Prediction of toxic species in fire

大多数火灾死亡与闪络后高温火灾产生的有毒产品的远程运输有关，特别是与一氧化碳有关[S1、S2]。目前，数值工具在描述这些有毒产品的运输方面是有效的，但不能准确地预测火灾中产生的量--因此缺少来源[S2，S3]。为了扩大消防安全工程(FSE)方法的范围，并为从业者提供更有效的工具，迫切需要健壮的、经过充分验证的方法，从整体上解决问题，从而完善整个链条并提供真正的预测能力[S3]。这将为许多新的应用打开大门，包括火灾取证，以帮助确定死亡原因，补充昂贵的全面火灾测试，并最终在建筑设计方面，并可能改变FSE方法的应用和开发。至关重要的是，任何这种方法都能得到消防界的有效利用，因此它在计算上必须不苛刻(这样它才能在顾问通常使用的计算机上运行)，并且必须有效适应现实世界火灾的具体要求，即涉及非常广泛的长度尺度的大型建筑物情景，以及往往是复杂的燃料来源，在这些情况下，对有毒产品产量的重大贡献可能来自气相复杂的形成过程，也可能来自固相，通过可燃边界材料的热解[S2]。这里提出了一种先进的方法，其中每个过程都可以有效地适应，基于每个感兴趣的化学物种的输运方程的解。这项建议的重点是CO预测，但该方法未来可能会扩展到包括其他有毒物种。需要解决的关键研究问题是如何最有效地实现化学源项的关闭，这是湍流燃烧系统中建模的关键挑战。将研究不同的方法，包括一种基于使用简化的准层流表达式直接求解耦合物质平衡方程的基本方法，以及一种更复杂的方法，它是火焰面模拟方法的扩展。这些预测将以现有的方法为基准，这些方法依赖于有毒产品产量的传统火焰面表示和文献[S4]中描述的简单涡流分解概念方法的扩展。新方法将根据实际火灾场景的相关实验数据进行验证，这些实验数据旨在充分测试新建模策略的一般性[S2、S3、S5]。考虑到对计算资源和精确度的根本竞争要求，将就该方法的利用提出详细的建议。巴普拉斯卡斯，V.，莱文，B.C.，Gann，R.G.，Paabo，M.，Harris，Jr，R.H.，Peacock，R.D.&Yusa，S.(1991)火灾危险分析的毒力测量，特殊酒吧。827，NIST，1991年12月2.皮茨，W.M.(1995)封闭火灾中一氧化碳的全球当量比概念和形成机制，Prog。能源燃烧。科学，第21卷，第197-237S3页。普瑟，D.和普瑟，J.(2003年)在消防安全工程中包括火化学和毒性的可能性，BRE客户报告202804,2003年3月26日。海德，S.M.和莫斯，J.B.(2003)在被污染的室内火灾中模拟一氧化碳的生产，过程。第7次集成交响乐。《消防安全科学》，第395-406页，第5页。史密斯，D.A.，马歇尔，N，Shaw，K.和Colwell，S.(2001)将大规模火灾性能与单一燃烧物品测试相关联。第9个接口Interflam会议，第531-542页

Most fire deaths are associated with the remote transport of toxic products produced in hot post-flashover fires, and with carbon monoxide (CO) in particular [S1, S2]. Currently, numerical tools are effective at describing the transport of these toxic products, but incapable of accurately predicting the quantities generated in a fire - thus the source is missing [S2, S3]. In order to extend the scope of fire safety engineering (FSE) methods, and provide more effective tools for practitioners, there is an urgent need for robust and well-validated methodologies which address the problem in its entirety, thus completing the chain and provided a true predictive capability [S3]. This would open the door to a host of new applications, including fire forensics to assist in determining causes of fatalities, supplementing expensive full-scale fires tests, and ultimately in building design, and could transform the application and exploitation of FSE methodologies. It is essential that any such methodology can be effectively exploited by the fire community, so it must be undemanding computationally (so that it can be run on computers typically used by consultants) and must effectively accommodate the specific requirements of real-world fires, i.e. large-scale building scenarios involving a very broad range of lengthscales, and multiple and often complex fuel sources, where significant contributions to toxic products yields may arise both from complex formation processes in the gas phase and directly from the solid-phase, via pyrolysis of combustible boundary materials [S2]. Here an advanced methodology is proposed in which each of these processes can be effectively accommodated, based on the solution of transport equations for each chemical species of interest. The focus of this proposal is on CO prediction, but the method could in future be extended to include other toxic species. The key research question to be addressed is how to most effectively achieve chemical source term closure which is the essential modelling challenge in turbulent combustion systems. Different approaches will be investigated, including a fundamental method based on directly solving the coupled species balance equations using simplified quasi-laminar expressions, and a more sophisticated method which is an extension of the flamelet modelling approach. These predictions will be benchmarked against existing approaches which rely on conventional flamelet representations of toxic product yields and extensions to the simple eddy breakup concept approach, as described in the literature [S4]. The new methods will be validated against relevant experimental data from realistic fire scenarios designed to fully test the generality of the new modelling strategies [S2, S3, S5]. Detailed recommendations will be prepared on exploitation of the methodology, considering the fundamentally competing demands of computational resources and accuracy.References========S1. Babrauskas, V., Levin, B. C., Gann, R. G., Paabo, M., Harris, Jr, R. H., Peacock, R. D. & Yusa, S. (1991) Toxic potency measurement for fire hazard analysis , Special Pub. 827, NIST, Dec 1991S2. Pitts, W.M. (1995) The Global Equivalence Ratio concept and the formation mechanisms of carbon monoxide in enclosure fires , Prog. Energy Combust. Sci., vol. 21, pp. 197-237S3. Purser, D. & Purser, J. (2003) The potential for including fire chemistry and toxicity in fire safety engineering , BRE Client report 202804, 26 Mar 2003S4. Hyde, S.M. & Moss, J.B. (2003) Modeling CO production in vitiated compartment fires , Proc. 7th Int. Symp. Fire Safety Science, pp. 395-406 S5. Smith, D.A., Marshall, N., Shaw, K., & Colwell, S. (2001) Correlating large-scale fire performance with the Single Burning Item test , Proc. 9th Int. Interflam Conf., pp. 531-542