典型有機(jī)保溫材料的熱過(guò)程演化及火蔓延特性研究
發(fā)布時(shí)間：2018-08-28 13:35
【摘要】：建筑節(jié)能是建設(shè)低耗環(huán)保型社會(huì)和保持經(jīng)濟(jì)可持續(xù)發(fā)展的關(guān)鍵環(huán)節(jié)。有機(jī)保溫材料因?yàn)槠鋬?yōu)越的隔熱效果而被國(guó)內(nèi)外的建筑保溫系統(tǒng)廣泛采用,其中熱塑性材料和熱固性材料作為日常生活中最常見(jiàn)的有機(jī)保溫材料,應(yīng)用極為廣泛。然而,這些材料在受熱情況下易產(chǎn)生裂解甚至發(fā)生燃燒,火蔓延速度極快,同時(shí)會(huì)產(chǎn)生大量的煙氣和有毒有害氣體。對(duì)于外墻保溫材料的熱危害性的防治已經(jīng)成為大力發(fā)展節(jié)能型建筑急需解決的關(guān)鍵問(wèn)題。不同于熱固性材料的燃燒行為,熱塑性保溫材料燃燒過(guò)程中會(huì)產(chǎn)生大量的熔融滴落物質(zhì),并且在壁面火蔓延的底部積聚形成流淌油池火,加大其整體熱危害性。本文選取最常見(jiàn)的三種熱塑性材料：聚乙烯(PE),聚丙烯(PP)和聚苯乙烯(PS)作為實(shí)驗(yàn)研究對(duì)象,并通過(guò)自行搭建的實(shí)驗(yàn)平臺(tái),開(kāi)展一系列實(shí)驗(yàn)。觀察分析三種熱塑性顆粒材料形成穩(wěn)定熔融滴落熔液情況下,產(chǎn)生的油池火蔓延流淌行為,并且定量分析不同逆向滴落速率下情況下油池火的流淌速率,溫度場(chǎng),輻射場(chǎng)和質(zhì)量變化等規(guī)律。本文圍繞三種典型熱塑性材料熔融滴落形成的油池火所進(jìn)行的實(shí)驗(yàn)研究和理論分析表明,三種熱塑性材料加熱后形成的熔融物質(zhì)在空中滴落過(guò)程中的質(zhì)量損失占整體質(zhì)量損失相當(dāng)大的比例,高溫熔液在空中逆向滴落過(guò)程中的熱量損失同樣會(huì)對(duì)周圍環(huán)境形成較大熱危害,增加消防撲救的難度。相同條件下,聚苯乙烯(PS)形成的高溫熔融液滴由于其較大的粘性導(dǎo)致其逆向滴落速率低于聚丙烯(PP)和聚乙烯(PE)。由于三種熱塑性材料解聚物表觀粘性和材料分子結(jié)構(gòu)的差異,導(dǎo)致聚苯乙烯(PS)形成的油池火流淌速率慢于聚丙烯(PP)和聚乙烯(PE),但聚苯乙烯(PS)形成的熔滴油池火在熔流槽內(nèi)流淌蔓延過(guò)程中的燃燒速率卻高于聚丙烯(PP)和聚乙烯(PE),聚苯乙烯材料較大的燃燒熱及流淌粘度使得其形成的流淌火火焰前鋒和油池的前鋒移動(dòng)保持一致。從熔融、滴落和流淌三方面特性觀察熱塑性材料表現(xiàn)出的燃燒行為差異,聚丙烯(PP)和聚乙烯(PE)形成的滴落流淌火熱危害性大于聚苯乙烯(PS)。所以在實(shí)際的建筑防火設(shè)計(jì)中,對(duì)熱塑性材料火災(zāi)熱危害性的綜合性評(píng)估是非常必要且關(guān)鍵的。另一方面,熱固性保溫材料的火蔓延行為是氣相燃燒與固相熱解相互耦合的復(fù)雜反應(yīng)過(guò)程。本文選取典型熱固性保溫材料—硬質(zhì)聚氨酯泡沫(RPU)和軟質(zhì)聚氨酯泡沫(FPU)作為研究對(duì)象,通過(guò)外加輻射源,模擬研究實(shí)際火災(zāi)場(chǎng)景中不同的外界輻射強(qiáng)度下二種保溫材料的火蔓延行為,著重分析火蔓延速度、溫度場(chǎng)、質(zhì)量損失、火焰脈動(dòng)頻率和火焰高度等典型特征參數(shù)隨試樣寬度的變化規(guī)律。存在外界輻射源情況較之普通環(huán)境的逆向穩(wěn)態(tài)火蔓延過(guò)程具有更強(qiáng)的輻射熱反饋,硬質(zhì)聚氨酯(RPU)和軟質(zhì)聚氨酯(FPU)板材的逆向火蔓延皆會(huì)發(fā)生加速蔓延現(xiàn)象,板材表面火蔓延隨著外界輻射強(qiáng)度的增加,會(huì)產(chǎn)生大量熱解氣,加劇火勢(shì),質(zhì)量損失速率和火蔓延速度與外界輻射強(qiáng)度大小呈正相關(guān)的關(guān)系。相比硬質(zhì)聚氨酯(RPU)材料,軟質(zhì)聚氨酯(FPU)泡沫由于其自身的物理結(jié)構(gòu),表現(xiàn)出了更充分的燃燒性能。當(dāng)外界輻射強(qiáng)度大于一定強(qiáng)度時(shí),硬質(zhì)聚氨酯材料沿厚度方向?qū)⒈煌耆纪�。而二者的火焰高度的變化�?guī)律則是無(wú)關(guān),主要受輻射強(qiáng)度控制。硬質(zhì)聚氨酯和軟質(zhì)聚氨酯板材的火焰脈動(dòng)頻率與外界輻射強(qiáng)度和寬度耦合作用的結(jié)果。當(dāng)外界輻射強(qiáng)度較小時(shí),硬質(zhì)聚氨酯板材的火焰高度隨著板材寬度的增加而增加；反之,火焰高度的增加與板材寬度外界輻射強(qiáng)度和寬度呈反相關(guān)關(guān)系。由于軟質(zhì)聚氨酯板材燃燒過(guò)程中火焰前鋒出會(huì)出現(xiàn)一層薄熔融層,我們借鑒油池火理論對(duì)軟質(zhì)聚氨酯的火焰脈動(dòng)頻率和火焰高度進(jìn)行預(yù)測(cè),得出的實(shí)驗(yàn)數(shù)據(jù)變化趨勢(shì)與理論公式預(yù)測(cè)曲線表現(xiàn)出很好的一致性。
[Abstract]:Building energy conservation is the key link of building a low-consumption environment-friendly society and maintaining sustainable economic development.Organic thermal insulation materials are widely used in building thermal insulation systems at home and abroad because of their superior thermal insulation effect.Thermoplastic materials and thermosetting materials are the most common organic thermal insulation materials in daily life. However, these materials are liable to crack or even burn under the condition of being heated, and fire spreads very fast. At the same time, a lot of flue gas and poisonous and harmful gases are produced. Thermoplastic insulation materials produce a large number of melt dropping substances during the combustion process, and accumulate at the bottom of the spread of wall fire to form flowing oil pool fire, increasing its overall thermal hazard. A series of experiments were carried out on the experimental platform. The spreading and flowing behavior of pool fire was observed and analyzed when three kinds of thermoplastic granular materials formed stable dropping melt. The flow rate, temperature field, radiation field and mass change of pool fire under different reverse dropping rates were quantitatively analyzed. Experimental study and theoretical analysis of pool fire formed by melt dropping of typical thermoplastic materials show that the mass loss of melt formed by three thermoplastic materials in the process of air dropping accounts for a considerable proportion of the total mass loss, and the heat loss of high temperature melt in the process of air reverse dropping will also be around. Under the same conditions, the high-temperature melt droplets formed by polystyrene (PS) have a lower reverse dripping rate than polypropylene (PP) and polyethylene (PE) due to their greater viscosity. Due to the difference of the apparent viscosity and the molecular structure of the three thermoplastic materials, polyphenylethylene (PP) is produced. The flow rate of pool fire formed by polystyrene (PS) is slower than that of polypropylene (PP) and polyethylene (PE), but the combustion rate of pool fire formed by polystyrene (PS) is higher than that of polypropylene (PP) and polyethylene (PE) during the flow and spread process in the pool. The higher combustion heat and viscosity of polystyrene make the flame front and flame front formed by the pool fire. The difference of combustion behavior of thermoplastic materials was observed from three aspects of melting, dropping and flowing characteristics. The thermal hazard of dropping flow formed by polypropylene (PP) and polyethylene (PE) was greater than that of polystyrene (PS). Therefore, the thermal hazard of thermoplastic materials in fire protection design was synthesized. On the other hand, the fire spread behavior of thermosetting insulation materials is a complex reaction process coupled with gas-phase combustion and solid-phase pyrolysis. In this paper, the typical thermosetting insulation materials, rigid polyurethane foam (RPU) and soft polyurethane foam (FPU), are selected as the research objects and simulated by external radiation sources. The fire spread behavior of two kinds of insulation materials under different external radiation intensity in actual fire scene is studied. The variation of typical characteristic parameters such as fire spread velocity, temperature field, mass loss, flame fluctuation frequency and flame height with sample width is analyzed emphatically. The process has stronger radiation heat feedback. The reverse fire spread of rigid polyurethane (RPU) and flexible polyurethane (FPU) sheets will accelerate. With the increase of external radiation intensity, a large amount of pyrolysis gas will be produced, which will aggravate the fire. The mass loss rate and fire spread speed are positive with the external radiation intensity. The results show that flexible polyurethane (FPU) foams exhibit better combustibility than rigid polyurethane (RPU) foams because of their own physical structure. When the external radiation intensity is greater than a certain intensity, rigid polyurethane materials will be fully burned along the thickness direction. However, the flame height of the two foams is independent, mainly. Controlled by radiation intensity, the flame fluctuation frequency of rigid polyurethane and flexible polyurethane sheets is coupled with external radiation intensity and width. When external radiation intensity is small, the flame height of rigid polyurethane sheets increases with the increase of plate width; otherwise, the flame height increases with the increase of plate width and the external radiation is strong. The flame front appears a thin melting layer during the combustion of soft polyurethane sheet. We use the oil pool fire theory for reference to predict the flame fluctuation frequency and flame height of soft polyurethane. The experimental data show a good consistency with the theoretical prediction curve.
【學(xué)位授予單位】：中國(guó)科學(xué)技術(shù)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU551
本文編號(hào)：2209540
[Abstract]:Building energy conservation is the key link of building a low-consumption environment-friendly society and maintaining sustainable economic development.Organic thermal insulation materials are widely used in building thermal insulation systems at home and abroad because of their superior thermal insulation effect.Thermoplastic materials and thermosetting materials are the most common organic thermal insulation materials in daily life. However, these materials are liable to crack or even burn under the condition of being heated, and fire spreads very fast. At the same time, a lot of flue gas and poisonous and harmful gases are produced. Thermoplastic insulation materials produce a large number of melt dropping substances during the combustion process, and accumulate at the bottom of the spread of wall fire to form flowing oil pool fire, increasing its overall thermal hazard. A series of experiments were carried out on the experimental platform. The spreading and flowing behavior of pool fire was observed and analyzed when three kinds of thermoplastic granular materials formed stable dropping melt. The flow rate, temperature field, radiation field and mass change of pool fire under different reverse dropping rates were quantitatively analyzed. Experimental study and theoretical analysis of pool fire formed by melt dropping of typical thermoplastic materials show that the mass loss of melt formed by three thermoplastic materials in the process of air dropping accounts for a considerable proportion of the total mass loss, and the heat loss of high temperature melt in the process of air reverse dropping will also be around. Under the same conditions, the high-temperature melt droplets formed by polystyrene (PS) have a lower reverse dripping rate than polypropylene (PP) and polyethylene (PE) due to their greater viscosity. Due to the difference of the apparent viscosity and the molecular structure of the three thermoplastic materials, polyphenylethylene (PP) is produced. The flow rate of pool fire formed by polystyrene (PS) is slower than that of polypropylene (PP) and polyethylene (PE), but the combustion rate of pool fire formed by polystyrene (PS) is higher than that of polypropylene (PP) and polyethylene (PE) during the flow and spread process in the pool. The higher combustion heat and viscosity of polystyrene make the flame front and flame front formed by the pool fire. The difference of combustion behavior of thermoplastic materials was observed from three aspects of melting, dropping and flowing characteristics. The thermal hazard of dropping flow formed by polypropylene (PP) and polyethylene (PE) was greater than that of polystyrene (PS). Therefore, the thermal hazard of thermoplastic materials in fire protection design was synthesized. On the other hand, the fire spread behavior of thermosetting insulation materials is a complex reaction process coupled with gas-phase combustion and solid-phase pyrolysis. In this paper, the typical thermosetting insulation materials, rigid polyurethane foam (RPU) and soft polyurethane foam (FPU), are selected as the research objects and simulated by external radiation sources. The fire spread behavior of two kinds of insulation materials under different external radiation intensity in actual fire scene is studied. The variation of typical characteristic parameters such as fire spread velocity, temperature field, mass loss, flame fluctuation frequency and flame height with sample width is analyzed emphatically. The process has stronger radiation heat feedback. The reverse fire spread of rigid polyurethane (RPU) and flexible polyurethane (FPU) sheets will accelerate. With the increase of external radiation intensity, a large amount of pyrolysis gas will be produced, which will aggravate the fire. The mass loss rate and fire spread speed are positive with the external radiation intensity. The results show that flexible polyurethane (FPU) foams exhibit better combustibility than rigid polyurethane (RPU) foams because of their own physical structure. When the external radiation intensity is greater than a certain intensity, rigid polyurethane materials will be fully burned along the thickness direction. However, the flame height of the two foams is independent, mainly. Controlled by radiation intensity, the flame fluctuation frequency of rigid polyurethane and flexible polyurethane sheets is coupled with external radiation intensity and width. When external radiation intensity is small, the flame height of rigid polyurethane sheets increases with the increase of plate width; otherwise, the flame height increases with the increase of plate width and the external radiation is strong. The flame front appears a thin melting layer during the combustion of soft polyurethane sheet. We use the oil pool fire theory for reference to predict the flame fluctuation frequency and flame height of soft polyurethane. The experimental data show a good consistency with the theoretical prediction curve.
【學(xué)位授予單位】：中國(guó)科學(xué)技術(shù)大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU551
【參考文獻(xiàn)】
相關(guān)期刊論文 前1條
1 鄒樣輝,周建軍,鐘占榮,范維澄;外加輻射條件下水平方向火蔓延的實(shí)驗(yàn)研究[J];中國(guó)科學(xué)技術(shù)大學(xué)學(xué)報(bào);2001年04期
，本文編號(hào)：2209540
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