环境风条件下非连续桦木阵列水平火蔓延特性研究

Characteristics of Horizontal Flame Spread over Discrete Birch Rod Arrays Under the Influence of Ambient Wind

摘要

采用实验研究与理论分析相结合的方法，通过改变环境风速与燃料床宽度研究了强迫对流条件下环境风速、阵列列数和阵列间距对多列离散桦木阵列水平火蔓延过程中的火焰长度、火蔓延速度和质量损失速率等特征参数变化规律的影响。结果表明，离散燃料阵列火蔓延速度与环境风速之间存在良好的线性关系；与阵列列数相比，阵列间距对质量损失速率影响不大；结合传热分析，建立了质量损失速率与环境风速之间的幂律关系。火焰长度随阵列列数的增大呈现幂律增长的趋势，无量纲火焰长度与无量纲热释放速率之间有较好的幂律关系。另外，本文还确定了环境风作用下单列离散桦木阵列顺流火蔓延的临界蔓延间距，并依据斯坦顿数与达姆科勒数之间的无量纲关系给出了临界火蔓延判定准则。

Abstract

In order to investigate the characteristics of horizontal flame spread over discrete birch rod arrays under the influence of ambient wind，the effects of ambient wind speed，array column number and array spacing on the horizontal flame spread of discrete birch rod array under forced convection condition were analyzed by varying the ambient wind speed and fuel bed width in this paper.The results show that there is a good linear relationship be-tween the flame spread rate of discrete fuel array and the ambient wind speed.Compared with the array column number，the array spacing has less effect on the mass loss rate.The power-law relationship between the mass loss rate and the ambient wind speed was established.The flame length shows a power-law growth trend with the in-crease of array column number，and there is a good exponential relationship between the dimensionless flame length and the dimensionless heat release rate.In addition，the critical spacing of flame spread of single-row discrete fuel array under the influence of ambient wind was determined，and the critical criterion for discrete flame spread was established based on the exponential relationship between Stanton number and Damkohler number.

关键词

离散桦木阵列 / 水平火蔓延 / 环境风 / 燃料床宽度 / 临界蔓延准则

Key words

discrete birch rod array / horizontal flame spread / ambient wind / fuel bed width / critical criterion

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基金资助

国家自然科学基金资助项目(51804338)

湖南省自然科学基金资助项目(2023JJ60169)

湖南省教育厅科学研究项目优秀青年项目(24B0968)

湖南安全技术职业学院校级科研课题(AY25B001)