SBIR-STTR Award

A particle sizing technique that operates in conjunction with laser velocimetry is proposed. The technique uses a non-intrusive single particle counter based on a pulse height analyzer. It is expected that a size range of 0.1 um to 10 um will be attainable. Lower size limits would require ensemble measurements which cannot be readily used with laser velocimetry, since the size of each particle is necessary. The technique has been successfully used to measure spray droplets between 5 and 300 um. It is expected that with proper development the dynamic size range will be extended to 0.1 um, including irregularly shaped particles as found in laser velocimetry.

A technique to measure the size of particles in addition to their velocity in laser doppler velocimetry is proposed. The studies conducted during phase I show the feasibility of this technique under laboratory controlled experiment. In phase II a working prototype will be produced and demonstrated at aedc's facilities. The technique uses laser beams of unequal diameters to remove the gaussian ambiguity normally present in ldv. Studies conducted during phase I with polystyrene particles of 1.1 micrometers to 3.3 micrometers in diameter showed very good agreement between the experiments and the numerical predictions. These studies also point out that to measure the flows expected at aedc's facilities, a more powerful laser and a faster particle sizing electronic processor are needed. These elements will be part of the advanced prototype developed during phase II.