Moisture estimation by measurement of attenuation of the acoustic resonance mode

This article describes the experimental setup for estimating the moisture in wood pellets and wood chips by measuring the attenuation of the first longitudinal acoustic resonance mode that is excited in the cylindrical container. The resonance quality is related to losses of sound energy, which are brought about by several phenomena and moisture is one of them. The metrological traceability was carried out by the "loss on drying" method, supported by calibrated balance and a set of reference materials. Using the "loss on drying" method, the amount of moisture in wood pellets was measured in the ranges of 0 %mc to 10 %mc. For acoustic tests in the range of 0 % mc to 56 % mc, reference woodchip material was used. Experimental results show feasibility of concept of traceable acoustic moisture measurement based device.