【作者】 李欣；

【导师】 廖才波； 舒胜文；

【作者基本信息】 南昌大学 ， 能源动力（专业学位）， 2023， 硕士

【摘要】 近年来,电力火灾对人民生命和财产安全的威胁不断加重。电缆竖井作为高层建筑中强、弱电传输的重要部分,电缆火灾隐患对其防火及排烟能力提出了较高要求,然而由于“烟囱效应”的作用,竖井内一旦发生火灾,火焰及烟气在垂直方向上将迅速蔓延,对电缆乃至建筑造成极大的危害。本文针对电缆竖井火灾蔓延规律与防火封堵方法开展了相关研究,构建了电缆竖井火灾模型,分析了火源、通风情况、防火材料老化、工艺缺陷和多层封堵等因素对火灾的影响,对不同封堵材料以及阻火包工艺进行了对比研究,并通过试验验证了仿真模型的有效性,最后基于试验分析了不同封堵层结构的防火优劣性。主要包括以下几个方面:(1)首先介绍了电缆竖井火灾的理论基础,采用FDS搭建电缆竖井火灾的仿真模型,针对温度、烟气浓度和热辐射强度等物理量进行了结果分析,探究电缆竖井火灾的发展趋势,以此为基础引出了后续研究工作。(2)从火灾蔓延规律的角度出发,在初始工况的基础上采用控制变量法,分别对火源、通风情况、防火材料老化、工艺缺陷和多层封堵等因素进行相应的影响分析,以火灾时模型内部的烟气浓度、温度和HRR(热释放速率)等物理量为特征量,探究不同影响因素下电缆竖井火灾的蔓延规律,仿真结果表明上述因素对火灾蔓延及竖井内温度分布的影响存在较大差异。(3)从防火封堵的角度出发,提出了不同的封堵层改善方法。首先,采用两种不同材料的防火板探究了各自的防火、抗热解性能;然后,对比分析无阻火包封堵、阻火包半封堵和阻火包全封堵三种防火封堵方法,并通过试验验证了阻火包防火、隔热的有效性以及仿真方法的正确性;最后,在试验中建立相同的火灾试验条件,构建封堵层结构不同的两种方法模型,从隔热性、烟密性的角度分析了二者的防火优劣性。基于仿真与试验,本文获取了不同因素对高层建筑电缆竖井火灾蔓延的影响规律,提出的防火封堵改善方法可为竖井电缆的布置设计及防火封堵提供有效参考。更多还原

【Abstract】 In recent years,the threat of electrical fires to people’s lives and property has been increasing.However,due to the "chimney effect",once a fire breaks out in a shaft,flames and smoke will spread rapidly in the vertical direction,causing great harm to the cables and even the building.In this paper,we have conducted a study on the spread of fires in cable shafts and the methods of fire protection and blocking.We have constructed a fire model for cable shafts,analysed the effects of fire sources,ventilation,ageing of fire protection materials,process defects and multi-layer blocking on fires,conducted a comparative study on different blocking materials and fire stopping package processes,and verified the effectiveness of the simulation model through tests.The fire protection advantages and disadvantages of different blocking layer structures are finally analysed based on the tests.The main aspects include the following:(1)Firstly,the theoretical basis of cable shaft fires is introduced,a simulation model of cable shaft fires is constructed using FDS,results are analysed for physical quantities such as temperature,smoke concentration and heat radiation intensity,and the development trend of cable shaft fires is explored,which leads to subsequent research work.(2)From the perspective of the fire spread law,a control variable method was used to analyse the effects of the fire source,ventilation,ageing of fire protection materials,process defects and multi-layer blocking,and the physical quantities such as smoke concentration,temperature and HRR(heat release rate)inside the model during the fire were used as characteristic quantities to investigate the spread law of cable shaft fires under different influencing factors.The simulation results show that there are significant differences in the effects of these factors on the spread of fire and the temperature distribution within the shaft.(3)From the perspective of fireproof sealing,different methods of improving the sealing layer are proposed.Firstly,the fireproofing and pyrolysis resistance of two different materials are investigated;then,the three methods of fireproofing are compared and analysed: fireproofing without firestopper,half firestopper and full firestopper,and the effectiveness of fireproofing and thermal insulation of firestopper and the correctness of the simulation method are verified through tests.Finally,in the test,the same fire test conditions were established,and the two methods with different blocking layer structures were constructed,and the advantages and disadvantages of the two methods were analysed in terms of heat insulation and smoke tightness.Based on the simulation and test,this paper obtains the influence law of different factors on the spread of fire in cable shafts of high-rise buildings,and the proposed method of improving fireproof sealing can provide effective reference for the design of cable shaft arrangement and fireproof sealing.更多还原