Observations of an Acoustic Aerosol Particle Transducer

Shape Determination of Aerosol Particles Using an Acoustic Transducer

“…Secondly, the frequencies of the detected signal were found to be consistent with the fundamental frequency ( f ) and harmonics with odd multiples of f , i.e., 3f , 5f , 2 , as expected for an organ pipe with one open end. These observations were also documented for acoustic transducers of several con"gurations and dimensions [1,3]. Third, acoustic signal traces and power spectra were similar for all particles investigated.…”

“…The reader is referred to references [2, 4}7] for the development and applications of the acoustic transducer dated from the 1960s. Although not reported in reference [1], graphite "bers with 7)3 mm diameter and aspect ratios exceeding 200 were also drawn through the acoustic transducer [3]. The above observations for PSL spheres were in general true for these graphite "bers.…”

“…The sections of the acoustic transducer, in the order of the #ow direction (from left to right in Figure 1), are the inlet tube, the contraction, the capillary tube, and the expansion, followed by the outlet tube. For experimental details, the reader is referred to reference [1]. The key reported "ndings are as follows.…”

“…The experimental e!ort described below was an attempt to establish such a capability. It is worthwhile noting that the "rst subharmonic peak at 3 f of the power spectra due to spherical aerosol particles appeared to be the most energetic among all peaks including the fundamental frequency [1,3]. A preliminary study showed that with graphite "bers, the peak in power spectra is the highest at the fundamental frequency f .…”

“…A recent study revealed how an acoustic transducer detected spherical particles [1]. The particles tested were polystyrene latex (PSL) spheres.…”