A MINIATURIZED SEMICONDUCTOR FIBER OPTIC PHASE-DOPPLER ANEMOMETER (DFPDA) WITH APPLICATIONS TO LIQUID SPRAYS

For many particle size measurements in industrial applications conventional phase-Doppler systems are unsuitable due to their large size. For such purposes a PDA probe has been developed which consists of miniaturized transmitting and receiving optics and fibre optic coupling to the laser source and photodetector. A laser diode and avalanche photo diode have been used to reduce size and power consumption and this makes the PDA probe very mobile and flexible. The receiving optics is designed for easy alignment and is therefore suitable for field measurements and measurements in hostile environments. Design and performance specifications of the PDA probe are given in detail in this paper and example measurements, including comparisons with conventional PDA systems, are presented.