本文選題：云團爆炸　切入點：內(nèi)置結(jié)構(gòu)　出處：《北京理工大學》2016年碩士論文　論文類型：學位論文

【摘要】：可燃氣云爆炸是工業(yè)生產(chǎn)和生活領(lǐng)域爆炸災(zāi)害的主要形式之一,內(nèi)置結(jié)構(gòu)在云團爆炸中的作用非常復雜,氣體在爆炸過程中的流動性更增加了氣云爆炸的復雜性,科學的認識可燃氣云爆炸及其流動性耦合規(guī)律是有效預防和控制爆炸事故亟待解決的關(guān)鍵課題。本文以甲烷/空氣、丙烷/空氣、氫氣/空氣云團為研究對象,運用數(shù)值計算對無約束云團爆炸及其流動耦合規(guī)律展開研究,探索了云團內(nèi)置結(jié)構(gòu)、濃度、體積及氣體活性對爆炸物理特征的影響規(guī)律,主要工作和創(chuàng)新性成果如下:一、內(nèi)置結(jié)構(gòu)對云團爆炸特性的影響規(guī)律揭示了內(nèi)置結(jié)構(gòu)影響氣云爆炸過程的雙重特征,內(nèi)置結(jié)構(gòu)阻塞比及其空間分布對氣云爆炸參數(shù)具有同樣重要作用。在內(nèi)置結(jié)構(gòu)的空間分布一定時,氣云爆炸參數(shù)在某一阻塞比下取得最大值;在障礙物阻塞比一定時,內(nèi)置障礙物越稠密,氣云爆炸參數(shù)越大。在本文計算條件下,障礙物空間分布為8 x 8 x 4時,甲烷/空氣云團爆炸參數(shù)在阻塞比為0.74時取得最大值;障礙物阻塞比為3.07時,甲烷/空氣云團爆炸參數(shù)隨著障礙物排列變得稠密,爆炸參數(shù)逐漸增大。研究發(fā)現(xiàn),動壓量級可達104 Pa,同樣具有強大的破壞作用,另外燃燒區(qū)大于初始預混區(qū),燃燒區(qū)大小主要受障礙物阻塞比影響,阻塞比越大,燃燒區(qū)越小。二、云團爆炸沖擊波與高溫流動的耦合規(guī)律揭示了氣云爆炸沖擊波和高溫流動在時間和空間上的耦合規(guī)律,內(nèi)置結(jié)構(gòu)的空間分布一定時,隨著阻塞比增大,兩者峰值間的時差間隔先減小后增大,在某一阻塞比下取得最小值;阻塞比一定時,障礙物排列越稠密,兩者峰值間的時差間隔越小。在本文計算條件下,障礙物空間分布為8 x 8 x 4時,兩者峰值間的時差間隔隨著阻塞比增大先減小后增大,在阻塞比為0.74時取得最小值;障礙物阻塞比為3.07時,隨著障礙物排列變得稠密,兩者間時差間隔逐漸減小。三、不同濃度云團爆炸的物理特性本文對貧燃料和富燃料濃度甲烷/空氣云團爆炸進行數(shù)值模擬,發(fā)現(xiàn)不同濃度甲烷/空氣云團爆炸超壓的衰減趨勢不完全相同,富燃料濃度云團爆炸超壓在一定條件下會出現(xiàn)壓力突升,貧燃料濃度時,當障礙物密度足夠大時在障礙物區(qū)邊界處會出現(xiàn)壓力上升。不同濃度的燃燒率衰減趨勢也不完全相同,化學計量濃度和7%貧燃料濃度的燃燒率隨著距離變化單調(diào)遞減,而12%富燃料濃度時在衰減階段再次出現(xiàn)燃燒率增大。四、云團爆炸的體積效應(yīng)及規(guī)律揭示了云團爆炸特性的體積效應(yīng),溫度場分布體積效應(yīng)顯著,化學計量濃度和貧燃料濃度時,云團體積越大,無量綱穩(wěn)定高溫區(qū)域越大;富燃料濃度時,云團體積越大,無量綱穩(wěn)定高溫區(qū)域越小�；鹧鎱^(qū)分布同樣具有明顯體積效應(yīng),化學計量濃度時,無量綱火焰區(qū)域隨云團體積增大逐漸增大,7%貧燃料時不同體積云團爆炸的無量綱火焰區(qū)域基本相同,12%富燃料濃度時無量綱火焰區(qū)域隨云團體積增大逐漸減小。氣云爆炸效應(yīng)的幾何相似不再成立,爆炸參數(shù)與無量綱距離的關(guān)系與云團的體積相關(guān),隨著云團體積增大,相同無量綱距離處的爆炸超壓、動壓和燃燒率均增大,而溫度場分布略有不同,貧燃料和化學計量濃度的爆炸溫度隨著云團體積增大逐漸增大,富燃料濃度時爆炸溫度隨云團體積增大逐漸減小。
[Abstract]:Flammable gas explosion is one of the main forms of the field of industrial production and life explosion disasters, in structure in the cloud explosion in very complex, liquidity in the process of explosion gas increases the complexity of gas explosion, scientific understanding of flammable gas explosion and its flow coupling rule is a key issue for effective prevention and the explosion control needs to be solved. In this paper, methane / air, propane / air and hydrogen / air cloud as the research object, the calculation of unconstrained cloud explosion and its flow is studied by numerical coupling law, explore the cloud internal structure, concentration, influence of volume and gas explosion on the activity of physical characteristics, the main work and the innovative results are as follows: first, effect of internal structure on cloud explosion characteristics reveals the dual characteristics of internal structure affect the explosion process of gas cloud, built-in structure and blocking The spatial distribution of explosion parameters also play an important role on the gas cloud. In the spatial distribution of a built-in structure, gas cloud explosion parameters in a blocking ratio reached the maximum value; in the blockage ratio, built-in obstacles more dense gas cloud explosion parameter is large. In this paper calculation conditions, obstacles the spatial distribution of 8 x 8 x 4, methane / air cloud explosion parameters in the blocking ratio of 0.74 has a maximum value; the blockage ratio is 3.07, the methane / air cloud explosion parameters with obstacle arrangement becomes dense, the explosion parameter increases. The study found that the dynamic pressure magnitude can reach 104 Pa also has strong destructive effect, in addition to the combustion zone is greater than the initial pre mixing zone, combustion zone is mainly controlled by the blockage ratio, blocking ratio is larger, the smaller area of combustion. Two, cloud explosion shock wave and high temperature flow coupling law reveals the gas cloud The coupled flow law of explosion shock wave and high temperature in time and space, the space distribution of a built-in structure, with the blocking ratio increases, the peak time interval between the first decreases and then increases at a blockage ratios has a minimum value; blocking ratio, obstacle arrangement more dense, time interval between the two the peak between the smaller calculation conditions. In this paper, the obstacle space distribution of 8 x 8 x 4, two peak between the time interval with the blocking ratio first decreases and then increases, the blocking ratio of 0.74 is the minimum; the blockage ratio is 3.07, the obstacles are become dense between the time interval decreased gradually. Three, the physical properties of different concentrations of cloud explosion fuel lean and rich fuel concentration of methane / air cloud explosion numerical simulation, found that the attenuation trend of different concentrations of methane / air cloud explosion overpressure Not exactly the same, the fuel rich concentration of cloud explosion overpressure in certain conditions will appear under the pressure rise, lean fuel concentration, when the obstacle density is large enough in the boundary obstacles occur at different concentrations. The combustion pressure rise rate attenuation trend is not exactly the same, the stoichiometric concentration and 7% lean fuel concentration the burning rate with decreasing distance changes and monotonous, 12% fuel rich concentration in the decay phase again burning rate increases. Four, volume effect and regularity of cloud explosion reveals the volume effect of cloud explosion characteristics, temperature field distribution volume effect significantly, concentration of stoichiometric concentration and poor fuel, the cloud volume is large, no the dimensional stability of high temperature area is larger; the fuel rich concentration, the cloud volume is large, the dimensionless stability in high temperature region. The smaller the flame zone distribution also has obvious volume effect, the stoichiometric concentration, the dimensionless fire The flame area gradually increases with the increase of the cloud volume, the dimensionless flame region 7% lean fuel when the different volume of cloud explosion is basically the same, 12% dimensionless concentration of fuel rich flame region with the cloud volume decreases with increasing of gas cloud explosion effect. The geometric similarity is no longer valid, the explosion parameters and the dimensionless distance relationship with the cloud volume related with the cloud volume increases, the same dimensionless distance of explosion overpressure, dynamic pressure and combustion rate are increased, the temperature distribution is slightly different, the fuel lean and stoichiometric concentration with increasing volume of cloud explosion temperature gradually increased, when the concentration of the fuel rich explosion temperature with cloud volume increases gradually decreases.

【學位授予單位】：北京理工大學
【學位級別】：碩士
【學位授予年份】：2016
【分類號】：X932

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