Seeding Materials

The choice of the right seeding material to scatter the light from laser beams or a light sheet can be crucial to the acquisition of successful experimental data.

Numerous properties of the particle material have to be taken into consideration when selecting the appropriate seeding medium for a particular measurement task. Mean particle size is only one of the parameters. Others include specific gravity, particle shape, width of size distribution, surface characteristics and refractive index.

To satisfy seeding requirements for different flow applications, a range of seeding materials and equipment are available from Dantec Dynamics.

Polyamide seeding particles (PSP)

These are produced by polymerisation processes and therefore have a round but not exactly spherical shape. They are microporous and strongly recommended for water flow applications.

Hollow glass spheres and silver-coated hollow glass spheres (HGS & S-HGS)

Intended primarily for liquid flow applications, these are borosilicate glass particles with a spherical shape and a smooth surface. A thin silver coating further increases reflectivity.

Fluorescent polymer particles (FPP)

These particles are based on poly (methyl methacrylate). Fluorescent dye (Rhodamine B:) is homogeneously distributed over the entire particle volume. In applications with a high background light level, fluorescent seeding particles can significantly improve the quality of vector maps from PIV and LDA measurements.

The receiving optics must be equipped with a filter centred on the emission wavelength (excitation max.: 550 nm; emission max.: 590 nm).