【摘要】：由于地鐵列車的快捷、方便、舒適、環(huán)保及節(jié)能等優(yōu)點(diǎn),其在有效解決城市的交通擁堵問題上扮演了越來越重要的角色。然而由于地鐵列車常年在地下或隧道中運(yùn)行,一旦遇到火災(zāi),車上大量的旅客的逃生及救援相當(dāng)困難,從而造成嚴(yán)重的人員傷亡、財(cái)產(chǎn)損失及環(huán)境污染。因此地鐵列車的火災(zāi)安全引起了越來越多的關(guān)注。而了解不同外部條件下的地鐵列車車廂內(nèi)裝材料的熱解及燃燒特性是地鐵列車火災(zāi)安全非常重要的組成部分,而且可以為地下軌道交通運(yùn)輸系統(tǒng)的消防安全設(shè)計(jì)、滅火及救援提供必要的基礎(chǔ)數(shù)據(jù)及理論支撐。地鐵列車車廂內(nèi)部的固定可燃物主要由地板布及座椅組成。典型的地鐵列車車廂內(nèi)裝材料包括商用的阻燃三元乙丙橡膠地板布及酚醛樹脂玻璃鋼座椅材料被用于本文的研究。本文探究了外部條件對上述兩種材料的熱解特性、熱解過程中的反應(yīng)機(jī)理及揮發(fā)性產(chǎn)物以及燃燒特性的影響,揭示了試樣厚度對酚醛樹脂玻璃鋼燃燒特性的影響,得到了上述兩種材料的動(dòng)力學(xué)參數(shù)及燃燒特性參數(shù)。本文的主要工作及結(jié)論歸納如下：揭示了升溫速率、溫度及環(huán)境氣氛對阻燃三元乙丙橡膠及酚醛樹脂玻璃鋼熱解特性的影響：(1)隨著升溫速率的升高,熱重曲線會(huì)向高溫區(qū)移動(dòng),總質(zhì)量損失基本保持不變。對于阻燃三元乙丙橡膠而言,其熱失重峰的數(shù)目可能會(huì)隨著升溫速率的增加而增多。其在氮?dú)鈿夥障碌淖畲鬅崾е厮俾孰S著升溫速率的增大而降低,而其在空氣氣氛下的最大熱失重速率與升溫速率之間并沒有明確的變化規(guī)律。對于酚醛樹脂玻璃鋼而言,隨著升溫速率的增大,其在氮?dú)鈿夥障碌淖畲鬅崾е厮俾驶颈３植蛔?而其在空氣氣氛下的最大熱失重速率變小。阻燃三元乙丙橡膠的熱解過程主要分為三個(gè)階段,而酚醛樹脂玻璃鋼的熱解過程主要分為兩個(gè)階段。(2)在等溫條件下,阻燃三元乙丙橡膠的總質(zhì)量損失隨著溫度的升高而增大。氮?dú)鈿夥障碌姆尤渲Ａт摰目傎|(zhì)量損失大致隨著溫度的升高而增大,然而空氣氣氛下的酚醛樹脂玻璃鋼的總質(zhì)量損失在溫度區(qū)間403-433 K內(nèi)隨著溫度的增加而減小,在溫度區(qū)間713-863 K內(nèi)隨著溫度的增加而基本保持不變。(3)與氮?dú)鈿夥障略嚇拥臒峤庀啾?空氣氣氛下試樣的熱解會(huì)被加快。對于阻燃三元乙丙橡膠而言,當(dāng)其處于非等溫條件時(shí),空氣氣氛下出現(xiàn)了一個(gè)新的熱失重峰,該峰位于氮?dú)鈿夥障伦詈笠粋�(gè)熱失重峰之后。此外,其在空氣氣氛下的最大及平均熱失重速率、總質(zhì)量損失會(huì)比氮?dú)鈿夥障碌囊��；诜堑葴卦囼?yàn)結(jié)果得到的氮?dú)鈿夥障碌钠骄罨芗盎诘葴卦囼?yàn)結(jié)果得到的氮?dú)鈿夥障碌娜只罨芫瓤諝鈿夥障碌囊�。對于酚醛樹脂玻璃鋼而�?在空氣氣氛下的非等溫實(shí)驗(yàn)中,當(dāng)試樣處于溫度區(qū)間450-600 K時(shí),其質(zhì)量隨溫度的升高而增加。此外,在空氣氣氛下的等溫實(shí)驗(yàn)中,當(dāng)試樣處于溫度區(qū)間403-433 K時(shí),其質(zhì)量也隨時(shí)間的推移而出現(xiàn)增加的情況。但是上述的酚醛樹脂玻璃鋼的質(zhì)量隨著溫度增大而增加的現(xiàn)象并沒有出現(xiàn)在氮?dú)鈿夥涨樾萎?dāng)中。除此之外,其在空氣氣氛下的最大及平均熱失重速率、總質(zhì)量損失會(huì)比氮?dú)鈿夥障碌囊��；诜堑葴卦囼?yàn)結(jié)果得到的氮?dú)鈿夥障碌钠骄罨鼙瓤諝鈿夥障碌囊?然而基于等溫實(shí)驗(yàn)結(jié)果得到的氮?dú)鈿夥障碌娜只罨鼙瓤諝鈿夥障碌囊汀７治隽瞬煌h(huán)境氣氛下的阻燃三元乙丙橡膠及酚醛樹脂玻璃鋼熱解過程當(dāng)中的反應(yīng)機(jī)理及揮發(fā)性產(chǎn)物：(1)對于阻燃三元乙丙橡膠而言,氫氧化鋁、氫氧化鎂及三元乙丙橡膠的分解主要導(dǎo)致了其三個(gè)熱失重階段的出現(xiàn)。氫氧化鋁在惰性及含氧氣氛下的分解區(qū)間分別為500-673 K及500-653 K。氫氧化鎂在惰性及含氧氣氛下的分解區(qū)間分別為500-753 K及500-703 K。氫氧化鋁及氫氧化鎂的分解產(chǎn)生了大量的水。在惰性及含氧氣氛下,少量的脂肪烴小分子及烷基苯分別在溫度區(qū)間500-700 K及500-680 K內(nèi)逸出,可能是由于三元乙丙橡膠上的支鏈從主鏈上斷開及試樣中的其他有機(jī)物分解所造成的。在惰性及含氧氣氛下的溫度分別超過700 K及680 K時(shí),隨著三元乙丙橡膠主鏈上的化學(xué)鍵發(fā)生斷裂及試樣中其他有機(jī)物的進(jìn)一步分解,大量的碳?xì)浠衔锓肿右莩�。與此同時(shí),在惰性及含氧氣氛下的溫度分別超過730 K及600 K時(shí),試樣的分解產(chǎn)生了大量的二氧化碳。在含氧氣氛下的溫度超過730 K時(shí),大量的一氧化碳逸出,而惰性氣氛下并沒有檢測到一氧化碳的產(chǎn)生。在惰性及含氧氣氛下的溫度分別超過700 K及650 K時(shí),有毒氣體如氟化氫、甲醛、氯化氫、甲酸、二氧化硫、二硫化碳、溴化氫、苯胺等被檢測到。由于一氧化碳及氰化氫的劇毒性,需要重點(diǎn)關(guān)注含氧氣氛下的這兩種氣體的產(chǎn)生。(2)對于酚醛樹脂玻璃鋼而言,苯酚及其衍生物之間發(fā)生的交聯(lián)作用以及交聯(lián)作用的斷裂主要導(dǎo)致了其兩個(gè)熱失重階段的出現(xiàn)。惰性及含氧氣氛下的第一個(gè)熱失重階段對應(yīng)的溫度區(qū)間分別為400-638 K及400-600 K。在第一個(gè)熱失重階段,大量的雙酚化合物及其衍生物逸出。小分子如氫氣、甲烷、水蒸氣、乙炔、乙烯、甲醛、甲醇、二氧化碳、一氧化碳、甲酸、丁烷、甲酚等被檢測到。惰性及含氧氣氛下的第二個(gè)熱失重階段對應(yīng)的溫度區(qū)間分別為638-1100 K及600-900 K。在第二個(gè)熱失重階段,酚醛樹脂玻璃鋼的主鏈發(fā)生斷裂,大量的苯、苯酚及其衍生物如甲苯、甲酚、二甲苯酚等被檢測到。由于酚醛樹脂玻璃鋼主鏈上的羥甲基及羥基的脫去,少量的水逸出。除此之外,甲酸、苯胺、二氧化碳及一氧化碳也被檢測到。在第二個(gè)熱失重階段產(chǎn)生的二氧化碳及一氧化碳的量比第一個(gè)熱失重階段產(chǎn)生的二氧化碳及一氧化碳的量要多。值得注意的是：在含氧氣氛下檢測到了二氧化硫的逸出,然而在惰性氣氛下并沒有檢測到二氧化硫的產(chǎn)生。揭示了外加熱輻射通量對阻燃三元乙丙橡膠及酚醛樹脂玻璃鋼燃燒特性的影響,分析了試樣厚度對酚醛樹脂玻璃鋼燃燒特性的影響：(1)對于阻燃三元乙丙橡膠而言,根據(jù)外加熱輻射通量的不同,可將其熱分解行為分成三個(gè)區(qū)域：(a)區(qū)域1(外加熱輻射通量≤35 kW/m2)：產(chǎn)生的炭層基本未破裂；(b)區(qū)域2(35 kW/m2外加熱輻射通量≤45 kW/m2)：產(chǎn)生的炭層部分破裂：(c)區(qū)域3(外加熱輻射通量45 kW/m2)：產(chǎn)生的炭層完全破裂。處于區(qū)域2及3的試樣的熱分解過程可分為6個(gè)階段：點(diǎn)燃前的初級分解階段(階段Ⅰ)、點(diǎn)燃后的加速分解階段(階段Ⅱ)、產(chǎn)生大量炭層的分解減弱階段(階段Ⅲ)、炭層破裂后的進(jìn)一步分解階段(階段Ⅳ)、產(chǎn)生少量炭層的第二次分解減弱階段(階段V)及無焰氧化階段(階段Ⅵ)。然而處于區(qū)域1的試樣的熱分解過程中僅僅存在4個(gè)階段(其中階段Ⅳ及Ⅴ消失)。當(dāng)外加熱輻射通量大于35 kW/m2時(shí),熱釋放速率(HRR)曲線上出現(xiàn)了兩個(gè)峰值,并且在兩個(gè)峰之間出現(xiàn)了一個(gè)準(zhǔn)穩(wěn)態(tài)階段,同時(shí)有效燃燒熱(EHC)曲線上也出現(xiàn)了兩個(gè)峰值,而且EHC曲線上的第二個(gè)峰值大于第一個(gè)峰值。變換的點(diǎn)燃時(shí)間、質(zhì)量損失速率(MLR)的峰值和平均值、HRR的峰值和平均值、準(zhǔn)穩(wěn)態(tài)階段的HRR以及火災(zāi)增長系數(shù)(FGI)都隨著外加熱輻射通量的增加而線性增加。當(dāng)外加熱輻射通量從25kW/m2升高到50 kW/m2時(shí),總釋熱量線性增大。當(dāng)外加熱輻射通量處于50、55、60和65 kW/m2時(shí),總釋熱量基本保持不變。熱穿透厚度隨密度與外加熱輻射通量的比值的增大而線性增大。(2)對于酚醛樹脂玻璃鋼而言,其熱分解過程同樣可分為6個(gè)階段：點(diǎn)燃前的初級分解階段(階段Ⅰ)、點(diǎn)燃后的加速分解階段(階段Ⅱ)、產(chǎn)生大量炭層的分解減弱階段(階段Ⅲ)、炭層破裂后的進(jìn)一步分解階段(階段Ⅳ)、產(chǎn)生少量炭層的第二次分解減弱階段(階段V)及無焰氧化階段(階段Ⅵ)。點(diǎn)燃時(shí)間隨著試樣厚度的增加而增大。隨著外加熱輻射通量的增加,不同厚度的試樣的點(diǎn)燃時(shí)間的差異縮小。隨著試樣厚度的增加,質(zhì)量損失系數(shù)減小,然而平均MLR增大。MLR曲線上出現(xiàn)了兩個(gè)峰值。3mm厚的試樣的平均HRR大于5 mm厚的試樣的平均HRR,8 mm厚的試樣的平均HRR在這三者當(dāng)中是最大的。隨著試樣厚度的增大,總釋熱量也隨之增加。隨著外加熱輻射通量的增大,變換的點(diǎn)燃時(shí)間、MLR的峰值和平均值、HRR的最大值和平均值及FGI都隨之線性增加。隨著密度和外加熱輻射通量比值的增加,熱穿透厚度也隨之線性增大。獲得并驗(yàn)證了阻燃三元乙丙橡膠及酚醛樹脂玻璃鋼的燃燒特性參數(shù)：基于錐形量熱儀特征參數(shù)與外加熱輻射通量之間的關(guān)系,并結(jié)合理論分析,推理得到了阻燃三元乙丙橡膠及酚醛樹脂玻璃鋼的燃燒特性參數(shù),包括臨界熱輻射通量、最小熱輻射通量、點(diǎn)燃溫度、汽化潛熱及燃燒熱,并對其正確性進(jìn)行了驗(yàn)證。
[Abstract]:Due to the advantages of fast, convenient, comfortable, environmental protection and energy saving, subway trains play an increasingly important role in effectively solving the traffic jam problem in the city. However, because the subway trains run in the underground or tunnel all year round, once the fire occurs, it is very difficult for a large number of passengers on the train to escape and rescue, thus causing serious problems. As a result, more and more attentions have been paid to the fire safety of subway trains. Understanding the pyrolysis and combustion characteristics of materials installed in the carriages of subway trains under different external conditions is a very important part of the fire safety of subway trains, and it can be used to eliminate the underground rail transit transportation system. Fixed combustibles in subway carriages are mainly composed of floor cloth and seats. Typical materials used in subway carriages include commercial flame retardant EPDM floor cloth and phenolic resin FRP seats. In this paper, the effects of external conditions on the pyrolysis characteristics, reaction mechanism, volatile products and combustion characteristics of the two materials were investigated. The effects of sample thickness on the combustion characteristics of phenolic resin FRP were revealed. The kinetic parameters and combustion characteristics of the two materials were obtained. The results are summarized as follows: The effects of heating rate, temperature and ambient atmosphere on the pyrolysis characteristics of flame retardant EPDM and phenolic resin FRP are revealed: (1) With the increase of heating rate, the thermogravimetric curve will move to the high temperature zone, and the total mass loss will remain basically unchanged. The maximum thermogravimetric rate decreases with the increase of heating rate in nitrogen atmosphere, but there is no definite change rule between the maximum thermogravimetric rate and heating rate in air atmosphere. The pyrolysis process of flame retardant EPDM can be divided into three stages, and the pyrolysis process of phenolic resin FRP can be divided into two stages. (2) The total mass loss of flame retardant EPDM can be divided into two stages under isothermal conditions. The total mass loss of phenolic resin FRP in nitrogen atmosphere increases with the increase of temperature. However, the total mass loss of phenolic resin FRP in air atmosphere decreases with the increase of temperature in the temperature range 403-433 K, and increases with the increase of temperature in the temperature range 713-863 K. (3) Compared with the pyrolysis of samples in nitrogen atmosphere, the pyrolysis of samples in air atmosphere will be accelerated. For flame retardant EPDM, a new thermogravimetric peak appears in air atmosphere when it is in non-isothermal condition. The peak is located after the last thermogravimetric peak in nitrogen atmosphere. The maximum and average thermal gravimetric loss rates in air are smaller than those in nitrogen. The average activation energy in nitrogen atmosphere obtained from non-isothermal test results and the global activation energy in nitrogen atmosphere obtained from isothermal test results are higher than that in air. For phenolic resin FRP, the total mass loss in nitrogen atmosphere is smaller than that in air. In the non-isothermal experiment under air atmosphere, the mass of the sample increases with the increase of temperature when it is in the temperature range 450-600 K. In addition, the mass of the sample increases with time when it is in the temperature range 403-433 K in the isothermal experiment under air atmosphere. In addition, the maximum and average thermogravimetric rate in air is larger than that in nitrogen. The average activation energy in non-isothermal nitrogen is higher than that in air, but the base is higher than that in air. The global activation energy in nitrogen atmosphere is lower than that in air atmosphere. The reaction mechanism and volatile products in the pyrolysis process of flame retardant EPDM and phenolic resin FRP in different ambient atmospheres are analyzed: (1) For flame retardant EPDM, aluminium hydroxide, magnesium hydroxide and triethylene propylene hydroxide are used. The decomposition of EPDM mainly results in three thermogravimetric stages. The decomposition intervals of aluminum hydroxide in inert and oxygen atmosphere are 500-673 K and 500-653 K respectively. The decomposition intervals of magnesium hydroxide in inert and oxygen atmosphere are 500-753 K and 500-703 K respectively. Water. In inert and oxygen atmosphere, a small amount of aliphatic hydrocarbon small molecules and alkylbenzene escaped in the temperature range 500-700 K and 500-680 K, respectively, possibly due to the branching chain breaking off from the main chain of EPDM rubber and the decomposition of other organic compounds in the sample. In inert and oxygen atmosphere, the temperature exceeded 700 K and 680 K, respectively. With the breakdown of chemical bonds on the main chain of EPDM and the further decomposition of other organic compounds in the sample, a large number of hydrocarbon molecules escaped. At the same time, when the temperatures in inert and oxygen atmosphere exceeded 730 K and 600 K respectively, the decomposition of the sample produced a large amount of carbon dioxide. At 30 K, a large amount of carbon monoxide escaped, but no carbon monoxide was detected in the inert atmosphere. Toxic gases such as hydrogen fluoride, formaldehyde, hydrogen chloride, formic acid, sulfur dioxide, carbon disulfide, hydrogen bromide, aniline, etc. were detected when the temperatures in the inert and oxygen atmosphere exceeded 700 K and 650 K, respectively. For phenol-formaldehyde FRP, the cross-linking and the breakage of the cross-linking between phenol and its derivatives mainly lead to the occurrence of two thermogravimetric stages. The temperature corresponding to the first thermogravimetric stage in inert and oxygen atmosphere. In the first thermogravimetric stage, a large number of bisphenols and their derivatives escaped. Small molecules such as hydrogen, methane, water vapor, acetylene, ethylene, formaldehyde, methanol, carbon dioxide, carbon monoxide, formic acid, butane, cresol, etc. were detected. The temperature ranges are 638-1100 K and 600-900 K, respectively. In the second thermogravimetric stage, the main chain of phenolic resin FRP breaks and a large number of benzene, phenol and its derivatives such as toluene, cresol, xylene are detected. Due to the removal of hydroxyl methyl and hydroxyl groups from the main chain of phenolic resin FRP, a small amount of water escapes. Aniline, carbon dioxide and carbon monoxide were also detected. More carbon dioxide and carbon monoxide were produced in the second thermogravimetric stage than in the first thermogravimetric stage. Sulfur dioxide was detected. The effect of external heating radiation flux on the combustion characteristics of flame retardant EPDM and phenolic resin FRP was revealed. The influence of sample thickness on the combustion characteristics of phenolic resin FRP was analyzed. (1) For flame retardant EPDM, the heat content of the flame retardant EPDM could be determined according to the different external heating radiation flux. The decomposition behavior is divided into three regions: (a) region 1 (external heating radiation flux < 35 kW / m2): the resulting carbon layer is basically unbroken; (b) region 2 (35 kW / m2 external heating radiation flux < 45 kW / m2): the resulting carbon layer is partially broken; (c) region 3 (external heating radiation flux 45 kW / m2): the resulting carbon layer is completely broken. The decomposition process can be divided into six stages: the primary decomposition stage before ignition (stage I), the accelerated decomposition stage after ignition (stage II), the decomposition weakening stage (stage III), the further decomposition stage (stage IV), the second decomposition weakening stage (stage V) and the flameless oxidation stage (stage V). However, there are only four stages (stage IV and V disappear) in the thermal decomposition process of the sample in region 1. When the external heating radiation flux is greater than 35 kW/m2, two peaks appear on the heat release rate (HRR) curve, and a quasi-steady state stage appears between the two peaks, and the effective combustion heat (EHC) curve also appears. There are two peaks, and the second peak on the EHC curve is larger than the first one. The ignition time, the peak and average value of mass loss rate (MLR), the peak and average value of HRR, the quasi-steady state HRR and the fire growth coefficient (FGI) all increase linearly with the increase of the external heating radiation flux. The total heat release increases linearly from 25 kW/m2 to 50 kW/m2. When the external heating radiation fluxes are 50,55,60 and 65 kW/m2, the total heat release remains unchanged. The thermal penetration thickness increases linearly with the increase of the ratio of the density to the external heating radiation fluxes. (2) For phenolic resin FRP, the thermal decomposition process can also be divided into six parts. Stage: Primary decomposition stage before ignition (Stage I), accelerated decomposition stage after ignition (Stage II), decomposition weakening stage (Stage III), further decomposition stage (Stage IV), second decomposition weakening stage (Stage V) and flameless oxidation stage (Stage VI) of a small amount of carbon layer after cracking. The ignition time of specimens with different thicknesses decreases with the increase of external heating radiation flux. The mass loss coefficient decreases with the increase of specimen thickness, but the average MLR increases. The average HRR of samples with mm thickness is the largest among the three. With the increase of sample thickness, the total heat release increases. With the increase of external heating radiation flux, the transition ignition time, the peak value and average value of MLR, the maximum and average value of HRR and FGI increase linearly. The combustion characteristic parameters of flame retardant EPDM and phenolic resin FRP were obtained and verified. Based on the relationship between the characteristic parameters of cone calorimeter and the radiation flux of external heating, the flame retardant EPDM and phenolic resin FRP were deduced by theoretical analysis. The combustion characteristic parameters, including critical heat radiation flux, minimum heat radiation flux, ignition temperature, latent heat of vaporization and combustion heat, were verified.
【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】：2016
【分類號(hào)】：U231.96;U270.4;TQ038
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本文編號(hào)：2232638