LOW INTENSITY (< 155 DB) ACOUSTIC AGGLOMERATION-BENCH -SCALE EXPERIMENTS.

摘要

An experimental study is made of the influence of relatively low intensity acoustics (< 155 dB) on the agglomeration rates of aerosols. Three bench-scale experiments are performed using different aerosols, frequency ranges and sound generators. The aerosol agglomeration experiments are conducted in cylindrical chambers of different dimensions, within which the aerosol is treated in an acoustic field generated by a traveling wave.; The first experiment is the study of dioctylphtalate aerosol coagulation in an acoustic field with frequencies in the 1 kHz to 3 kHz range generated by an electromagnetic sound driver. The second experiment involves the sonic agglomeration study of the sodium pool-fire aerosol using the stem-jet whistle as the sound source generating a frequency from 3 kHz to 18 kHz. The third experiment is related to the ammonium chloride aerosol agglomeration in an acoustic field created by a dynamic siren. Also developed is a computational scheme to study the dynamic behavior of the aerosol system.; Results of the various experiments indicate the validity of the orthokinetic model within experimental errors, the errors reaching as high as 10 per cent for intensity levels of 150 dB and at low acoustic frequencies, with greater error at the higher applied frequencies. Results also indicate the validity of the acoustic removal mechanisms at low intensity levels with deviations of 5 to 10 per cent between theory and experiment at the higher intensity. It is also observed that the agglomeration process is independent of the physical dimensions of the systems under the restrictive condition of wavelength to chamber diameter ratio smaller than unity.; Work on the calibration and data interpretation of the Stober centrifuge and the Delron six stage cascade impactor is presented and utilized to determine the aerodynamic properties and size distribution of the sodium pool-fire aerosol.