本文選題：擴(kuò)散射流火焰　切入點(diǎn)：高原低氧低壓環(huán)境　出處：《中國科學(xué)技術(shù)大學(xué)》2015年博士論文　論文類型：學(xué)位論文

【摘要】：擴(kuò)散射流火焰因易于控制而在工業(yè)燃燒設(shè)備中應(yīng)用十分廣泛,但是一些不受控制的擴(kuò)散射流火焰也能給人們帶來巨大傷害。近年來,因燃?xì)夤艿榔屏研纬傻臄U(kuò)散射流火災(zāi)事故頻繁發(fā)生,造成了極大的人員傷亡和財產(chǎn)損失。因此,研究擴(kuò)散射流火焰燃燒行為特征對工業(yè)燃燒設(shè)備的設(shè)計和安全高效運(yùn)行以及相關(guān)的火災(zāi)安全問題都具有重要的意義。 前人對常規(guī)條件下的擴(kuò)散射流火焰燃燒行為已開展了大量的研究,且形成了較為成熟的理論。但是,對一些特殊環(huán)境條件(例如,高原低氧低壓環(huán)境,低壓與環(huán)境風(fēng)耦合環(huán)境以及微重力環(huán)境等)下的擴(kuò)散射流火焰燃燒行為,人們卻研究得相對較少。隨著經(jīng)濟(jì)的發(fā)展和科技的進(jìn)步,人們在這種特殊環(huán)境下的生產(chǎn)活動卻越來越頻繁。因此,十分有必要開展針對性的研究,以揭示擴(kuò)散射流火焰在這種特殊環(huán)境下的燃燒行為特性,完善相關(guān)的火災(zāi)動力學(xué)理論,并為火災(zāi)防治技術(shù)的開發(fā)和改進(jìn)提供理論和數(shù)據(jù)支持。 本文采用理論分析和實(shí)驗(yàn)研究相結(jié)合的方法,對不同環(huán)境條件下的擴(kuò)散射流火焰行為特征開展了研究。為此,我們分別設(shè)計了：(1)合肥和拉薩自由擴(kuò)散射流火焰行為特性實(shí)驗(yàn)研究裝置；(2)合肥和拉薩水平環(huán)境風(fēng)作用下擴(kuò)散射流火焰行為特性實(shí)驗(yàn)研究裝置；和(3)微重力和常重力伴流擴(kuò)散射流火焰行為實(shí)驗(yàn)研究裝置。通過對典型特征參數(shù)(火焰形態(tài)、火焰中心線溫度、火焰輻射、火焰推舉和吹熄行為)的分析,結(jié)合火災(zāi)和燃燒動力學(xué)經(jīng)典理論,揭示了三種不同特殊環(huán)境條件下擴(kuò)散射流火焰行為演化機(jī)制,并建立了相應(yīng)的無量綱數(shù)學(xué)表征模型。具體的研究工作包括： 研究了高原低氧低壓環(huán)境和平原常壓常氧環(huán)境下自由擴(kuò)散射流火焰高度、火焰中心線溫度、火焰輻射和推舉行為。通過研究合肥和拉薩兩地火焰高度的差別,發(fā)現(xiàn)低壓下的平均火焰高度要顯著高于常壓環(huán)境下的平均火焰高度。通過分析火羽流基本物理模型,建立了量化兩地空氣卷吸差別的方法,對經(jīng)典火焰高度物理模型進(jìn)行了修正。引入了虛點(diǎn)源理論,考慮其與火焰火源功率、火焰尺寸和大氣環(huán)境等因素之間的耦合關(guān)系,得到了兩種氣壓環(huán)境下虛點(diǎn)源無量綱模型。并通過虛點(diǎn)源模型修正了自由擴(kuò)散射流火焰中心線溫度分布三段模型。另外,通過實(shí)驗(yàn)還發(fā)現(xiàn)了氣壓越低推舉高度越大的現(xiàn)象。通過分析經(jīng)典火焰推舉模型及其中受到壓力影響的關(guān)鍵性因素,發(fā)現(xiàn)了不同氣壓下火焰推舉產(chǎn)生差異的根本原因,修正了Kalghatgi經(jīng)典火焰推舉模型。 研究了合肥和拉薩兩種氣壓條件水平環(huán)境風(fēng)作用下的擴(kuò)散射流火焰演化過程,發(fā)現(xiàn)：1)在常壓環(huán)境中,隨著風(fēng)速的增加,火焰形態(tài)和顏色都會發(fā)生顯著的變化�；鹧孥E線長度先隨著風(fēng)速的增加而逐步減小,而后會達(dá)到一個最小值,最后將保持相對穩(wěn)定或者被拉長。而在低壓環(huán)境中,隨著風(fēng)速的增加,火焰長度則保持單調(diào)減小的趨勢。另外,通過分析經(jīng)典的理論模型,得到了兩種氣壓環(huán)境下火焰長度的預(yù)測模型；2)還研究了高原低壓和平原常壓水平環(huán)境風(fēng)作用下火焰的吹熄極限,發(fā)現(xiàn)兩種環(huán)境下吹熄臨界風(fēng)速都先隨著燃料噴出速度的增加而逐步增加,到達(dá)一個最大值之后又隨著燃料噴出速度的增加而減小。同時,發(fā)現(xiàn)低氧低壓環(huán)境(64kPa)下的吹熄臨界風(fēng)速顯著低于常壓環(huán)境(100kPa)(約為1/3)。研究了環(huán)境風(fēng)作用下的火焰吹熄機(jī)制,建立了基于Damkohler數(shù)、耦合壓力影響的擴(kuò)散射流火焰吹熄極限數(shù)學(xué)表征模型。 最后,通過開展落塔微重力環(huán)境下的擴(kuò)散射流火焰行為實(shí)驗(yàn),觀察到微重力條件下擴(kuò)散射流火焰高度更高,火焰更明亮,碳黑生成更多的現(xiàn)象。同時,還研究了受伴流作用的擴(kuò)散射流火焰吹熄過程,發(fā)現(xiàn)微重力下火焰吹熄臨界伴流空氣速度要顯著大于常重力下的結(jié)果。
[Abstract]:Jet diffusion flame is easy to control in industrial combustion equipment is widely used, but some uncontrolled jet diffusion flame can also bring great harm to the people. In recent years, due to gas pipeline rupture diffusion jet fire accident formation occurred frequently, caused great casualties and property losses. Therefore, all have the important significance of jet diffusion flame combustion behaviors of industrial combustion equipment design and the safe and efficient operation and related fire safety problems.
The predecessors have carried out a lot of research on jet diffusion flame combustion behavior under conventional conditions, and formed a relatively mature theory. But, for some special environmental conditions (e.g., low altitude hypoxia environment, low pressure and environmental wind coupling environment and microgravity environment etc.) the combustion behavior of jet diffusion flame is studied under the people relatively small. With the development of economy and the progress of science and technology, in the special environment of production activities of people is more and more frequent. Therefore, it is necessary to study the combustion behavior in order to reveal the jet diffusion flame in the special environment, improve the fire dynamics theory, and for the development of fire prevention and control the improvement of technology and provide theoretical and data support.
This paper uses the method of theoretical analysis combined with experimental study, the jet diffusion flame behavior under different environmental conditions to carry out the research. Therefore, we design: (1) Hefei and Lhasa free diffusion behavior experimental study of flame jet device; (2) diffusion device experimental research on flame behavior of jet fan in Hefei and the level of Lhasa environment; and (3) microgravity and normal gravity coflow diffusion flame behavior experimental study of jet device. Through the parameters of the typical features (flame shape, flame temperature and flame radiation center line, and blow out the flame press behavior) analysis, combined with the fire and combustion kinetics of the classical theory, reveals the evolution mechanism of diffusion the jet flame behavior of three kinds of special conditions, and established the dimensionless mathematical characterization of the corresponding model. The research work includes:
Study on low altitude hypoxia environment and plain atmospheric oxygen environment free jet diffusion flame height, flame temperature and flame radiation center line, press behavior. Through the study of Hefei and Lhasa found that the average flame height difference, flame height, average flame height to low pressure higher than atmospheric environment. Through the analysis of fire plume the basic physical model, establishes a quantitative difference between the two air entrainment method, the classical physics flame height model was modified. The virtual point source theory, considering the fire and fire power, the coupling relationship between flame size and atmospheric environment and other factors, we obtain two kinds of pressure under the environment of virtual point source dimensionless model and fixed free jet diffusion flame center line three temperature distribution model through the virtual point source model. In addition, it was also found that the lower the air pressure is more highly recommended Phenomenon. By analyzing the classical flame lift model and the key factors which are affected by pressure, we find the root cause of the difference in the flame lift under different barometric pressure, and modify the classical Kalghatgi flame lift model.
Study on the jet diffusion flame in Hefei and Lhasa two pressure level under the action of wind environment evolution process, it is found that: 1) in the atmospheric environment, with the increase of wind speed, flame shape and color will change significantly. The flame trace length first increases as wind speed decreases gradually, and will reach a minimum the final value will remain relatively stable or elongated. While in low pressure environment, with the increase of wind speed, the flame length is monotonically decreasing. In addition, through the analysis of classical theory model, and obtained two kinds of pressure environment prediction model of flame length; 2) of Plateau and plain low blow out limit the level of atmospheric environment under the action of wind fire, found that two kinds of environment are first with the increase of blow out the critical wind speed of the fuel spray and gradually increased to a maximum and then with fuel injection Speed increases. At the same time, found that the low pressure environment (64kPa) blew out under the critical wind speed was significantly lower than that of atmospheric environment (100kPa) (about 1/3). The mechanism of environmental wind blew out the flame, is established based on the Damkohler number, expanding the scattering coupling pressure effect flow flame blowoff limit mathematical representation model.
Finally, through the development of diffusion jet flame behavior experiment tower under microgravity environment, the observed jet diffusion flame in microgravity flame height higher, more bright, more soot formation phenomenon. At the same time, has also been studied by diffusion jet flame wake effect blew out the process, found that microgravity flame blow out air flow with critical the speed is bigger than that under normal gravity results.

【學(xué)位授予單位】：中國科學(xué)技術(shù)大學(xué)
【學(xué)位級別】：博士
【學(xué)位授予年份】：2015
【分類號】：TK16

【參考文獻(xiàn)】

相關(guān)期刊論文 前4條

1 張夏;載人航天器火災(zāi)安全研究進(jìn)展[J];力學(xué)進(jìn)展;2005年01期

2 陳志斌;胡隆華;霍然;祝實(shí);;基于圖像相關(guān)性提取的火焰振蕩頻率[J];燃燒科學(xué)與技術(shù);2008年04期

3 戴金星,夏新宇,衛(wèi)延召;中國天然氣資源及前景分析——兼論“西氣東輸”的儲量保證[J];石油與天然氣地質(zhì);2001年01期

4 閻一新;;如何正確使用轉(zhuǎn)子流量計修正公式[J];山西化工;1988年03期

，

本文編號：1563933