Performance of a Monofiber Optical Probe in Determining the Droplet Size and Velocity in Spray Systems Compared with a High-Speed Camera

Optical fiber probe has been recently developed for characterizing the liquid dispersed in gas in droplet form, but its performance has yet been identified for an actual spray system. This work aims to compare the performance of a monofiber optical probe in characterizing the hydrodynamics in spray systems with that of a high-speed camera. Initially, both techniques determined the same series of droplets produced by a syringe. The droplet velocities and sizes obtained from the optical probe were in accordance with the high-speed camera when the droplet coalescence was filtered out from the data. Second, a full-cone spray nozzle was used and the average velocities from the two techniques were close, but the off-center collision on the probe and the difference in size limits caused the discrepancy in the size determination. However, the probe is still beneficial to determine the droplet hydrodynamics and local liquid fraction, the essential characteristics of a spray system.