The Measurement of the Transient Temperature of Gas by Laser Interferometry

Abstract

In order to measure the transient temperature of gas, a laser interferometry was applied. When the density of gas changes, the effective optical path length of the test beam changes with a corresponding change of the refractive index. The change in temperature of the gas therefore can be determined by measuring the pressure and the shift of the interference fringes with a pair of phototransistors. In this study, examples of the temperature change measurement of the gas owing to only the expansion, to the compression and expansion with a piston motion, and to the compression with flame propagation were described. It is recognized that interferometry is a useful method for the measurement of the transient temperature of the gas in the field of combustion research.