Simultaneous measurements of planar profiles of OH radicals and temperature in the field of pressurized methane-air combustion by the PLIF

In recent years, planar laser induced fluorescence (PLIF) has been paid much attention as a method to analyze combustion reactions. PLIF has a capability of non-intrusive and high by sensitive measurement to detect a low number density of chemical species in combustion fields. PLIF has, however, that the signal emission from chemical species is weakened such a disadvantage due to quenching under high pressure combustion conditions. The purpose of this work is to search and optimize spectroscopical conditions that enable to measure planar profiles of chemical species and temperatures simultaneously under high pressures utilizing PLIF. Simultaneous measurement of planar profiles of OH radicals and rotational temperature were successfully made in a combustor pressurized at 1.2 MPa. It was found from these experiments that, (1) the attenuation of OH radical fluorescence under high pressures was reducible when a P₁ line was employed rather than a Q₂ line, (2) the temperature profiles was obtainable simultaneously with those of OH radicals and (3) the temperature profiles in the pressurized combustor were nearly uniform at the cross section under the employed experimental conditions.