【摘要】：隨著現(xiàn)代化工生產(chǎn)企業(yè)的快速發(fā)展,因可燃?xì)怏w泄漏導(dǎo)致的重大安全生產(chǎn)事故頻繁發(fā)生,可燃?xì)怏w的爆炸往往會(huì)直接致使重大的傷亡事故和財(cái)產(chǎn)損失,其中重要的原因之一就是對可燃?xì)怏w發(fā)生爆炸的機(jī)理和規(guī)律的研究不夠充分,導(dǎo)致在突發(fā)事件發(fā)生后,防爆和抑爆裝置未能起到很好的效果。目前為止,許多學(xué)者針對可燃?xì)怏w的爆炸已經(jīng)展開了比較深入的研究和探索,然而由于其爆炸的危險(xiǎn)性和復(fù)雜性,對其不同條件下發(fā)生爆炸的規(guī)律研究仍然是該領(lǐng)域研究的熱點(diǎn)和難點(diǎn)。計(jì)算機(jī)的快速發(fā)展為研究可燃?xì)庠频谋ㄌ峁┝烁啾憷臈l件,尤其是CFD數(shù)值模擬方法的普遍應(yīng)用。本文研究是在充分學(xué)習(xí)了解可燃?xì)怏w爆炸的理論基礎(chǔ)之上,并且借鑒相關(guān)研究成果,基于流體力學(xué)控制方程組、Realizablek-ε湍流方程和Eddy-Dissipation燃燒模型,建立了可燃?xì)庠票嫉睦碚撃Ｐ?對半徑為0.5m的半球形乙炔-空氣預(yù)混氣云爆炸進(jìn)行了三維數(shù)值模擬,并采用了密度基耦合求解器進(jìn)行了數(shù)值求解,研究了爆炸超壓隨著時(shí)間變化的分布規(guī)律、最大超壓與爆心距離的關(guān)系以及可燃?xì)庠迫剂蠞舛葘Ρǔ瑝旱挠绊?并把數(shù)值模擬結(jié)果與實(shí)驗(yàn)值進(jìn)行了分析比較。論文選取了乙炔質(zhì)量分?jǐn)?shù)分別為5.3%、10.4%、13.3%和15.4%的預(yù)混氣體,并得到不同質(zhì)量分?jǐn)?shù)的混合氣云爆炸超壓沿時(shí)間與空間的分布,模擬得到最大爆炸壓力與實(shí)驗(yàn)結(jié)果吻合良好,最大相對偏差為13.79%;乙炔-空氣爆炸的最危險(xiǎn)質(zhì)量分?jǐn)?shù)為13.3%,其大約為化學(xué)計(jì)量比濃度的1.1倍,在這個(gè)濃度下,爆燃強(qiáng)度最大,同時(shí)破壞力也最嚴(yán)重;在氣云爆炸初期,爆炸壓力急劇增加,達(dá)到最大爆炸壓力,在短期內(nèi)有周期性的超壓波不斷向外擴(kuò)散,且當(dāng)氣體濃度處于最危險(xiǎn)質(zhì)量分?jǐn)?shù)時(shí),產(chǎn)生的爆炸壓力最大。在工業(yè)生產(chǎn)中,應(yīng)盡量避免氣體濃度達(dá)到其最危險(xiǎn)質(zhì)量分?jǐn)?shù),從而預(yù)防事故的發(fā)生�；诮⒌目扇�?xì)庠票〝?shù)值模型,進(jìn)一步在開敞空間內(nèi)放置障礙物,即在障礙物的誘導(dǎo)下,會(huì)產(chǎn)生極大破壞力的爆炸。因此,本文研究了有障礙物約束條件下對可燃?xì)庠票▓龅挠绊?為提出可行的防爆、抑爆方案提供理論依據(jù)和數(shù)據(jù)支持。本文通過對內(nèi)置障礙物條件下乙炔-空氣爆炸進(jìn)行了數(shù)值模擬,分析了障礙物對爆炸超壓產(chǎn)生的加速機(jī)理、距點(diǎn)火源不同距離的障礙物對爆燃強(qiáng)度的影響以及障礙物的數(shù)量對爆炸超壓的影響。通過研究得出,同一測點(diǎn),相比無障礙物時(shí),達(dá)到峰值超壓的時(shí)間明顯縮短,且最大爆炸壓力大約為無障礙物時(shí)的6~8倍,最大爆炸壓力可達(dá)25.33KPa,障礙物對爆炸超壓具有較強(qiáng)的加強(qiáng)作用,可造成建筑物的嚴(yán)重破壞;當(dāng)障礙物在氣云內(nèi)部時(shí),可燃?xì)庠票óa(chǎn)生的峰值超壓隨著障礙物與點(diǎn)火源距離的增加而增加;當(dāng)障礙物在可燃?xì)庠仆獠繒r(shí),峰值超壓逐漸有減小的趨勢;可燃?xì)怏w爆炸超壓與障礙物數(shù)量呈正比,也就是隨著障礙物數(shù)量的增加,障礙物對爆炸沖擊波阻礙的程度就越大,則湍流程度越大,會(huì)產(chǎn)生更大的爆炸威力。
[Abstract]:With the rapid development of modern chemical production enterprises, serious accidents in production safety caused by the leakage of combustible gases occur frequently, and the explosion of combustible gases often directly results in serious casualties and property losses. One of the important reasons is that the research on the mechanism and laws of the explosion of combustible gases is insufficient. Up to now, many scholars have carried out in-depth research and Exploration on the explosion of combustible gases. However, because of the danger and complexity of explosion, the research on the law of explosion under different conditions is still a hot topic in this field. The rapid development of computer provides more convenient conditions for studying the explosion of combustible gas clouds, especially the universal application of CFD numerical simulation method. The flow equation and Eddy-Dissipation combustion model were used to establish the theoretical model of flammable cloud deflagration. The explosion of hemispherical acetylene-air premixed cloud with radius of 0.5m was numerically simulated in three dimensions. The density-based coupling solver was used to solve the problem. The distribution of explosive overpressure with time, the maximum overpressure and the maximum overpressure were studied. The relationship between detonation center distance and the influence of fuel concentration of combustible gas cloud on the explosion overpressure are analyzed and compared with the experimental results. The maximum explosion pressure obtained by simulation is in good agreement with the experimental results, the maximum relative deviation is 13.79%; the most dangerous mass fraction of acetylene-air explosion is 13.3%, which is about 1.1 times of the stoichiometric specific concentration. At this concentration, the detonation intensity is the largest and the destructive force is the most serious; at the initial stage of gas cloud explosion, the explosion pressure increases sharply, reaching to 13.3%. When the gas concentration is in the most dangerous mass fraction, the explosion pressure is the highest. In industrial production, the gas concentration should be avoided to reach the most dangerous mass fraction as far as possible, so as to prevent the occurrence of accidents. In this paper, the influence of obstacles on the explosion field of combustible clouds is studied, which provides theoretical basis and data support for putting forward feasible explosion-proof and explosion-suppression schemes. Acetylene-air explosion was simulated numerically. The acceleration mechanism of explosion overpressure caused by obstacles, the effect of obstacles at different distances from ignition source on detonation intensity and the influence of obstacles on Explosion Overpressure were analyzed. The maximum explosion pressure can reach 25.33 KPa. Obstacles can strengthen the explosion overpressure and cause serious damage to buildings. When the obstacles are inside the gas cloud, the peak overpressure caused by the explosion of combustible cloud increases with the distance between the obstacles and the ignition source. Additionally, when the obstacle is outside the combustible cloud, the peak overpressure decreases gradually, and the explosive overpressure of combustible gas is proportional to the number of obstacles, that is, with the increase of the number of obstacles, the obstacle hinders the explosive shock wave to a greater extent, the greater the turbulence flow, will produce greater explosive power.
【學(xué)位授予單位】：天津理工大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：X928.7

【相似文獻(xiàn)】

相關(guān)碩士學(xué)位論文 前1條

1 黨福輝;開敞空間可燃?xì)庠票〝?shù)值模擬研究[D];天津理工大學(xué);2017年

，

本文編號：2212926