Droplet sizes from deluge nozzles

• The droplet size distributions from one high velocity nozzle (HVK44) and one medium velocitynozzle (MVK41) have been investigated by two different measurement techniques. Those arePhase Doppler Anemometry (PDA) and a photographic technique developed by Oxford Lasers.The project was initiated because earlier measurements using the PDA technique resulted insuspiciously small droplets. The present work indicates that this was partly because of the nonoptimumoptics that were chosen at that time. In this project the best optics available were chosen,resulting in measuring larger droplets than in the previous work. However, the PDA-method stillseem to give too small droplets due to a too small measurable droplet size region. The imagingtechnique is capable to measure larger droplets than the PDA-technique (using the optics appliedin this project), and hence it gives larger VMDs (Volume Median Diameters) in sprays wherelarger droplets than 1200μm are present. In the spray from the HVK44 nozzle, the largest dropletmeasured with the imaging technique was about 3700μm. The same technique gave VMDs from600 to 1300μm, while the PDA-technique gave VMDs from 550 to 750μm at different locationsin the spray pattern. In the spray from the MVK41-nozzle, the largest droplet measured with theimaging technique was about 1600μm. The same technique gave VMDs from about 200 –800μm with most of the VMDs between 300 and 600μm. The PDA-technique gave VMDs fromabout 400 to 770μm at different locations in the MVK41 spray pattern. When the large dropletswere not present, the VMDs from the two different techniques were more similar.

Publikations- och innehållstyp

vet (ämneskategori)

rap (ämneskategori)