2020 年 62 巻 202 号 p. 325-332
Temperature is one of the important parameters for understanding the combustion phenomena, and various laser diagnostics for quantitative measurement of temperature have been developed. However, there are physical factors which cause difficulties of laser diagnostics at high pressure conditions. Laser Induced Thermal Grating Spectroscopy (LITGS) is expected as a potential non-intrusive laser diagnostics for high pressure combustion because it is considered that the LITGS signal increases with an increase in pressure. LITGS can derive quantitative temperature at the crossing point of two incident pump lasers. Rapid excitation and subsequent quenching create a thermal grating, and the density perturbation is measured as the LITGS signal. Temperature can be evaluated from the oscillation frequency of the LITGS signal. In this paper, the fundamental theory of LITGS, applications for temperature measurement, and recent studies of LITGS are explained. In the final part of this paper, an example of LITGS application to oxygen enriched methane/oxygen/nitrogen premixed flame at high pressures is introduced.
