圓周運(yùn)動移動火源擴(kuò)散火焰圖像特征及其規(guī)律
發(fā)布時間：2018-10-04 20:45
【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(zāi)事故也日趨增多。這類火災(zāi)的火源點(diǎn)往往處于運(yùn)動狀態(tài)且與空氣產(chǎn)生相對運(yùn)動，從而形成移動火源。移動火源擴(kuò)散燃燒火焰特征的研究是準(zhǔn)確評估這類火災(zāi)發(fā)展趨勢的基礎(chǔ)工作，對火災(zāi)的預(yù)測、防范和救援具有實(shí)際應(yīng)用價值和理論指導(dǎo)意義。同時該領(lǐng)域的研究有助于豐富和完善移動火源擴(kuò)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(dǎo)意義。但目前國內(nèi)外學(xué)者對移動火源擴(kuò)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(kuò)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(kuò)散火焰在無限大空間圓周運(yùn)動的實(shí)驗(yàn)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(kuò)散火焰的燃燒機(jī)理和影響規(guī)律。 文中搭建了無限大空間圓周運(yùn)動移動火源實(shí)驗(yàn)臺，通過Lightning RDT高速攝像儀以及同步測量控制計算機(jī)獲得火焰照片，并在Matlab軟件下對火焰圖像進(jìn)行預(yù)處理。通過研究表明，先用電視工業(yè)的標(biāo)準(zhǔn)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(yù)處理的基礎(chǔ)上，對移動火源擴(kuò)散火焰圖像特征進(jìn)行提取和變化規(guī)律總結(jié)。實(shí)驗(yàn)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��；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(dá)某個臨界值之后增大的幅度變緩慢。究其原因認(rèn)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(dǎo)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(yùn)動速度達(dá)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(dá)到極限以及過大的氣流會帶走更多熱量和燃料導(dǎo)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(dá)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(shí)現(xiàn)了對移動火源運(yùn)動下火焰特征提取與規(guī)律分析，為移動火源的機(jī)理研究提供了一定的實(shí)驗(yàn)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(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：X951;TP391.41
本文編號：2251823
[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(xué)位授予單位】：華南理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2013
【分類號】：X951;TP391.41
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