Proposal of quantitative measurement of OH radical using planar laser induced fluorescence calibrated by cavity ring-down spectroscopy in turbulent premixed flames

摘要

Planar laser induced fluorescence (PLIF) has been a very important species analysis approach in combustion research, but is most often presented qualitatively. Therefore, another supplementary techniques are needed for quantitative PLIF measurement. In this paper, we propose a quantitative OH concentration measurement method using PLIF calibrated by cavity ring-down spectroscopy (CRDS). The CRDS measurement is firstly applied to a methane-air atmospheric pressure flame on a McKenna burner and determine the OH absolute density. Then the PLIF signal is calibrated by the determined OH concentration on the same flame under the same condition. The calibrated PLIF setup is fixed, and another PLIF setup is added to form a two-line OH-PLIF thermometry to measure the 2D temperature distribution. Finally, a quantitative OH-PLIF measurement method is provided for the turbulent premixed flame on a Bunsen burner based on this setup.