本文選題：PM2.5 + 擴散��； 參考：《長安大學》2015年碩士論文

【摘要】：PM2.5是我國區(qū)域性灰霾天氣的重要成因之一,且PM2.5因其粒徑小、質量輕、重力小、比表面積大、活性強等特點對人體健康、城市空氣質量和能見度影響顯著。不同地區(qū)的PM2.5源解析研究成果一致認為機動車排放是PM2.5的重要來源之一,所以了解汽車尾氣PM2.5的排放擴散特性顯得尤為重要。論文采用實驗與仿真模型相結合的方法,研究單車尾氣PM2.5排放擴散特性。在了解計算流體力學基本理論的基礎上進行了車載尾氣采集實驗,實驗以添加95#汽油的東風悅達起亞k2汽車為研究對象,以SEMTECH-EFM3車載尾氣流量計、TSI8530粉塵監(jiān)測儀、干燥管和電腦等為實驗工具進行路試直接采樣。實驗分別采集了怠速、一檔10km/h、20km/h、二檔20km/h、30km/h、40km/h和三檔20km/h、30km/h、40km/h、50km/h下的尾氣流量、尾氣密度和PM2.5濃度。根據(jù)實驗得到的數(shù)據(jù),經過計算得到尾氣排放速度。然后運用CFD軟件FLUENT的專用前處理器GAMBIT對汽車排放的物理模型進行簡化,建立相應的幾何模型并劃分網格。接著運用求解器FLUENT進行求解計算。最后對實驗結果進行后處理和分析。論文得到如下結論:同一檔位下,PM2.5濃度隨車速的增大而升高;怠速條件下尾氣排放速度最低,但其PM2.5排放濃度略高于一檔10km/h和20km/h條件下的值;尾氣排放速度對PM2.5擴散有重要影響:同一檔位下,隨車速的增大,尾氣排放速度增大,其擴散范圍增大;同一車速下,隨檔位提高,不利于PM2.5的擴散,容易造成PM2.5積聚;尾氣排放方向對PM2.5擴散也有一定影響:與水平方向排放相比,向下傾斜的尾氣排放方向有利于PM2.5的沉降,而向上傾斜的尾氣排放方向會造成PM2.5長時間的懸浮。
[Abstract]:PM2.5 is one of the important causes of regional haze weather in China, and PM2.5 has a significant effect on human health, urban air quality and visibility because of its small particle size, light weight, small gravity, large specific surface area and strong activity. The results of PM2.5 source analysis in different regions agree that motor vehicle emissions are one of the important sources of PM2.5, so it is very important to understand the diffusion characteristics of vehicle exhaust PM2.5. In this paper, the diffusion characteristics of PM2.5 emissions from bicycle exhaust are studied by combining experimental and simulation models. On the basis of understanding the basic theory of computational fluid mechanics, the vehicle tail gas collection experiment was carried out. The experiment took Dongfeng Yueda K2 vehicle with 9 gasoline as the research object, and took the SEMTECH-EFM3 vehicle exhaust gas Flowmeter TSI8530 dust monitor as the research object. The dry tube and computer were used for direct sampling of road test. The experiment collected the tail gas flow, tail gas density and PM2.5 concentration at idle speed, 10 km / h, 20 km / h, 30 km / h, 40 km / h and 30 km / h / h, respectively, at 30 km / h / h and 30 km / h / h, respectively. According to the experimental data, the exhaust emission rate is calculated. Then the physical model of vehicle emissions is simplified by using GAMBIT, a special preprocessor of CFD software FLUENT, and the corresponding geometric model is established and meshed. Then the solver FLUENT is used to solve the problem. Finally, the experimental results are processed and analyzed. The conclusions are as follows: the concentration of PM2.5 in the same gear increases with the increase of vehicle speed, the exhaust emission rate is the lowest under idle condition, but the PM2.5 emission concentration is slightly higher than that under the first 10km/h and 20km/h conditions. The emission rate of tail gas has an important effect on the diffusion of PM2.5: under the same gear, the speed of exhaust gas emission increases with the increase of the speed of vehicle, and the diffusion range of the tail gas increases with the increase of the speed of the vehicle, and the increase of the speed of exhaust gas with the speed of the same speed is not conducive to the diffusion of PM2.5, and it is easy to cause the accumulation of PM2.5. The direction of tail gas emission has a certain effect on the diffusion of PM2.5: compared with horizontal emission, the downward inclined direction of tail gas emission is conducive to the settlement of PM2.5, while the upward direction of tail gas emission will cause the PM2.5 to suspend for a long time.
【學位授予單位】：長安大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：X513;X734.2

【參考文獻】

相關碩士學位論文 前1條

1 張強;機動車尾氣擴散流動CFD數(shù)值模擬[D];南京理工大學;2007年

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本文編號：1834376