn)較大,同時(shí),街道峽谷是較為常見的街道形式,由于其特殊的形態(tài)特性,顆粒物在其中更容易積累,從而出現(xiàn)嚴(yán)重顆粒物污染問題,并對周邊住宅區(qū)居民和街道峽谷內(nèi)行人健康產(chǎn)生危害,因此,研究街道峽谷內(nèi)的顆粒物分布情況具有重要的意義。本文選取湖北省武漢市洪山區(qū)光谷商圈中,正在建設(shè)的軌道交通2號線延長線某段街道峽谷為研究對象,顆粒物選取PM10,通過儀器實(shí)際測量和數(shù)值模擬對比分析,對影響顆粒物擴(kuò)散的街道峽谷高度比、風(fēng)向及污染源位置三個(gè)方面進(jìn)行具體的分析討論,為城市街道峽谷內(nèi)臨街建筑物布局及其顆粒物的防治措施提供理論依據(jù)。本文案例中街道峽谷可簡化為遞增型街道峽谷模型,網(wǎng)格劃分采用ICEM軟件,后處理運(yùn)用流體力學(xué)軟件FLUENT,采用TECPLT對圖形處理。街道峽谷內(nèi)的空氣流場選用標(biāo)準(zhǔn)K-ε模型,顆粒物運(yùn)動(dòng)選用離散相模型中的拉格朗日方法跟蹤顆粒物的軌跡,運(yùn)用有限體積法對所求的控制方程進(jìn)行離散。將儀器測量值與街道峽谷內(nèi)機(jī)動(dòng)車尾氣產(chǎn)生顆粒物加和,與本文數(shù)值模擬得到的顆粒物濃度值進(jìn)行對比檢驗(yàn),結(jié)果表明數(shù)值模擬的結(jié)果可靠性較好。將數(shù)值模擬得到的主要結(jié)論歸納如下:(1)污染源位于北側(cè)時(shí):西風(fēng)條件下,遞增型街谷的顆粒物主要聚集在峽谷中部,對稱型和遞減型街谷,顆粒物相對分散。遞增型街谷影響高度較均勻,約為20m。對稱型和遞減型街谷,從前端15m到尾端30m呈現(xiàn)平緩上升的趨勢。北風(fēng)下,街谷內(nèi)顆粒物濃度值較高區(qū)域均明顯增多,在街谷前后兩側(cè)和南側(cè)背風(fēng)區(qū)域的顆粒物影響范圍很廣泛,北側(cè)建筑物行人區(qū)域的顆粒物污染情況嚴(yán)重。南風(fēng)下,遞增型和對稱型街谷顆粒物分布規(guī)律一致,集中在街谷中部,南側(cè)較大間距可以適當(dāng)減緩顆粒物污染水平,且北側(cè)建筑物背風(fēng)區(qū)域的顆粒物濃度水平與間距處氣流溢出帶出顆粒物的能力相關(guān)。(2)針對顆粒物污染情況:街谷進(jìn)深方向時(shí),平行風(fēng)條件下街谷高度比對進(jìn)深方向顆粒物分布幾乎無影響;垂直風(fēng)條件下,遞減型和對稱型街谷在進(jìn)深方向的顆粒物分布規(guī)律相似,建筑物凹凸處和間距會(huì)改變顆粒物濃度水平。平行風(fēng)條件下,三類街谷在南北向的顆粒物濃度水平幾乎一致;北風(fēng)條件下,街谷南側(cè)到北側(cè)顆粒物濃度值逐漸升高,遞減型、對稱型和遞增型街谷濃度水平逐漸下降;南風(fēng)條件下,街道中間Y=0m處達(dá)到最高值,北側(cè)濃度水平較南側(cè)低。影響高度方面,不同高度比和風(fēng)向條件下,顆粒物在垂直高度的擴(kuò)散規(guī)律較相似,整體上呈現(xiàn)逐漸下降趨勢,其中5米以下隨垂直高度濃度下降最快,之后出現(xiàn)平穩(wěn)緩慢下降。(3)污染源為南側(cè)時(shí),對稱型街谷在三種風(fēng)向條件下,顆粒物污染情況均變嚴(yán)重,遞增型和遞減型街谷,顆粒物聚集位置發(fā)生微調(diào)。在街道峽谷內(nèi)人呼吸平面的顆粒物,北風(fēng)條件下遞減型街谷顆粒物污染最為嚴(yán)重,南風(fēng)時(shí)遞減型街谷顆粒物污染最輕。
[Abstract]:The problem of environmental pollution caused by particulate matter has become a global concern, the city real estate and infrastructure construction is carried out like a raging fire, the construction produces dust particles on the larger contribution, at the same time, the street canyon is the more common form of the street, due to its special morphological characteristics, particles more easily in the the accumulation, thus serious particulate pollution, and the surrounding residential area residents and pedestrian street canyon harm, therefore, has an important significance to study the distribution of particles in street canyon. This article selects the Hubei province Wuhan city Hongshan District Optics Valley District, is the construction of the Metro Line 2 extension line a section of a street canyon as the research object, selects the PM10 particles, through the instrument measurement and numerical simulation, influence of particle dispersion in street canyons high ratio, wind To the three aspects of pollution sources and the position of the specific analysis and discussion, and provide a theoretical basis for the city street canyon in the street the building layout and particulate control measures. In this case the street canyon can be simplified as increasing street canyon model, mesh by using ICEM software, postprocessing using CFD software FLUENT, using TECPLT graphics the air flow field in street canyon. The selection of standard K- turbulence model, particle motion using Lagrange method of discrete phase model of particle trajectory tracking, the control equations for the discretized using the finite volume method. The measurement value and the street canyon vehicle exhaust particles and values are compared to test in this paper, and numerical simulation of particle concentration, the results show that the numerical results of the numerical simulation is reliable. The main conclusions are summarized as follows : (1) the source is located in the north side: Westerly wind conditions, particles increasing mainly gathered in the street canyon Valley in central, symmetric and decreasing the street canyon, the particles are relatively scattered. Increasing the street canyon height is uniform, about 20m. symmetric and decreasing Street Valley, showing increased slowly. The trend from the front to the end of 15m 30m. The north wind, the particle concentration in the street canyon high region increased significantly, is widely used in street canyon before and after particles on both sides and on the south side of the leeward region influence scope, the particulate pollution on the north side of building pedestrian areas. Under the severe wind, increasing and symmetrical street canyon particles physical distribution, concentrated in the Central Valley of South Street, the larger distance can be appropriate to reduce particulate pollution levels, the particle concentration level and on the north side of building area and leeward spacing gas emanating out of the ability of particles. The particles (2) Pollution: Street Canyon depth direction, parallel valley wind conditions Xia Jie height ratio on the depth direction of the particle size distribution has almost no influence; vertical wind conditions, particle distribution decline and symmetrical street canyon in the depth direction of similar buildings, convex and concave and spacing will change the particle concentration level. Parallel wind conditions three types of street canyon in the north and south, the particle concentration level to almost the same; north wind conditions, on the south side of the street canyon to the north of the particle concentration increased gradually, decreasing type, symmetric type and incremental street canyon concentration level decreased gradually; wind conditions, the middle of the street at Y=0m reached the highest value, the concentration level is the south is low. Influence of height, different height ratio and wind conditions, particles are similar in the height of the vertical diffusion, showing the overall trend of gradual decline, of which 5 meters with the vertical height of the fastest decline in the concentration. After a steady decline slowly. (3) the pollution source for the south side, symmetrical street canyon in the three wind conditions, situation of particulates became serious, increasing and decreasing the street Valley, particle aggregation occurs in fine-tuning. Particles of street canyon people breathing plane, the condition of decreasing the street canyon particulate pollution is most serious, the decreasing street canyon particulate pollution is the lightest.

【學(xué)位授予單位】：武漢大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X513;X169

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