Assessment of single-shot temperature measurements by thermally-assisted OH PLIF using excitation in the A2Σ+-X2Π(1-0) band

The present paper reports on the assessment of single-shot 2D temperature measurements by thermally assisted OH PLIF for the excitation of the A(2)Sigma(+)-X-2 Pi (1-0) band. The temperature sensitivity of the ratio between the emission intensity of the (2-0) band and (0-0), (1-1) bands is numerically tested by using a LASKIN software package for the transitions Q(2)(7), Q(1)(8), R-1(14), and P-1(2). It is found to be the most efficient for Q(1)(8), for which the ratio almost linearly depends on the temperature in the range of 1200-2200 K. Fluorescence quenching by oxygen has a minor effect on the results. The capability of the temperature measurements by the thermally assisted OH PLIF has been experimentally tested for a laminar premixed methane/air flame based on comparison with the results of two-line and line-scanning PLIF thermometry. The method is also applied for a partially premixed turbulent swirling flame in a model gas-turbine combustor. The method allows to detect hot regions in turbulent flames. (c) 2020 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

Automated summary

The present study assesses the effectiveness of single-shot 2D temperature measurements using thermally assisted OH PLIF, finding that the method is most sensitive to temperature changes for the Q(1)(8) transitions. Experimental results show that this approach can effectively detect hot regions in turbulent flames.