Print Email Facebook Twitter Towards a calibration-free ultrasonic clamp-on flow meter: Pipe geometry measurements using matrix arrays Title Towards a calibration-free ultrasonic clamp-on flow meter: Pipe geometry measurements using matrix arrays Author Massaad, J. van Neer, P.L.M.J. van Willigen, D.M. Pertijs, M.A.P. de Jong, N. Verweij, M.D. Publication year 2019 Abstract Current ultrasonic clamp-on flow meters are manually calibrated. This process is based on manual placement of two single-element transducers along a pipe wall. Due to the usually unknown pipe properties and inhomogeneities in the pipe geometry, the axial distance of the transducers needs to be manually calibrated to align the location of the emitted beam on the receiver. In this work it is presented an automatic calibration procedure, based on matrix transducer arrays, to provide calibration information that would normally be entered into the instrument manually prior to ultrasonic clamp-on flow measurements. The calibration consists of two steps: First, along the axial direction of the pipe, Lamb waves are excited and recorded. Then, the measured time signals are combined with the Rayleigh-Lamb dispersion equation to extract pipe wall thickness and bulk wave sound speeds. Second, along the circumferential direction of the pipe, a specific Lamb wave mode is excited and recorded, from which the pipe diameter is estimated. The potential of both calibration procedures is shown, and the necessity of a matrix transducer array (i.e. small elements) is highlighted. © 2019 Acoustical Society of America. All rights reserved. Subject CalibrationFlow measurementSurface wavesTransducersUltrasonic wavesAutomatic calibrationCalibration freeCalibration informationCalibration procedureCircumferential directionDispersion equationsPipe wall thicknessSingle element transducersFlowmeters To reference this document use: http://resolver.tudelft.nl/uuid:5590af9f-f4d8-4dfc-a3f0-9ae6f74bbd64 TNO identifier 881859 Publisher Acoustical Society of America ISSN 1939-800X Source Proceedings of Meetings on Acoustics, 178th Meeting of the Acoustical Society of America, ASA 2019, 2 December 2019 through 6 December 2019 Article number 65001 Document type conference paper Files To receive the publication files, please send an e-mail request to TNO Library.