A practical two-transducer ultrasonic flow meter
Abstract: Nowadays ultrasonic transducers are extensively used. Many industrial systemscarry out their measurement process by taking the advantage of ultrasoundwaves. Sound of frequencies above audible range is called ultrasound, ultrasonic waves are classified under category of mechanical waves. Likewise all other mechanical waves, ultrasound needs material environment called medium to propagate through by moving the particles. Since the end of seventies, ultrasonic flow meters have been widely designed and applied in different industrial plans mainly related to fluid mechanics, chemistry, oil industry, etc. However, the initial motive of this thesis was to design a reliable mass flow meter applicable in controling the precise amount of energy transferred through gas pipe lines.The mass flow meter presented in this thesis is based on a two-transducerultrasonic measurement set up where both transducers emit ultrasonic beamsimultaneously. In this thesis we describe how by checking the amplitudes and timings of the received echoes many valuable physical properties of the flowing liquid can be revealed. In other words, we are able to calculate the speed of sound in the liquid, the flow velocity as well as the liquid's acoustic impedance and its density by only investigating the amplitudes and timings of the received ultrasonic echoes. Moreover, we show that frequency behaviour of the system and the liquid can be illuminated thoroughly.As a master thesis, this project partially stands on previous works in thisfield and mainly on the works done by Dr. Jan van Deventer and Dr. JonnyJohansson and various scientific publications. In coming discussions not onlydo we systematically take advantage of previous thoughts, designs and resultsin order to explore further achievements, but also we present many new solu-tions. This thesis aims towards introducing new electronic solutions and signal processing techniques to reduce the uncertainty of the estimations and to speed up the computation.
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