摘要
针对石化企业火灾处置需求,开展了多组液氮泡沫长距离输送实验,分析了液氮泡沫在静置和输送状态的析液与再发泡过程,提出了液氮泡沫在消防管线内再发泡物理模型(P-S模型),指出消防管线内的逸散气体、液滴、相邻气泡间瞬态压力差、气泡间空间等是液氮泡沫再生成的必要条件,揭示了消防管线内液氮泡沫析液-发泡-再析液-再发泡的循环机制,提出了液氮泡沫输送动力强度概念。实验结果证明液氮泡沫在消防管线内能输送1000 m距离,液氮泡沫在DN80的消防水带内输送400 m时出现“长管阻力效应”,输送更远距离需要的输送动力强度将增加2~3倍;输送液氮泡沫的动力强度是输送泡沫混合液液体的1.5~1.9倍;对相同的液氮泡沫输送流量,在消防管线流通面积增加1倍后,输送动力强度降低69%。为向火灾现场远距离输送大流量液氮泡沫,应采用大管径消防管线高压输送。
Aiming at the fire disposal requirements of petrochemical enterprises,several sets of long-dis-tance transport experiments of liquid nitrogen foam were carried out,the liquid nitrogen foam evolution and re-foaming process in static and transport state were analyzed,and the physical model of re-foaming of liquid nitrogen foam in fire fighting pipeline(P-S model)was proposed.It was pointed out that the es-caping gas,droplets,the transient pressure differ-ence between adjacent bubbles,and the space be-tween bubbles in the fire fighting pipeline were the necessary conditions for the regeneration of liquid ni-trogen foam.The“elutriation-foaming-reelutriation-refoaming”circulation mechanism of liquid nitrogen foam in the fire fighting pipeline was revealed,and the concept of conveying power strength of liquid ni-trogen foam was proposed.The experimental results showed that the liquid nitrogen foam can transport 1000 m in the fire pipeline,and the“long pipe re-sistance effect”occurred when the liquid nitrogen foam was transported 400 m in the fire hose of DN80,and the conveying power strength required for longer distance would be increased by 2~3 times.The pow-er strength of conveying liquid nitrogen foam was 1.5~1.9 times that of conveying foam mixture liq-uid.For the same transmission flow of liquid nitrogen foam,when the flow area of the fire pipeline was doubled,the conveying power strength was reduced by 69%.In order to provide long-distance transporta-tion of liquid nitrogen foam with large flow rate to the fire site,high pressure transportation should be a-dopted by large diameter fire fighting pipelines.
作者
郎需庆
牟小冬
张广文
尚祖政
Lang Xuqing;Mou Xiaodong;Zhang Guangwen;Shang Zuzheng(State Key Laboratory of Chemical Safety,Shandong,Qingdao,266104;SINOPEC Research Institute of Safety Engineering Co.,Ltd.,Shandong,Qingdao,266104)
出处
《安全、健康和环境》
2023年第8期10-16,共7页
Safety Health & Environment
基金
应急管理部消防救援局科技项目(2021XFCX17),低沸点易燃液体储罐火灾高效处置技术及装备
中国石化科技部项目(3200006),大流量液氮泡沫灭火系统在石化场所应用技术与装备研究。
关键词
液氮泡沫
长距离输送
输送动力强度
物理模型
泡沫灭火
liquid nitrogen foam
long distance transport
conveying power strength
physical model
foam extinguishing
