【摘要】：煙氣是建筑火災(zāi)中造成人員傷亡的主要原因,煙氣的流動(dòng)特性成為建筑防火設(shè)計(jì)中的研究熱點(diǎn)。建筑火災(zāi)發(fā)生后,高層建筑中諸多豎井產(chǎn)生的“煙囪效應(yīng)”是煙氣豎向運(yùn)動(dòng)的主要驅(qū)動(dòng)力,煙氣進(jìn)入豎井后通過(guò)開(kāi)口或縫隙侵入樓層區(qū)域,從而造成煙氣的蔓延�？紤]到建筑豎井產(chǎn)生的“煙囪效應(yīng)”,結(jié)合火災(zāi)煙氣數(shù)值模擬的方法,對(duì)高層建筑利用電梯豎井的排煙系統(tǒng)進(jìn)行分析研究。鑒于建筑豎井產(chǎn)生的“煙囪效應(yīng)”,可以考慮利用建筑豎井進(jìn)行排煙。遵循火災(zāi)煙氣從高壓區(qū)向低壓區(qū)流動(dòng)的規(guī)律,針對(duì)高層建筑中電梯豎井與樓梯豎井分開(kāi)設(shè)置的情況,本文提出了高層建筑利用電梯豎井進(jìn)行排煙的研究課題。《高層民用建筑設(shè)計(jì)防火規(guī)范》(GB50045-2005)8.1條中提到了可利用建筑豎井有組織地自然排煙,但建筑豎井占地面積較大,一般情況下設(shè)計(jì)者很難接受,所以近年來(lái)很少采用。電梯豎井是一個(gè)將整棟建筑物上下連接的通道,截面積較大,具有作為排煙豎井的可能性。從實(shí)踐上看,若將消防樓梯間與電梯間作平面分離,分別作為人員逃生和火災(zāi)煙氣排出的通道,則可以考慮在電梯豎井頂部設(shè)置排煙口進(jìn)行排煙。《高層民用建筑設(shè)計(jì)防火規(guī)范》尚未明確規(guī)定針對(duì)電梯豎井具體的防排煙措施,本文主要針對(duì)高層建筑利用電梯豎井的排煙系統(tǒng)進(jìn)行研究。在數(shù)學(xué)模型研究方面,主要利用網(wǎng)絡(luò)模型對(duì)高層建筑火災(zāi)煙氣的流動(dòng)規(guī)律進(jìn)行數(shù)值計(jì)算。傳統(tǒng)的網(wǎng)絡(luò)模型對(duì)著火房間火災(zāi)過(guò)程的處理比較簡(jiǎn)單,未考慮煙氣與壁面的換熱,且忽略了煙氣流動(dòng)摩擦阻力損失,計(jì)算結(jié)果勢(shì)必與實(shí)際火災(zāi)煙氣流動(dòng)規(guī)律相差較大。基于傳統(tǒng)網(wǎng)絡(luò)模型,提出一種改良的網(wǎng)絡(luò)模型：在著火房間采用雙區(qū)模型；考慮了火災(zāi)煙氣與建筑豎井壁面之間的對(duì)流換熱與輻射換熱；考慮了火災(zāi)煙氣在建筑豎井內(nèi)的流動(dòng)摩擦阻力損失,以修正豎井煙氣上升阻力及豎井排煙能力。在模型驗(yàn)證方面,對(duì)改良的網(wǎng)絡(luò)模型中各子模型的準(zhǔn)確性進(jìn)行驗(yàn)證：所編寫(xiě)傳統(tǒng)網(wǎng)絡(luò)模型與著火房間雙區(qū)模型程序分別與CONTAM軟件、FDS (Fire Dynamic Simulator)軟件的計(jì)算結(jié)果進(jìn)行對(duì)比；對(duì)豎井內(nèi)煙氣的傳熱進(jìn)行了縮尺模型實(shí)驗(yàn),并采用鹽水模型實(shí)驗(yàn)對(duì)豎井內(nèi)的煙氣流動(dòng)進(jìn)行了直觀演示。基于上述各子模型建立的改良網(wǎng)絡(luò)數(shù)學(xué)模型及求解方法,為高層建筑火災(zāi)煙氣的流動(dòng)規(guī)律提供了研究手段。在應(yīng)用研究方面,本文利用改良的網(wǎng)絡(luò)模型對(duì)高層建筑利用電梯豎井的自然排煙進(jìn)行了數(shù)值計(jì)算,詳細(xì)分析了電梯豎井頂部開(kāi)口面積、著火層常閉排煙口尺寸、電梯門(mén)縫寬度與豎井壁面摩擦阻力系數(shù)對(duì)電梯豎井自然排煙的影響。在數(shù)值計(jì)算過(guò)程中,防煙樓梯間作為人員逃生通道,采用機(jī)械加壓送風(fēng)方式阻止煙氣侵入,著火層內(nèi)未考慮機(jī)械排煙。為了比較不同工況下的排煙效果,主要考慮電梯豎井中和面位置、電梯豎井排煙量與從著火層進(jìn)入電梯豎井的煙氣量,提出了電梯豎井綜合排煙系數(shù)的概念；利用正交實(shí)驗(yàn)方法得到了各影響因素在計(jì)算范圍內(nèi)的重要程度,并分析了不同著火樓層下利用電梯豎井自然排煙的效果。對(duì)著火層以上各樓層進(jìn)行加壓送風(fēng),利用改良的網(wǎng)絡(luò)模型對(duì)電梯豎井的排煙進(jìn)行數(shù)值計(jì)算,得到了不同的加壓送風(fēng)量對(duì)電梯豎井排煙效果的影響；分析了著火樓層不同時(shí),對(duì)著火層以上各樓層加壓送風(fēng)對(duì)電梯豎井排煙效果的影響。結(jié)合遺傳算法,對(duì)某高層建筑利用電梯豎井排煙進(jìn)行了優(yōu)化計(jì)算,得到了電梯豎井頂部開(kāi)口面積比、加壓送風(fēng)量、電梯門(mén)縫寬度與著火層常閉排煙口尺寸在計(jì)算范圍內(nèi)優(yōu)化,電梯豎井能夠達(dá)到較好的排煙效果。
[Abstract]:The flue gas is the main cause of casualties in building fires, and the flue gas flow characteristics become the research hotspot in building fire protection design. Considering the "chimney effect" produced by building shaft and combining with the method of fire smoke numerical simulation, the smoke exhaust system of elevator shaft in high-rise building is analyzed and studied. According to the law of pressure zone flowing to low pressure zone and the situation that the elevator shaft and the staircase shaft are separated in high-rise buildings, this paper puts forward the research subject of smoke exhaust by elevator shaft in high-rise buildings. The elevator shaft is a passage connecting the whole building up and down, with a large cross-section area, and it is possible to be used as a smoke exhaust shaft. Fire smoke exhaust passage can be considered in the top of the elevator shaft for smoke exhaust. has not clearly defined specific smoke prevention and exhaust measures for elevator shaft, this paper mainly for high-rise buildings using elevator shaft smoke exhaust system. The traditional network model is simple in dealing with the fire process of a high-rise building. It does not consider the heat transfer between the smoke and the wall, and ignores the friction loss of the smoke flow. An improved network model is proposed based on the traditional network model: a two-zone model is used in the fire chamber; the convective and radiative heat transfer between the fire smoke and the wall of the building shaft is considered; and the friction loss of the fire smoke in the building shaft is considered to correct the rising resistance of the shaft smoke and the smoke exhaust capacity of the shaft. In the aspect of model validation, the accuracy of each sub-model in the improved network model is verified: the traditional network model and the two-zone model program of the fire room are compared with the results of CONTAM software and FDS (Fire Dynamic Simulator) software respectively; the scale model experiment of flue gas heat transfer in the shaft is carried out, and salt is used. The water model experiment demonstrates the smoke flow in the shaft directly. The improved network mathematical model and solving method based on the above sub-models provide a research method for the smoke flow law of high-rise building fire. In the aspect of application research, this paper uses the improved network model to study the nature of high-rise building using the elevator shaft. The influence of the opening area at the top of the elevator shaft, the size of the smoke outlet at the normal closure of the fire layer, the width of the elevator door gap and the friction coefficient of the shaft wall on the natural smoke exhaust from the elevator shaft is analyzed in detail. In order to compare the smoke exhaust effect under different working conditions, the position of the neutral plane of the elevator shaft, the smoke exhaust volume of the elevator shaft and the smoke volume from the ignition layer into the elevator shaft were mainly considered, and the concept of the comprehensive smoke exhaust coefficient of the elevator shaft was put forward. The importance of the calculation range is analyzed, and the effect of natural smoke exhaust by elevator shaft under different fire floor is analyzed. The influence of pressurized air supply on the smoke exhaust effect of elevator shaft is studied when the fire floor is different. Combining with genetic algorithm, the smoke exhaust effect of elevator shaft in a high-rise building is optimized. The ratio of the top opening area of elevator shaft, the pressurized air supply rate, the width of elevator door gap and the size of the smoke exhaust nozzle are calculated. Within the scope of optimization, elevator shaft can achieve better smoke exhaust effect.
【學(xué)位授予單位】：華北電力大學(xué)
【學(xué)位級(jí)別】：博士
【學(xué)位授予年份】：2015
【分類(lèi)號(hào)】：TU976.5

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本文編號(hào)：2225974

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