多风井混合式通风矿井反风演习实践

为探究全矿反风风速对硐室火灾烟气蔓延的影响,利用FDS火灾数值模拟软件构建矿井巷道三维模型,模拟全矿反风风速为1.0、1.5、2.0、2.5 m/s条件下的火灾场景,分析不同反风风速下硐室左右两侧烟气浓度和巷道内能见度的变化情况。研究结果表明：当全矿反风风速为1.0 m/s时,巷道进风侧风流紊乱,烟气出现明显回流现象;随着反风风速的增大,进风侧风流方向开始反转,巷道内能见度和风流反向速率不断增大;反风风速为1.5~2.0 m/s较合适,且当针对硐室火灾事故采取救灾救援措施时,反风风速需确保大于临界风速2.5 m/s。

     

超微细改性Al(OH)3填充LDPE/EVA的研究

Al(OH）3是LDPE／EVA主要的阻燃，消烟填充剂。研究了不同粒度，表面处理及填充量的Al(OH）3对LDPE／EVA的氧指数（OI），烟密度等级（SDR）和物理机械性能的影响。     

Experimental study on the effect of lateral concentrated smoke extraction on smoke stratification in the longitudinal ventilated tunnel

Smoke is the main cause of death in tunnel fires. It is one of the important measures to maintain smoke stratification in the early stage of tunnel fire. This article focused on experimentally studying the combined effect of lateral concentrated smoke extraction and longitudinal ventilation on the smoke stratification, which never be revealed before. The velocity of the smoke layer and air layer, vertical temperature distribution, and the flow patterns of the smoke were measured. It was found that the longitudinal ventilation and lateral concentrated smoke extraction would affect the flow of the smoke and change the shear velocity between the smoke layer and air layer, then, the patterns of the smoke layer will be affected. And the flow patterns with Froude (Fr) number can be classified into three categories: (a)Fr < 0.6 , with stable smoke stratification; (b) 0.6 < Fr < 0.85 , with a stable smoke stratification but the blurring interface; and (c) Fr > 0.85 , the smoke layer is completely unstable. The result can provide a reference for ventilation design of immersed tube tunnels.     

Effect of Bio-Based Cobalt Alginate on the Fire Safety and Mechanical Properties for Epoxy Resin

There is a growing demand to develop epoxy resins (EP) with smoke suppression as well as satisfactory flame retardancy. Herein, bio-based cobalt alginate is successfully fabricated and incorporated into EP to prepare EP/Cobalt Alginate composites with better fire safety performance. The addition of cobalt alginate reduces the thermal-decomposition rate, temperature at maximum weight-loss rate of EP, whereas obviously improves the thermal stabilities at a higher temperature range. Furthermore, the addition of cobalt alginate substantially reduces the fire hazard of EP, resulting in 56.2% reduction in peak heat release rate, as well as 17.8% and 56.3% reduction in total smoke production and peak smoke production rate, respectively, compared with EP matrix. Moreover, the presence of cobalt alginate increases smoke-suppressant properties, according to the smoke density test. Additionally, the incorporation of cobalt alginate has no obviously destructive effect on the mechanical properties of EP, while EP/Cobalt Alginate-3 exhibits a 27.0% improvement in impact strength. In prospective, this study may provide a significant method for producing eco-friendly flame retardant EP.     

氢氧化铝/有机改性蒙脱土复合改性沥青性能研究

采用氢氧化铝(ATH)和两种有机改性蒙脱土(OMMT-C、OMMT-F)对沥青进行阻燃抑烟改性,旨在提高隧道沥青路面的阻燃抑烟性能。通过测试三大指标来评价ATH/OMMT复合改性沥青的常规性能,测试极限氧指数(LOI)与烟密度(SDR)来评价其阻燃抑烟性能,利用动态剪切流变(DSR)试验研究其流变性能。基于综合指数法优选出ATH/OMMT复合改性沥青的最佳复掺配比,通过热重(TG)试验分析了ATH/OMMT复合改性沥青的热解燃烧特性并建立了阻燃性能预测模型。研究结果表明,ATH/OMMT复合阻燃剂提高了沥青的稠度与软化点,降低了沥青的低温性能。当ATH掺量为10%(质量分数),OMMT-C掺量为3%(质量分数)时,复合改性沥青的综合性能最优,其极限氧指数大于23%,符合路用阻燃沥青的标准,同时烟密度相对基质沥青降低了33.9%,初始分解温度较基质沥青提高了3~6 ℃,分解残余量提高率最高可达61.3%。ATH/OMMT-C复合阻燃剂通过阻隔热交换通道提高了沥青的阻燃抑烟性能,通过增加沥青的弹性成分提高了沥青的复数模量与车辙因子,以及高温抗变形能力。     

锥形量热法研究木质素基膨胀型阻燃剂对环氧树脂阻燃抑烟效果

以来自自然界储量第二的木质素作为膨胀型阻燃剂的基体,通过接枝氮、磷元素成功合成碳源、酸源、气源三位一体的木质素基膨胀型阻燃剂(Lig?T),实现了良好的阻燃性能.将Lig?T按照不同含量添加到环氧树脂(EP)中制备EP/Lig?T复合材料,以锥形量热测试考察复合材料的热稳定性能和阻燃性能,并重点考察复合材料在接近真实火...     

弹用红外干扰发烟剂研制

对铜基红外干扰发烟剂的配方及影响配方性能的主要因素进行了实验研究，并对其性能进行了测试。结果表明，该发烟剂不仅对中、远红外光具有优良的干扰能力，而且对可见光、激光也具有良好的遮蔽能力。该发烟剂还具有装填密度大，不导电，耐高、低温性能、相容性和稳定性能良好等特点。     

对烟幕微粒的终端沉降速度研究

传统烟幕理论认为，在烟幕形成后，烟幕微粒受到重力的作用开始沉降，同时受到空气阻力和浮力的作用，最后使烟幕微粒达到终端沉降速度，这个速度方程可以通过Stokes圆球阻力理论求得，并被用来分析烟幕的性能。本文通过外场实验研究和理论分析认为，终端沉降速度公式并不适合分析烟幕性能。     

膨胀石墨烟幕发生装置烟流颗粒运动规律与试验研究

针对膨胀石墨设计了一种简易烟幕发生装置,该装置利用烟火药燃烧时释放出的热量使可膨胀石墨膨化并分散于空中,形成膨胀石墨干扰烟幕。基于该装置建立了烟流颗粒(膨胀石墨颗粒)扩散规律的理论计算模型,对烟幕发生剂反应参数与烟流颗粒运动规律进行计算,得到烟流颗粒的运动方程。同时,对该装置进行了试验研究,并通过高速摄影记录烟流颗粒运动规律,试验结果表明烟流颗粒理论运动规律与试验结果相符,能够描述烟流颗粒的运动规律。     

准石墨化碳气凝胶对香烟烟气吸附研究

碳气凝胶与金属钠在一定温度下共同加热后,其骨架中无序态石墨微晶发生准石墨化.在700℃,所得准石墨化碳气凝胶样品的比表面积为1167 m2·g-1,孔体积为1.16 cm3·g-1,介孔所占比例为90％,有利于提高对烟气组分的吸附能力.无定形碳基质中石墨微晶在准石墨化过程中发生重排,导致气凝胶表面性质和孔结构演变.