Numerical analysis of thermal mechanism in downward flame spread over inverted surfaces of discrete inclined solid fuels

Luo, Shengfeng1,2; Zhao, Yanli3; Zhou, Bo2

2024-12-01

10.1016/j.ijthermalsci.2024.109311

INTERNATIONAL JOURNAL OF THERMAL SCIENCES   影响因子和分区

1290-0729

1778-4166

This investigation is propelled by engineering challenges associated with heat transfer during fire incidents on inclined surfaces, such as those observed in pitched roof fires, which hold significant implications for fire safety engineering and energy conservation. Drawing inspiration from real-world fire dynamics, this study delves into the downward flame spread over inverted solid fuel surfaces across a range of inclination angles, bridging the gap between theory and practice. Detailed analysis of temperature distribution, flame characteristics, and gas-phase reactions reveals critical insights into the complex interplay governing heat behavior under these conditions. The observed reduction in flame thickness and standoff distance with increasing inclination underscores the influence of buoyancy-induced plumes. This work developed a dimensionless formula that accounts for both buoyancyinduced plumes and diffusion rates perpendicular to the fuel, successfully capturing the variation in flame thickness with inclination angles. Furthermore, our findings show that the average flame spread rate escalates with higher inclination angles, attributed to enhanced gas-phase reactions near the flame front that lead to intensified heat transfer and a subsequent increase in temperature within the solid phase. The study also uncovers a competitive mechanism between flame "jumps" and heat transfer to the unburned zone, causing an initial increase and then a decrease in flame spread rates with increasing discrete gap size at larger inclination angles. Conversely, at smaller inclination angles, flame progression halts as the discrete gap size increases, due to inadequate heat transfer to the adjacent discrete fuel, resulting in the cessation of flame spread. This study not only advances our understanding of the thermal processes underpinning flame spread in inclined configurations but also offers crucial insights for developing more effective fire protection strategies and thermal protection systems in engineering applications.

Flame spread Thermal analysis Discrete fuel Inverted and inclined surface Flame jump

SCI

英语

通讯

National Natural Science Foundation of China["52306144","52206150"] ; Shenzhen Science and Technology Program[KCXFZ20230731093902005] ; Postdoctoral Later-stage Foundation Project of SUSTech["K22327502","2021-JCJQ-JJ-0418"] ; Guangdong Basic and Applied Basic Research Foundation[2024A1515010889]

Thermodynamics ; Engineering

Thermodynamics ; Engineering, Mechanical

WOS:001294357100001

ELSEVIER FRANCE-EDITIONS SCIENTIFIQUES MEDICALES ELSEVIER

ENGINEERING

Web of Science

1.Shenzhen Technol Univ, Sino German Coll Intelligent Mfg, Shenzhen 518118, Peoples R China
2.Southern Univ Sci & Technol, Dept Mech & Aerosp Engn, Shenzhen 518055, Peoples R China
3.Shanghai Inst Technol, Coll Urban Construct & Safety Engn, Shanghai 200000, Peoples R China

Luo, Shengfeng,Zhao, Yanli,Zhou, Bo. Numerical analysis of thermal mechanism in downward flame spread over inverted surfaces of discrete inclined solid fuels[J]. INTERNATIONAL JOURNAL OF THERMAL SCIENCES,2024,206.

Luo, Shengfeng,Zhao, Yanli,&Zhou, Bo.(2024).Numerical analysis of thermal mechanism in downward flame spread over inverted surfaces of discrete inclined solid fuels.INTERNATIONAL JOURNAL OF THERMAL SCIENCES,206.

Luo, Shengfeng,et al."Numerical analysis of thermal mechanism in downward flame spread over inverted surfaces of discrete inclined solid fuels".INTERNATIONAL JOURNAL OF THERMAL SCIENCES 206(2024).