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Metrology for Non-Contact Rainbow Thermometry



Cary Presser


NIST recently acquired a commercially available, state-of-the-art droplet diagnostic system that determines the size, velocity, and temperature of in-flight individual droplets. This non-contact diagnostic will be used to determine droplet characteristics in the NIST rerference spray combustion facility. The temperature-measuring component of this system, manufactured by Aerometrics (a TSI company), was developed in 1993 and integrated into an existing droplet size and velocity laser diagnostic system. Phase Doppler interferometry (PDI) is a nonintrusive, real-time, optical diagnostic technique that gives the size and velocity of individual droplets as they are transported through a measurement volume that is defined by the intersection of two coherent interfering laser beams. Droplet velocity is determined by the temporal frequency of the modulated scattering signal as the droplet moves through the interference pattern. The three strongest Ar-ion laser lines are used to provide the three components of velocity. Droplet size is determined by the scattered light phase difference between two off-axis detectors. PDI has been modified to incorporate non-contact rainbow refractometry (RR), and thus allows droplet temperature to be obtained simultaneously with droplet size and velocity.
Metrology for Non-Contact Rainbow Thermometry


droplet diagnostic system, fire research, non-contact rainbow thermometry, PDI, phase Doppler interferometry, reference spray combustion facility, spray


Presser, C. (2001), Metrology for Non-Contact Rainbow Thermometry, Metrology for Non-Contact Rainbow Thermometry (Accessed April 19, 2024)
Created March 1, 2001, Updated February 17, 2017