High accuracy optical particle sizing in phase-Doppler anemometry

Optical particle sizing in backscatter.

Several possibilities for the use of elastic light scattering in the backscatter range (scattering angle theta(s) > 140 deg) for determination of size, velocity, and refractive index of spherical particles are investigated. First the phase Doppler technique is considered. Numerical simulations of light scattering with the Lorenz-Mie theory are used to show that the phase Doppler technique is un...

Using Phase Doppler Anemometry and High Speed Imaging to Analyze MDI Spray Plume Dynamics

Superimposed Non Interfering Probes to extend the Phase Doppler Anemometry size range

In classical phase Doppler systems three detectors are commonly used to determine the particles size whatever, basically, this technique requires only two detectors. The third detector is in fact mainly used to overcome the 2 ambiguity on phase-shift measurements. In the present work an alternative solution is introduced which allows to keep the same accuracy and dynamic range of the size measu...

Frequency domain phase - resolved optical Doppler and Doppler variance tomography

Frequency domain phase-resolved optical Doppler tomography (ODT) was developed with Doppler variance imaging capability. It is shown that utilizing the frequency domain method, phase-resolved ODT can achieve much higher imaging speed and velocity dynamic range than the time domain method. Structural, Doppler and Doppler variance images of fluid flow through glass channels were quantified and bl...

On-line detection/estimation scheme in laser Doppler anemometry

Laser anemometers have become a promising technique for estimating velocities in a flow. In this paper, we study their use for onboard aircraft speed of flight estimation. More specifically, this paper addresses the problem of simultaneous detection of the arrival of aerosol particles in a laser anemometer and estimation of their velocity. A joint detection-estimation scheme is proposed. A Like...