Experimental and theoretical analysis of spill fire dynamics in confined spaces: Heat release rate estimation based on gas concentration variations

IF 7.5 1区工程技术 Q2 ENERGY & FUELS

Fuel Pub Date : 2025-06-21 DOI:10.1016/j.fuel.2025.136009

Jinlong Zhao , Xu Zhai , Changyang Zhang , Weiguang Kong , Hanchao Ma

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引用次数: 0

Abstract

Spill fires in confined spaces, such as those in underground substations and ship engine rooms, pose significant threats to fuel safe utilization. In this study, a 3 m × 3 m × 4 m experimental platform was developed to investigate n-heptane spill fires under fuel discharge rates ranging from 5.8 to 12.6 g/s. By characterizing spread process and gas concentration evolution (O₂, CO₂, CO), a novel method for estimating the heat release rate (HRR) was proposed. The combustion process was categorized into four distinct stages: burning layer spread stage, transition stage, ghosting fire stage, and extinction stage. A parameter τ was proposed to represent the relationship between fuel discharge rate and confined space volume, and the extinction time t_e was found to be positively correlated with τ. Oxygen concentration followed a three-phase decline pattern (slow-rapid-slow decline), with extinction thresholds stabilizing at 15.0 % O₂, 3.8 % CO₂, and 1200 ppm CO, regardless of the discharge rate. Furthermore, an HRR calculation model tailored for confined space spill fires was established and validated for accuracy. The research results can be used for fire risk assessment in confined space to ensure the fuel safe utilization.

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密闭空间溢火动力学的实验与理论分析：基于气体浓度变化的热释放率估算

地下变电站和船舶机舱等密闭空间的泄漏火灾对燃料的安全利用构成重大威胁。在本研究中，建立了一个3 m × 3 m × 4 m的实验平台，研究了5.8 ~ 12.6 g/s燃料排放速率下的正庚烷泄漏火灾。通过表征扩散过程和气体浓度演变（O2, CO2， CO），提出了一种估算放热速率（HRR）的新方法。燃烧过程可分为四个阶段：燃烧层扩散阶段、过渡阶段、隐火阶段和熄灭阶段。提出了表征燃料排放率与密闭空间体积关系的参数τ，消光时间te与τ呈正相关。氧气浓度呈三相下降模式（慢-快-慢下降），无论放电速率如何，消失阈值稳定在15.0% O2, 3.8% CO2和1200 ppm CO。此外，建立了针对密闭空间溢出火灾的HRR计算模型，并对其准确性进行了验证。研究结果可用于密闭空间火灾风险评估，保证燃料的安全利用。

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

Fuel 工程技术-工程：化工

CiteScore

12.80

自引率

20.30%

发文量

3506

审稿时长

64 days

期刊介绍： The exploration of energy sources remains a critical matter of study. For the past nine decades, fuel has consistently held the forefront in primary research efforts within the field of energy science. This area of investigation encompasses a wide range of subjects, with a particular emphasis on emerging concerns like environmental factors and pollution.