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The Effect of Measurement Volume Size on Phase Doppler Anemometer Measurements of Glass Mocrospheres



John M. Davis, P J. Disimile


Phase Doppler Anemometry (PDA) is a widely used measurement technique capable of non-intrusively measuring a droplet diameter and up to three components of its velocity, simultaneously. PDA systems are frequently used to characterize spray nozzles and suppressant transport phenomena, which may be further used in model validation. It has been shown that the optical configuration can have a considerable effect on PDA diameter measurements. The current paper is part of an ongoing effort toward the development of a procedure to properly configure a PDA system for the best drop size measurement accuracy and reports on backscatter diameter measurements of glass microspheres using four separate measurement volume sizes. The presented data covers approximate particle to measurement volume diameter ratios from 1/25 to 1/3 which will be useful in providing guidance for the minimum ratio required to acquire backscatter diameter measurements free of errors due to measurement volume effects.
Special Publication (NIST SP) - 984-4
Report Number


Davis, J. and Disimile, P. (2005), The Effect of Measurement Volume Size on Phase Doppler Anemometer Measurements of Glass Mocrospheres, Special Publication (NIST SP), National Institute of Standards and Technology, Gaithersburg, MD, [online], (Accessed May 28, 2024)


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Created January 1, 2005, Updated February 19, 2017