地铁列车车厢典型内装材料热解及燃烧特性研究
发布时间：2018-09-09 14:21
【摘要】：由于地铁列车的快捷、方便、舒适、环保及节能等优点,其在有效解决城市的交通拥堵问题上扮演了越来越重要的角色。然而由于地铁列车常年在地下或隧道中运行,一旦遇到火灾,车上大量的旅客的逃生及救援相当困难,从而造成严重的人员伤亡、财产损失及环境污染。因此地铁列车的火灾安全引起了越来越多的关注。而了解不同外部条件下的地铁列车车厢内装材料的热解及燃烧特性是地铁列车火灾安全非常重要的组成部分,而且可以为地下轨道交通运输系统的消防安全设计、灭火及救援提供必要的基础数据及理论支撑。地铁列车车厢内部的固定可燃物主要由地板布及座椅组成。典型的地铁列车车厢内装材料包括商用的阻燃三元乙丙橡胶地板布及酚醛树脂玻璃钢座椅材料被用于本文的研究。本文探究了外部条件对上述两种材料的热解特性、热解过程中的反应机理及挥发性产物以及燃烧特性的影响,揭示了试样厚度对酚醛树脂玻璃钢燃烧特性的影响,得到了上述两种材料的动力学参数及燃烧特性参数。本文的主要工作及结论归纳如下：揭示了升温速率、温度及环境气氛对阻燃三元乙丙橡胶及酚醛树脂玻璃钢热解特性的影响：(1)随着升温速率的升高,热重曲线会向高温区移动,总质量损失基本保持不变。对于阻燃三元乙丙橡胶而言,其热失重峰的数目可能会随着升温速率的增加而增多。其在氮气气氛下的最大热失重速率随着升温速率的增大而降低,而其在空气气氛下的最大热失重速率与升温速率之间并没有明确的变化规律。对于酚醛树脂玻璃钢而言,随着升温速率的增大,其在氮气气氛下的最大热失重速率基本保持不变,而其在空气气氛下的最大热失重速率变小。阻燃三元乙丙橡胶的热解过程主要分为三个阶段,而酚醛树脂玻璃钢的热解过程主要分为两个阶段。(2)在等温条件下,阻燃三元乙丙橡胶的总质量损失随着温度的升高而增大。氮气气氛下的酚醛树脂玻璃钢的总质量损失大致随着温度的升高而增大,然而空气气氛下的酚醛树脂玻璃钢的总质量损失在温度区间403-433 K内随着温度的增加而减小,在温度区间713-863 K内随着温度的增加而基本保持不变。(3)与氮气气氛下试样的热解相比,空气气氛下试样的热解会被加快。对于阻燃三元乙丙橡胶而言,当其处于非等温条件时,空气气氛下出现了一个新的热失重峰,该峰位于氮气气氛下最后一个热失重峰之后。此外,其在空气气氛下的最大及平均热失重速率、总质量损失会比氮气气氛下的要小。基于非等温试验结果得到的氮气气氛下的平均活化能及基于等温试验结果得到的氮气气氛下的全局活化能均比空气气氛下的要高。对于酚醛树脂玻璃钢而言,在空气气氛下的非等温实验中,当试样处于温度区间450-600 K时,其质量随温度的升高而增加。此外,在空气气氛下的等温实验中,当试样处于温度区间403-433 K时,其质量也随时间的推移而出现增加的情况。但是上述的酚醛树脂玻璃钢的质量随着温度增大而增加的现象并没有出现在氮气气氛情形当中。除此之外,其在空气气氛下的最大及平均热失重速率、总质量损失会比氮气气氛下的要大。基于非等温试验结果得到的氮气气氛下的平均活化能比空气气氛下的要高,然而基于等温实验结果得到的氮气气氛下的全局活化能比空气气氛下的要低。分析了不同环境气氛下的阻燃三元乙丙橡胶及酚醛树脂玻璃钢热解过程当中的反应机理及挥发性产物：(1)对于阻燃三元乙丙橡胶而言,氢氧化铝、氢氧化镁及三元乙丙橡胶的分解主要导致了其三个热失重阶段的出现。氢氧化铝在惰性及含氧气氛下的分解区间分别为500-673 K及500-653 K。氢氧化镁在惰性及含氧气氛下的分解区间分别为500-753 K及500-703 K。氢氧化铝及氢氧化镁的分解产生了大量的水。在惰性及含氧气氛下,少量的脂肪烃小分子及烷基苯分别在温度区间500-700 K及500-680 K内逸出,可能是由于三元乙丙橡胶上的支链从主链上断开及试样中的其他有机物分解所造成的。在惰性及含氧气氛下的温度分别超过700 K及680 K时,随着三元乙丙橡胶主链上的化学键发生断裂及试样中其他有机物的进一步分解,大量的碳氢化合物分子逸出。与此同时,在惰性及含氧气氛下的温度分别超过730 K及600 K时,试样的分解产生了大量的二氧化碳。在含氧气氛下的温度超过730 K时,大量的一氧化碳逸出,而惰性气氛下并没有检测到一氧化碳的产生。在惰性及含氧气氛下的温度分别超过700 K及650 K时,有毒气体如氟化氢、甲醛、氯化氢、甲酸、二氧化硫、二硫化碳、溴化氢、苯胺等被检测到。由于一氧化碳及氰化氢的剧毒性,需要重点关注含氧气氛下的这两种气体的产生。(2)对于酚醛树脂玻璃钢而言,苯酚及其衍生物之间发生的交联作用以及交联作用的断裂主要导致了其两个热失重阶段的出现。惰性及含氧气氛下的第一个热失重阶段对应的温度区间分别为400-638 K及400-600 K。在第一个热失重阶段,大量的双酚化合物及其衍生物逸出。小分子如氢气、甲烷、水蒸气、乙炔、乙烯、甲醛、甲醇、二氧化碳、一氧化碳、甲酸、丁烷、甲酚等被检测到。惰性及含氧气氛下的第二个热失重阶段对应的温度区间分别为638-1100 K及600-900 K。在第二个热失重阶段,酚醛树脂玻璃钢的主链发生断裂,大量的苯、苯酚及其衍生物如甲苯、甲酚、二甲苯酚等被检测到。由于酚醛树脂玻璃钢主链上的羟甲基及羟基的脱去,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检测到。在第二个热失重阶段产生的二氧化碳及一氧化碳的量比第一个热失重阶段产生的二氧化碳及一氧化碳的量要多。值得注意的是：在含氧气氛下检测到了二氧化硫的逸出,然而在惰性气氛下并没有检测到二氧化硫的产生。揭示了外加热辐射通量对阻燃三元乙丙橡胶及酚醛树脂玻璃钢燃烧特性的影响,分析了试样厚度对酚醛树脂玻璃钢燃烧特性的影响：(1)对于阻燃三元乙丙橡胶而言,根据外加热辐射通量的不同,可将其热分解行为分成三个区域：(a)区域1(外加热辐射通量≤35 kW/m2)：产生的炭层基本未破裂；(b)区域2(35 kW/m2外加热辐射通量≤45 kW/m2)：产生的炭层部分破裂：(c)区域3(外加热辐射通量45 kW/m2)：产生的炭层完全破裂。处于区域2及3的试样的热分解过程可分为6个阶段：点燃前的初级分解阶段(阶段Ⅰ)、点燃后的加速分解阶段(阶段Ⅱ)、产生大量炭层的分解减弱阶段(阶段Ⅲ)、炭层破裂后的进一步分解阶段(阶段Ⅳ)、产生少量炭层的第二次分解减弱阶段(阶段V)及无焰氧化阶段(阶段Ⅵ)。然而处于区域1的试样的热分解过程中仅仅存在4个阶段(其中阶段Ⅳ及Ⅴ消失)。当外加热辐射通量大于35 kW/m2时,热释放速率(HRR)曲线上出现了两个峰值,并且在两个峰之间出现了一个准稳态阶段,同时有效燃烧热(EHC)曲线上也出现了两个峰值,而且EHC曲线上的第二个峰值大于第一个峰值。变换的点燃时间、质量损失速率(MLR)的峰值和平均值、HRR的峰值和平均值、准稳态阶段的HRR以及火灾增长系数(FGI)都随着外加热辐射通量的增加而线性增加。当外加热辐射通量从25kW/m2升高到50 kW/m2时,总释热量线性增大。当外加热辐射通量处于50、55、60和65 kW/m2时,总释热量基本保持不变。热穿透厚度随密度与外加热辐射通量的比值的增大而线性增大。(2)对于酚醛树脂玻璃钢而言,其热分解过程同样可分为6个阶段：点燃前的初级分解阶段(阶段Ⅰ)、点燃后的加速分解阶段(阶段Ⅱ)、产生大量炭层的分解减弱阶段(阶段Ⅲ)、炭层破裂后的进一步分解阶段(阶段Ⅳ)、产生少量炭层的第二次分解减弱阶段(阶段V)及无焰氧化阶段(阶段Ⅵ)。点燃时间随着试样厚度的增加而增大。随着外加热辐射通量的增加,不同厚度的试样的点燃时间的差异缩小。随着试样厚度的增加,质量损失系数减小,然而平均MLR增大。MLR曲线上出现了两个峰值。3mm厚的试样的平均HRR大于5 mm厚的试样的平均HRR,8 mm厚的试样的平均HRR在这三者当中是最大的。随着试样厚度的增大,总释热量也随之增加。随着外加热辐射通量的增大,变换的点燃时间、MLR的峰值和平均值、HRR的最大值和平均值及FGI都随之线性增加。随着密度和外加热辐射通量比值的增加,热穿透厚度也随之线性增大。获得并验证了阻燃三元乙丙橡胶及酚醛树脂玻璃钢的燃烧特性参数：基于锥形量热仪特征参数与外加热辐射通量之间的关系,并结合理论分析,推理得到了阻燃三元乙丙橡胶及酚醛树脂玻璃钢的燃烧特性参数,包括临界热辐射通量、最小热辐射通量、点燃温度、汽化潜热及燃烧热,并对其正确性进行了验证。
[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.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：U231.96;U270.4;TQ038
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本文编号：2232638
[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.
【学位授予单位】：中国科学技术大学
【学位级别】：博士
【学位授予年份】：2016
【分类号】：U231.96;U270.4;TQ038
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本文编号：2232638
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