Laser Velocimeter Seed Particle Sizing by the Whisker Particle Collector and Laser Aerosol Spectrometer Methods

Two different aersol particle sizing systems, the whisker particle collector WPC and the laser aerosol spectrometer LAS, were evaluated for sizing aerosol particles in the size range 0.1 to 3.0 mm. The evaluation tests were conducted using an aerosol of alumina Al203 particles, an aerosol commonly used to provide light-scattering particles for laser velocimeter measurements in high-temperature flows. The measurement accuracy of the LAS was certified by comparison of its measurements to known particle sizes in test aerosols of precisely sized polystyrene latex spheres. The LAS and WPC measurements were then compared for samples taken from the alumina particle aerosols. Some difficulty was encountered in directly comparing these measurements because of the differences in the operating principles of the LAS laser light scattering and the WPC particle captureelectron microscope analysis and the consequent differences in the way the two systems account for prime particles and aggregates or agglomerates of prime particles. Other operational aspects of the two systems are also compared in this report including on-lineoff-line data presentation capabilities, field portability, and measurement limitations at the small particle end of the size range of interest. Keywords Laser velocimeter Particle sizing Laser aerosol spectrometer Aerosol spectrometer Whisker particle collector.