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Experimental Methodology for Estimation of Local Heat Fluxes and Burning Rates in Steady Laminar Boundary Layer Diffusion Flames
Published on: June 1, 2016
Experimental study of fuel sootiness effects on flashover
Kuang-Chung Tsai1, Hung-Hsiang Chen
1Dept. of Safety, Health and Environmental Engineering, National Kaohsiung First University of Science and Technology, 2 Juoyue Road, Nantzu, Kaohsiung 811, Taiwan. tsaikc@ccms.nkfust.edu.tw
Journal of Hazardous Materials
|February 4, 2010
Summary
Fuel sootiness significantly impacts fire dynamics, but flashover is primarily determined by reaching a critical heat release rate (HRR). This study confirms that the relationship between HRR at flashover and time to flashover is independent of fuel type.
Area of Science:
- Fire Science
- Combustion Research
- Thermal Hazards
Background:
- Flashover in fires leads to severe injuries and fatalities.
- Radiative heat transfer, influenced by fuel sootiness, is a key mechanism in fire spread.
- Existing empirical correlations for flashover prediction often overlook fuel sootiness.
Purpose of the Study:
- To investigate the influence of fuel sootiness on fire flashover dynamics.
- To determine the relationship between heat release rate (HRR) at flashover and time to flashover (t(fo)) across different fuels.
- To analyze the role of radiative heat transfer and fuel properties in flashover events.
Main Methods:
- Conducted experimental burns using gasoline, n-hexane, iso-propanol, and methanol in circular pans (100-320 mm diameter).
- Fires were contained within pans sized at 1/3 of the ISO 9705 test chamber.
- Measured heat release rate (HRR), chamber temperature, floor heat flux, and time to flashover (t(fo)).
Main Results:
- Heat release rate at flashover and time to flashover were strongly correlated.
- This correlation was found to be independent of the fuel's sootiness or type.
- Increased fuel sootiness enhanced burning due to higher heat feedback but did not alter the flashover criterion.
Conclusions:
- Flashover is critically dependent on achieving a specific heat release rate (HRR) threshold.
- Fuel sootiness influences the burning process and heat feedback but not the fundamental condition for flashover.
- The established HRR criterion for flashover remains consistent across various fuel types and their associated sootiness levels.
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