分布式光纤感温火灾探测系统在公路隧道中应用的若干影响因素研究

发布时间：2018-04-19 10:27

本文选题：分布式光纤 + 火灾探测　；参考：《中国科学技术大学》2014年硕士论文

【摘要】：分布式光纤感温火灾探测系统(Distributed Optical Fiber Temperature Fire Detection System,以下简称DTS)能在隧道火灾发生初期给出报警响应,对灾害应急及时开展、控制火灾规模、减少人员伤亡和财产损失有重大作用,已被广泛应用于公路隧道火灾监测中。然而,DTS在公路隧道火灾中应用的实验研究较少,且对于DTS在公路隧道安装参数(距顶高度、敷设间距)及适用的隧道高度,国内尚未出台专门的国家级规范,各地方标准和国外规范的规定也不尽相同。因此开展DTS在公路隧道中应用的相关影响因素研究,对于实际应用和推广具有重大意义。本文在广泛调研国内外隧道火灾探测技术及DTS应用现状基础上,首先介绍了DTS系统测温原理及结构设计,并对实验使用的DTS系统的温度精度、定位精度和响应时间等基础性指进行测定,表明所采用的DTS系统符合实验要求,可以开展后续真实火灾实验。其次,搭建了30m×7.6m×7.8m全尺寸隧道火灾实验平台,开展真实火灾实验研究,通过对隧道温度分布及DTS报警响应情况进行对比分析,得出如下结论： (1)隧道纵向通风时,DTS报警位置较实际火源位置随风向发生偏移,报警时间随着风速增加变长,实际隧道火灾探测中需考虑通风对DTS探测位置的偏移影响。 (2)火源功率和位置影响了隧道内的温度分布,与DTS响应时间均呈正相关关系,小功率火源火灾初期温度、位于车底和地面的火源引起的火灾都可能达不到一般定温型火灾报警阈值,火灾定温报警失效,需设置差温报警对其响应。 (3)光纤安装距隧道顶部100mm时的温升速度和报警响应时间较距顶300mm时快,通过各地方规范的对比,为更有利于火灾探测,DTS在公路隧道内实际应用时适宜安装位置应为距隧道顶部50-100mm。第三,通过对不同高度(5m、6m、7m、8m、9m、10m、11m、12m)隧道火灾发生发展过程的FDS数值模拟,对比分析发现,随着隧道高度增加,相同距顶安装高度的DTS报警位置偏移量增大,报警响应时间延长,达到12m高度时,定温探测报警失效。最后,采用真实火灾实验和CFD数值模拟相结合的方法,研究结果表明DTS最大敷设间距与隧道高度有直接关系,敷设间距随着隧道高度增加而减小,并给出了不同高度隧道对应的DTS最大敷设间距建议值。
[Abstract]:The distributed Optical Fiber Temperature Fire Detection system (DTSs) can give alarm response in the early stage of tunnel fire, which plays an important role in developing disaster emergency, controlling fire scale, reducing casualties and property loss.It has been widely used in highway tunnel fire monitoring.However, there are few experimental studies on the application of DTS in highway tunnel fire, and there is no national standard for DTS installation parameters (distance from top height, laying distance) and applicable tunnel height in China.Local standards and foreign norms are not the same.Therefore, it is of great significance to study the influencing factors of the application of DTS in highway tunnel.Based on the investigation of tunnel fire detection technology and the application of DTS at home and abroad, this paper first introduces the principle and structure design of DTS system temperature measurement, and the temperature precision of DTS system used in experiment.The measurement of the positioning accuracy and response time shows that the DTS system can meet the requirements of the experiment and can carry out the follow-up real fire experiment.Secondly, the fire experiment platform of 30m 脳 7.6m 脳 7.8m full-scale tunnel is built, and the real fire experimental research is carried out. Through the comparison and analysis of tunnel temperature distribution and DTS alarm response, the conclusions are as follows:1) in longitudinal ventilation of tunnel, the alarm position of DTS is offset with the wind direction, and the alarm time increases with the increase of wind speed. The influence of ventilation on the location of DTS should be considered in the actual tunnel fire detection.(2) the power and position of the fire source affect the temperature distribution in the tunnel, and are positively correlated with the response time of DTS.The fire caused by the fire source located at the bottom of the vehicle and the ground may not reach the general fixed temperature fire alarm threshold, and the fire fixed temperature alarm is invalid, and the differential temperature alarm should be set to respond to the fire alarm.The temperature rise speed and alarm response time of optical fiber installation from the top of the tunnel is faster than that from the top of the tunnel. Through the comparison of the local specifications, the suitable installation position should be 50-100 mm. from the top of the tunnel in order to facilitate the practical application of the 100mm in the highway tunnel.Thirdly, through the FDS numerical simulation of the fire development process of the tunnel fire at different heights (5m / 6m / 7m / 8m / 9m / 10m / 10m / 10m / 11m / 12m), it is found that with the increase of the tunnel height, the offset of the DTS alarm position of the same height from the top of the tunnel increases, and the alarm response time is prolonged.When the height of 12m is reached, the fixed temperature detection and alarm fail.Finally, by combining real fire experiments with CFD numerical simulation, the results show that the maximum laying distance of DTS is directly related to tunnel height, and the laying spacing decreases with the increase of tunnel height.At the same time, the maximum distance between DTS and tunnel with different height is given.
【学位授予单位】：中国科学技术大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U458

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