【摘要】：目前，隨著交通工具行駛速度和使用密度的不斷加大，行駛中發(fā)生火災事故也日趨增多。這類火災的火源點往往處于運動狀態(tài)且與空氣產(chǎn)生相對運動，從而形成移動火源。移動火源擴散燃燒火焰特征的研究是準確評估這類火災發(fā)展趨勢的基礎(chǔ)工作，對火災的預測、防范和救援具有實際應用價值和理論指導意義。同時該領(lǐng)域的研究有助于豐富和完善移動火源擴散火焰理論體系，對移動火焰燃燒的能源高效利用等方面具有指導意義。但目前國內(nèi)外學者對移動火源擴散火焰的基礎(chǔ)研究較少，至今仍未很清楚了解移動火源擴散火焰的內(nèi)在本質(zhì)和物理規(guī)律。本文通過移動火源擴散火焰在無限大空間圓周運動的實驗獲得火焰圖像，從火焰力場和熱量的角度分析了火焰圖像平均灰度、火焰面積、火焰傾角與火焰線速度、火焰距離轉(zhuǎn)軸半徑之間的關(guān)系，以揭示移動火焰擴散火焰的燃燒機理和影響規(guī)律。 文中搭建了無限大空間圓周運動移動火源實驗臺，通過Lightning RDT高速攝像儀以及同步測量控制計算機獲得火焰照片，并在Matlab軟件下對火焰圖像進行預處理。通過研究表明，先用電視工業(yè)的標準灰度化處理圖片，后利用中值濾波法來消除噪聲干擾，再使用Canny算子檢測出火焰邊緣圖像，可以得到較好的圖像處理效果。 在圖像預處理的基礎(chǔ)上，對移動火源擴散火焰圖像特征進行提取和變化規(guī)律總結(jié)。實驗結(jié)果顯示，火焰在不同半徑位置時，火焰圖像平均灰度值隨火焰線速度的變化而先下降后上升，再大幅下降；火焰面積隨火焰線速度的變化呈現(xiàn)先增大后減小；隨著火焰線速度的增加，剛開始階段火焰傾角增大得很快，而到達某個臨界值之后增大的幅度變緩慢。究其原因認為，第一階段線速度不大時，氣流散熱大于生成熱量，火焰溫度略有下降，火焰圖像平均灰度值隨之稍微減少，氣流擾動增加加劇燃料與空氣的混合程度以及火焰溫度稍微下降導致火焰面積增大；第二階段火焰線速度一定程度時，生成熱量大于氣流散熱，，火焰溫度略有上升，火焰圖像平均灰度值隨之稍微增加；第三階段在移動火源運動速度達到較大時，氣流過大帶走燃料使燃燒量大幅減少，火焰溫度大幅下降，火焰圖像平均灰度值隨之也減少；第二和第三階段里燃料與空氣混合程度達到極限以及過大的氣流會帶走更多熱量和燃料導致火焰面積減少。而火焰傾角由于空氣阻力增大并起拉伸作用，開始時火焰傾角增大得很快，后到達臨界值后火焰面積減少抵消火焰線速度的影響，火焰傾角增大幅度相對平緩。以上的研究，實現(xiàn)了對移動火源運動下火焰特征提取與規(guī)律分析，為移動火源的機理研究提供了一定的實驗和理論基礎(chǔ)。
[Abstract]:At present, with the increase of vehicle speed and use density, fire accidents are also increasing. The fire source of this kind of fire is usually in the state of motion and is in relative motion with the air, thus forming the moving fire source. The study of the flame characteristics of moving fire source diffusion combustion is the basic work to accurately evaluate the development trend of this kind of fire. It has practical application value and theoretical guiding significance for fire prediction, prevention and rescue. At the same time, the research in this field is helpful to enrich and perfect the theoretical system of mobile flame diffusion flame, and has guiding significance for the efficient use of energy in mobile flame combustion. However, there are few researches on the basic research of mobile flame diffusion at home and abroad, so far there is still not a clear understanding of the inherent nature and physical laws of mobile flame diffusion. In this paper, the flame image is obtained by the experiment of moving fire source diffusion flame in an infinite space. From the angle of flame force field and heat, the average gray scale, flame area, flame inclination angle and flame linear velocity of flame image are analyzed. In order to reveal the combustion mechanism and influence law of the moving flame diffusion flame, the relationship between the radius of the rotating axis and the distance between the flame and the flame is revealed. In this paper, an infinite space experimental platform of moving fire source with circular motion is set up. Flame photos are obtained by Lightning RDT high-speed camera and synchronous measurement control computer, and the flame images are preprocessed under Matlab software. The results show that the standard grayscale image processing in television industry, the median filter method to eliminate noise interference, and the Canny operator to detect the flame edge image can get a better image processing effect. On the basis of image preprocessing, the characteristics of moving flame diffusion image are extracted and summarized. The experimental results show that the average gray value of flame image decreases first and then rises and then decreases significantly with the change of flame linear velocity, and the flame area increases first and then decreases with the change of flame linear velocity. With the increase of the linear velocity of the flame, the angle of flame inclination increases rapidly at the beginning, but the amplitude increases slowly after reaching a certain critical value. The reason is that when the linear velocity of the first stage is not large, the heat dissipation of the air flow is greater than the heat produced, the flame temperature drops slightly, and the average gray value of the flame image decreases slightly. The increase of air disturbance intensifies the mixing degree of fuel and air, and the flame temperature decreases slightly, which results in the increase of flame area. In the second stage, when the linear velocity of the flame is to a certain extent, the heat generated is larger than the heat dissipation, and the flame temperature rises slightly. In the third stage, when the moving velocity of the flame source reaches a higher speed, the amount of combustion is greatly reduced, the flame temperature is greatly decreased, and the average gray value of the flame image is also reduced when the gas flow takes away the fuel greatly, and the flame image grayscale value increases slightly. In the second and third stages, the mixture of fuel and air reaches its limit and too much air will take away more heat and fuel to reduce the area of the flame. The flame inclination angle increases rapidly at the beginning due to the increase of air resistance, and then decreases to offset the influence of flame linear velocity after reaching the critical value, and the increase of flame inclination angle is relatively flat. The above research realizes the extraction and analysis of the flame characteristics under the moving fire source motion, and provides a certain experimental and theoretical basis for the study of the mechanism of moving fire source.
【學位授予單位】：華南理工大學
【學位級別】：碩士
【學位授予年份】：2013
【分類號】：X951;TP391.41

【參考文獻】

相關(guān)期刊論文 前10條

1 閆治國,楊其新;秦嶺特長公路隧道火災溫度場分布試驗研究[J];地下空間;2003年02期

2 屈璐;陳超;楊英霞;任明亮;;地鐵列車區(qū)間隧道著火時行車安全性的討論[J];地下空間與工程學報;2007年05期

3 白衛(wèi)東,嚴建華,池涌,馬增益,張清宇,林彬,倪明江,岑可法;基于圖像技術(shù)和PCA方法的火焰監(jiān)測研究[J];動力工程;2004年01期

4 白衛(wèi)東,嚴建華,馬增益,王飛,張清宇,林彬,倪明江,岑可法;基于支持向量機的火焰狀態(tài)識別方法[J];動力工程;2004年04期

5 吳晉湘,王恩宇,劉聯(lián)勝;大加速度場中熄火試驗的研究[J];工程熱物理學報;1999年06期

6 孔文俊,杜文鋒,張孝謙;重力對擴散射流火焰動態(tài)特性的影響[J];工程熱物理學報;2000年03期

7 杜文鋒,孔文俊,張孝謙;微重力下環(huán)境壓力對火焰?zhèn)鞑サ挠绊慬J];工程熱物理學報;2001年06期

8 黃顯峰,趙黛青,張春林,山下博史;微尺度擴散火焰特性的數(shù)值解析[J];工程熱物理學報;2005年05期

9 張海;樊融;田雪沁;許考;湯根土;王雙峰;萬士昕;;加壓條件下甲烷/空氣預混火焰可燃極限的微重力實驗研究[J];工程熱物理學報;2010年01期

10 趙平輝;葉桃紅;陸陽;陳義良;;一種新的層流擴散火焰面建庫模型的研究[J];工程熱物理學報;2010年06期

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