Comparison of PIV and PDA droplet velocity measurement techniques on two high-pressure water mist nozzles

• Published in: Fire safety journal Vol. 44; no. 8; pp. 1030 - 1045
• Main Authors: Husted, Bjarne Paulsen, Petersson, Per, Lund, Ivar, Holmstedt, Göran
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.11.2009; Elsevier
• Subjects: Annan samhällsbyggnadsteknik; Applied sciences; Atom and Molecular Physics and Optics; Atom- och molekylfysik och optik; Building technical equipments; Building Technologies; Buildings; Buildings. Public works; Civil Engineering; Detection. Firefighting. Smoke control. Evacuation; Engineering and Technology; Exact sciences and technology; Fire protection; Fysik; High-pressure nozzles; Husbyggnad; Measurements; Measurements. Technique of testing; Medicin och hälsovetenskap; Natural Sciences; Naturvetenskap; Other Civil Engineering; PDA; Physical Sciences; PIV; Samhällsbyggnadsteknik; Spray; Teknik; Water mist; Water mist; High-pressure nozzles; Spray; Measurements; PIV; PDA; Firefighting; Measurement result; Speed measurement; Experimental device; Anemometer; Experimental study; Droplet; High pressure; Nozzle; Measurement technique; System description; Measurement method
• ISSN: 0379-7112
• DOI: 10.1016/j.firesaf.2009.07.003

The need for reliable measurement of droplet velocities and droplet size has increased with the more widespread use of water mist systems. Two optical measuring techniques have been investigated, Particle Image Velocimetry (PIV) and phase Doppler anemometry (PDA). Measurements have been performed on two high-pressure nozzles, a hollow cone nozzle and a full cone nozzle. Both methods performed well close to the nozzle and further away from the nozzle. In the intermediate region the results obtained with PIV are biased against the larger droplets. The two methods complement each other, PIV giving the instantaneous velocity field and PDA giving both the droplet velocity and droplet size at a point. The measurement indicates that higher throw length can be archived with a full cone nozzle compared to the hollow cone nozzle, if both nozzles have the same cone angle and flow rate.