Utilizing spectroscopy to quantify Thermal transport In fLame sprEad

Uncontrolled fire in the built and wild environment remains a major societal issue; climate change and an increasing elderly population suggest a worsening of fire damage within the following years. The flame spread rate (Vf) is the principal quantity to assess the danger of a fire. Accurately predicting thermal transport to the unburnt material is critical to predicting the Vf.

Improved quantification of the modes by which flames spread can aid in the prevention and control of nonstationary fires.

Combined simultaneous multi-dimensional temperature distributions of the gas with the condensed-phase are required to calculate heat flux to the surface.

UTILE is tailored to understand flame spread (FS) by measuring heat flux with multi-dimensional ultrafast laser diagnostics. A canonical FS configuration (flat plate) with well-known boundary conditions and optical access will be built.

Fs/ps Hybrid Rotational Coherent Anti-Stokes Raman Spectroscopy (HRCARS) will be employed for the gas-phase measurements. Phosphor thermometry will be used to measure the surface temperature.

No fire studies have used simultaneous multi-dimensional temperature measurements of the gas and condensed-phase to calculate heat flux. PIV will measure the airflow boundary layer, and CH or OH chemiluminescence will locate the reacting flame front.

UTILE is not limited to quantifying heat flux but is a platform to advance the state-of-the-art in ultrafast laser diagnostics.

Pushing limitations in 2D HRCARS and ultra-broadband HCARS will decrease experimental time and increase species sensitivity to the opposed and concurrent FS studies.

Using multi-photon excitation for phosphor thermometry has the potential to improve multi-dimensional surface thermometry.

Combining a modern experimental setup with tailored laser diagnostics will provide novel data quantifying heat flux leading to FS. Improving Vf models will benefit fire safety and refine the predictability of CFDs.