http://orcid.org/0000-0001-5498-6467
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ABSTRACT
Thin-layered n-heptane pool fires are burned with varied pool depths under longitudinal ventilation velocities ranging between 0.5–2.5 m/s in a reduced scale tunnel model. The combined effects of ventilation, pool size, and depth are investigated on the heat release rate, temperature distribution, and mass loss rate of fire. The gas temperature distribution and heat release rate results indicate that the critical ventilation velocity is achieved around 1 m/s in the scaled model, corresponding to 3.6 m/s in the real scale tunnel. It is observed that the gas temperature downstream of the fire increases at 2.5 m/s ventilation due to an enhancing effect of oxygen supply to the fire and increased flame deflection towards the leeward side of the pan. Results show that maximum heat release rate and total heat release normalized by fuel amount tend to occur at critical ventilation velocity. The measured mass loss rates show a considerable increasing trend with pool depth.
Funding
This work was supported by Middle East Technical University Scientific Research Projects Funding (BAP-03-02-2013-003). Sina Shafee acknowledges scholarship support from the Scientific and Technological Research Council of Turkey (TUBITAK 2215, Ph.D. Scholarship Program for Foreign Citizens).
Nomenclature
| A | = | cross-sectional area of the tunnel (m2) |
| E | = | energy release (MJ) |
| G | = | gravitational acceleration (m/s2) |
| H | = | tunnel height (m) |
| HGV | = | heavy good vehicle |
| HRR | = | head release rate |
| L | = | length scale (m) |
| = | mass loss rate (g/s) | |
| M | = | molar weight (g/mol) |
| MLR | = | mass loss rate |
| NTHR | = | normalized total heat released |
| = | heat release rate (kW) | |
| T | = | temperature (°C, K) |
| TC | = | thermocouple at combustion zone |
| TCTree | = | thermocouple tree |
| TD | = | thermocouple at downstream |
| TU | = | thermocouple at upstream |
| U | = | velocity (m/s) |
| = | volumetric flow rate (m3/s) | |
| X | = | molar fraction |
Subscripts
| A | = | air |
| C | = | convective |
| cr | = | critical |
| f | = | flow |
| F | = | full scale |
| M | = | model |
Superscript
| A | = | analyzer |
Greek symbols
| = | density | |
| = | oxygen depletion factor |