In the context of the investigations of multiphase flows, e.g. in cooperation with the local brewery, the convective transport phenomena during the fermentation are investigated. Due to the strong turbidity of the medium, the measurement of velocity profiles is complicated. The difficulties of an investigation with a biological fermentation fluid are the many complex interactions between the different three phases (solid, gas, fluid). Furthermore, natural convection processes are superimposed by rising gas bubbles and the high turbidity of the fluid only allow an acoustic velocity measurement. In previous investigation, ultrasonic transducers are used for the non-contact determination of velocity fields in fluids. The results of these past projects show that the measurement signals of the ultrasonic transducers used can be influenced by many factors. In order to verify the results of the transducers and to investigate the existing uncertainties, a flow configuration with a relatively stable reproducible flow pattern is required. In this study, a calibration system for ultrasonic transducers is developed, manufactured and validated by means of optical measurement technology such as the LDA. Finally, a measurement using Ultrasonic Doppler Velocimetry in a model fluid will be compared with an optical measurement technique.
6 lis 2023
30 cze 2022
Klembt , Daniel Meironke , Heiko