High-frequency temperature measurements were carefully conducted for a 15 kW buoyant turbulent ethylene diffusion flame over a 15.2 cm diameter gas burner with air co-flow. A dual-thermocouple probe, consisting of two fine-wire thermocouples with 25 μm and 50 μm wire diameters, was used to determine a compensated turbulent gas temperature. A sensitivity analysis shows that temperatures resolved using this dual-thermocouple technique are less sensitive to changes in thermocouple bead size, therefore, uncertainty is greatly reduced even when soot deposition on the thermocouple bead occurs in sooty flames. Mean and root-mean square (rms) fluctuations of gas temperature were recorded in a two-dimensional plane across the flame centerline. The mean gas temperature monotonically decreases away from the flame centerline at most flame heights, except for 1 diameter above the burner, where a temperature dip is observed. The rms temperature peaks shift from the edge of the flame to the center as the height increases. This is due to the enhanced mixing between fuel and air, which is further shown using probability density functions of the local gas temperature. A systematic temperature dataset with high spatial resolution is established for sooty flames, which is valuable for future soot and radiation model validation.

Fire spread is known to accelerate uphill over inclined surfaces due to an intrinsic coupling between geometry and fire-induced flows, especially when the slope exceeds a critical angle. The fundamental relationships which govern this close coupling, however, are not yet fully understood. To investigate these relationships, propane-fueled fires were produced over a tilt table at the Missoula Fire Sciences Lab. Large-scale fire tests with heat-release rates ranging from 81 kW to 2.25 MW were conducted. The angle of inclination, θ, was varied between 0∘ and 30∘. A micro-thermocouple array along the centerline of the table was used to measure downstream gas temperatures. Flames were seen to start attaching to the inclined surface at θ = 18∘, independent of the fireline intensity. The centerline temperatures under attached flame conditions are consistent with McCaffrey's buoyant flame temperature correlation, suggesting the buoyancy-driven nature of the inclined fires. The local gas velocity was measured using temperature-correlation velocimetry through the streamwise temperature signals. Results show that the local flow was accelerated in the attached flame region driven by buoyancy before reaching a peak. Velocity of the flow slowed down after the peak due to weaker buoyancy within the intermittent and plume regions. The mean surface velocity of the attached flame scales directly with the angle of inclination (sinθ) and the fireline intensity (I2/3), providing a promising method to evaluate convective heat transfer using the geometry of the inclined fire.