Analysis and testing of a new method for drop size and velocity measurements using laser light scatter interferometry
Abstract
Drop size and velocity can be measured simultaneously using an optical system which is the same as a laser Doppler velocimeter except that three detectors are located at selected spacings behind the receiver aperture. Drops passing through the intersection of the two beams scatter light which produces an interferrence fringe pattern. The temporal frequency of the fringe pattern is the Doppler difference frequency which is linearly proportional to the drop velocity while the spatial frequency is linearly related to the drop diameter. The spacing of the fringes is also dependent upon the light wavelength, beam intersection angle, drop refractive index (unless reflected light is measured), and the location of the receiver. The theoretical analysis was verified, signal phase processing methods were evaluated, and the effects of signal quality upon the measurements were investigated.
- Publication:
-
Combustion Fundamentals Research
- Pub Date:
- April 1984
- Bibcode:
- 1984cfr..nasa...31B
- Keywords:
-
- Drop Size;
- Fuel Sprays;
- Laser Beams;
- Laser Interferometry;
- Light Scattering;
- Size Determination;
- Velocity Measurement;
- Diffraction Patterns;
- Phase Shift;
- Reflection;
- Signal Processing;
- Spatial Resolution;
- Two Phase Flow;
- Lasers and Masers