To provide a gas temperature measuring method capable of stably measuring a high gas temperature over a long period.
The infrared absorption rate in a prescribed wave range in an infrared absorption region is calculated by FT-IR (Fourier transform infrared spectrometer) 10 wherein an incidence part 11 is arranged oppositely to a heating element and light emitted from the heating element enters the incidence part through a measuring gas, and the gas temperature is calculated by a temperature operation means 20 based on the infrared absorption rate calculated by the FT-IR. For example, the infrared absorption quantity A1 on some wavelength λ1 is proportional to EXP (-E1/kT), and the infrared absorption quantity A2 on another wavelength λ2 is proportional to EXP (-E2/kT) [E1, E2 are theoretical radiant energies of the wavelengths λ1, λ2, respectively, k is the Boltzmann's constant, and T is the gas temperature]. The temperature T can be determined from the expression -α(E1-E2)/(k*Log(A1/A2)) [α is a constant] from the relation, and A1/A2 can be determined from the infrared absorption rate calculated by the FT-IR.
INOUE KEITA
MUTA KENJI
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