Abstract
We quantitatively estimated the location and area fraction of a model blockage inside a pipe utilizing guided waves propagating in a liquid inside a pipe. The guided wave was excited and detected by film-type PZT elements wounded around an external pipe surface. Location of the blockage can be estimated from an arrival time of the wave reflected by the blockage and measured propagation velocity. The blocking ratio can be also estimated by comparing the measured amplitude to the predicted one when the profile of the blockage was roughly evaluated prior to the measurement. We also discussed the effect of the flow rate on the amplitude of the reflected wave.
