Initial Evaluation of Focused Ultrasound for In-Situ Measurements of Small Particles in Flowing Water Streams

Abstract

The potential capability of a focused ultrasound technique for in-process measurement of suspended particles in water systems was studied by challenging the focused ultrasound instrumentation with various sizes and concentrations of spheres in a single pass test system. Correlation between particle counts per unit time as measured by focused ultrasound and particles per unit volume as measured by a HIAC particle counter was determined for 1–5-, 10-, and 20-µm spheres. Correlation coefficients were 0.97 and 0.90 for the 10-µm and 20-µm spheres, respectively. The ultrasound transducer used does not appear to be sensitive enough to detect the 1–5-µm spheres. The uncertainty involved in expressing particle counts as measured by focused ultrasound on a volume basis is discussed.