Rapid tuning cw laser technique for measurements of gas velocity, temperature, pressure, density, and mass flux using NO

Abstract

An intracavity-doubled rapid-tuning cw ring dye laser was used to acquire fully resolved absorption profiles of NO line pairs in the A ← X band at 225 nm at a rate of 4 kHz. These profiles were utilized for simultaneous measurements of flow parameters in the high speed 1-D flows generated in a shock tube. Velocity was determined from the Doppler shift measured using a pair of profiles simultaneously acquired at different angles with respect to the flow direction. Temperature was determined from the intensity ratio of the adjacent lines. Pressure and density were found both from the collisional broadening and the fractional absorption. From this information the mass flux was determined. The results compare well to 1-D shock calculations.