Accession Number : ADP008979

Title :   Size-Discriminated Velocity Cross-Correlation Measured by a Single Channel Phase Doppler Velocimeter,

Corporate Author : IMPERIAL COLL OF SCIENCE TECHNOLOGY AND MEDICINE LONDON (UNITED KINGDOM) DEPT OF MECHANICAL ENGINEERING

Personal Author(s) : Hardalupas, Y. ; Liu, C. H.

Report Date : 23 JUL 1992

Pagination or Media Count : 7

Abstract : It would be nice to investigate droplet dispersion in sprays by measuring two velocity components and their time averaged cross-correlation as a function of droplet size with a single channel phase Doppler system by adapting Hoagland's method, commonly used in laser Doppler and hot wire velocimeter. This involves taking three non-orthogonal measurements of size and velocity, from which two velocity components and their cross correlation coefficient can be determined for each droplet size. This method requires simpler optics and electronics than a two channel phase Doppler system and removes uncertainties in the coincidence of the two colour probe volumes. The application of Hoagland's method to a phase Doppler velocimeter was examined theoretically by calculating the sizing response curves and the visibility of the Doppler signals using the geomerical optics sprays. The Gaussian intensity distribution of the incident laser beams did not introduce additional sizing uncertainties relative to the direct measurement with a two channel phase Doppler instrument, but the uncertainty of the velocity and flux measurements with the suggested method is larger than for a two channel system. (Author)

Descriptors :   *FUEL SPRAYS, LASER VELOCIMETERS, DOPPLER EFFECT, HOT WIRE ANEMOMETERS, CROSS CORRELATION, MULTICHANNEL, PHASE MODULATION, GREAT BRITAIN.

Subject Categories : Fuels
      Optical Detection and Detectors

Distribution Statement : APPROVED FOR PUBLIC RELEASE