Investigation of the combustion law of delayed ignition ethanol spill fire in longitudinal ventilation

IF 4.9 2区工程技术 Q1 ENGINEERING, MECHANICAL

International Journal of Thermal Sciences Pub Date : 2024-11-29 DOI:10.1016/j.ijthermalsci.2024.109575

Xue jing Hu, Cheng hao Ye, Jia xing Li, Mei qing Xia, Pei hong Zhang

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Abstract

The environmental conditions under which sustained spill fire accidents occur are complex and variable, and this paper investigates experimentally the effect of longitudinal ventilation in tunnel on the combustion law of delayed ignition spill fires. Experiments on instantaneous ignition and spill fires with delay of 10 s, 20 s, and 30 s were carried out using ethanol at a spill rate of 78 ml/min under a longitudinal wind speed of 0–1.5 m/s in tunnel. The results show that with the increase of longitudinal wind speed the flame inclination of the spill fire increases and the flame length first increases and then decreases. By analysing the force on the fuel layer and the force on the flame, and combining with the previous research, the prediction models of flame length and flame inclination were established. In the case of longitudinal wind speed, the spill fire burning area increases and then decreases with the increase of wind speed, and there is a critical wind speed, which is related to the delayed ignition time. The heat loss of the substrate in the longitudinal wind and the influence of the flame morphology on the thermal radiation feedback of the flame were considered, and it was found that the heat transfer of the fuel layer with the increase of the wind speed was gradually transitioned from the radiation dominated to the convection dominated. It was found that there was a general trend of increasing combustion rate with increasing wind speed and delayed ignition time.

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纵向通风条件下延迟点火乙醇溢出火灾燃烧规律的研究

持续溢油火灾发生的环境条件复杂多变，本文通过实验研究了隧道纵向通风对延迟点火溢油火灾燃烧规律的影响。在0 ~ 1.5 m/s的纵向风速条件下，以78 ml/min的乙醇为燃料，在隧道内进行了延迟10 s、20 s和30 s的瞬时点火和溢出火灾实验。结果表明：随着纵向风速的增大，溢火火焰倾斜度增大，火焰长度先增大后减小；通过对燃料层受力和火焰受力的分析，结合前人的研究，建立了火焰长度和火焰倾角的预测模型。纵向风速下，随着风速的增加，溢火燃烧面积先增大后减小，且存在一个临界风速，该临界风速与延迟点火时间有关。考虑了基材在纵风中的热损失以及火焰形态对火焰热辐射反馈的影响，发现燃料层的换热随风速的增加逐渐从辐射为主过渡到对流为主。结果表明，随着风速的增大和点火时间的延长，燃烧速率有增大的趋势。

本文章由计算机程序翻译，如有差异，请以英文原文为准。

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来源期刊

International Journal of Thermal Sciences 工程技术-工程：机械

CiteScore

8.10

自引率

11.10%

发文量

531

审稿时长

55 days

期刊介绍： The International Journal of Thermal Sciences is a journal devoted to the publication of fundamental studies on the physics of transfer processes in general, with an emphasis on thermal aspects and also applied research on various processes, energy systems and the environment. Articles are published in English and French, and are subject to peer review. The fundamental subjects considered within the scope of the journal are: * Heat and relevant mass transfer at all scales (nano, micro and macro) and in all types of material (heterogeneous, composites, biological,...) and fluid flow * Forced, natural or mixed convection in reactive or non-reactive media * Single or multi–phase fluid flow with or without phase change * Near–and far–field radiative heat transfer * Combined modes of heat transfer in complex systems (for example, plasmas, biological, geological,...) * Multiscale modelling The applied research topics include: * Heat exchangers, heat pipes, cooling processes * Transport phenomena taking place in industrial processes (chemical, food and agricultural, metallurgical, space and aeronautical, automobile industries) * Nano–and micro–technology for energy, space, biosystems and devices * Heat transport analysis in advanced systems * Impact of energy–related processes on environment, and emerging energy systems The study of thermophysical properties of materials and fluids, thermal measurement techniques, inverse methods, and the developments of experimental methods are within the scope of the International Journal of Thermal Sciences which also covers the modelling, and numerical methods applied to thermal transfer.