The diagnostic techniques for simultaneous velocity and relative OH distribution, simultaneous temperature and relative OH distribution, and three component velocity mapping are described. The data extracted from the measurements include statistical moments for inflow fluid dynamics, temperature, conditional velocities, and scalar flux. The work is a first step in the development of a detailed large eddy simulation (LES) validation database for a turbulent, premixed flame. The low-swirl burner used in this investigation has many of the necessary attributes for LES model validation, including a simplified interior geometry; it operates well into the thin reaction zone for turbulent premixed flames, and flame stabilization is based entirely on the flow field and not on hardware or pilot flames.

Hydrocarbon autoignition has long been an area of intense fundamental chemical interest, and is a key technological process for emerging clean and efficient combustion strategies. Carbon-centered radicals containing an –OOH group, commonly denoted ˙QOOH radicals, are produced by isomerization of the alkylperoxy radicals that are formed in the first stages of oxidation. These ˙QOOH radicals are among the most critical species for modeling autoignition, as their reactions with O₂ are responsible for chain branching below 1000 K. Despite their importance, no ˙QOOH radicals have ever been observed by any means, and only computational and indirect experimental evidence has been available on their reactivity. Here, we directly produce a ˙QOOH radical, 2-hydroperoxy-2-methylprop-1-yl, and experimentally determine rate coefficients for its unimolecular decomposition and its association reaction with O₂. The results are supported by high-level theoretical kinetics calculations. Our experimental strategy opens up a new avenue to study the chemistry of ˙QOOH radicals in isolation.