The acoustical resonance measurement techniques in this project provide a nonintrusive and realtime measurement of mass loading and sizing of particles fluidized by a gas phase. The speed of sound in a two-phase mixture of particles in gas decreases as the mass density of the particles increases. By measuring the decrease in the resonant frequencies, which are linearly related to the speed of sound, the mass density of the particles is determined. Because the speed of sound is dispersive with the frequency dependence of the sound speed provides a method of determining the particle sizing by measurement of the frequencies of different resonant modes. For realistic applications, a longitudinal resonance is required for the acoustical resonance measurement. A first order acoustical analysis of this nonintrusive technique applied to longitudinal resonances is used for the conditions found in the pneumatic conveyance of pulverized coal in electrical utility power plants. The analytical investigation includes evaluation over the full operating ranges of the plant. Experimental measurements on a closed loop tests laboratory scale test stand and at a power plant are conducted to verify the technique. The analyses are used to interpret the results of the experimental measurements.
