Commercial time-of-flight (TOF) ultrasonic flowmeters (UFM) are rapidly expanding in the general industry. Among the different techniques that can be applied to determine the TOF of ultrasonic waves, the cross-correlation method presents numerous advantages, such as robustness for weak signals and noise suppression. However, the selection of an appropriate reference wave is presumably a key element in the precise measurement of TOF. In this paper, an algorithm to compute an accurate TOF is proposed. The form of the electric signal received by the transducer is obtained from an acoustically forced underdamped oscillator model, and the analytical solution of the model is proposed as a reference wave. In order to validate the effectiveness of this procedure, a UFM system is designed and tested in a flowmeter calibration test rig. It is demonstrated that the use of the presented scheme overcomes the average method limitations, and turns out to be a convenient solution in a wide range of conditions. Robust measurements of near-zero flow values are acquired, which allow the achievement of a high dynamic range. The error curve of the proposed system have been obtained, revealing that the absolute value of the relative errors is lower than 2% within all the spectrum of flow rates considered (from 0.2 to 150 $\text{m}^{3}$ /h). Results demonstrate that the algorithm provides high-precision measurements within a wide dynamic range. The algorithm is portable and versatile: it can be adapted to different types of transducers without the need of additional measurements, allowing adjusting parameters on-the-fly for an optimal performance of the ultrasonic flowmeter (UFM) system.

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High-Precision Time-of-Flight Determination Algorithm for Ultrasonic Flow Measurement

Uncertainty of mass flow measurement using centric and eccentric orifice for Reynolds number in the range 10,000 ≤ Re ≤ 20,000

An asymmetric orifice can be added to a surge tank of a hydro power plant to dampen the mass oscillation. This allows a reduction of the required volume and a more stable behavior of the overall hy...

https://www.tandfonline.com/doi/pdf/10.1080/19942060.2018.1443837

Design criteria for a type of asymmetric orifice in a surge tank using CFD

Effects of Exit Fan Angle on the Heat Transfer Performance of Sweeping Jet Impingement

Application of artificial neural networks instead of the orifice plate discharge coefficient

Reynolds number dependence of an orifice plate

https://cyberleninka.org/article/n/1036641.pdf

Calibration of an ultrasonic flow meter for hot water

The flow instruments used in thermal power plants cannot be calibrated directly for the actual process conditions, since no traceable calibration facility with known uncertainty is available. A systematic investigation of the relevant influence parameters is therefore needed. It was found in earlier investigations that the dominant influences on the measurement uncertainty are the flow velocity profile and the temperature. In the present work, we report on our experimental study of the temperature and Reynolds number dependence of a new ten-path ultrasonic flow meter prototype. An improved measuring program is developed that allows for a systematic characterization. Special emphasis was placed on producing and validating well defined velocity profiles on a precision calibration flow rig. It was also for the first time intended and validated to generate fully developed Reynolds-similar velocity profiles for different temperatures so that the two main influence parameters, namely temperature and Reynolds number, can be clearly characterized separately. Since such ideal measurement conditions are not found in practical applications, the approach is also tested for a disturbed flow condition. A well defined disturbance is generated with a new flow disturber.

https://iopscience.iop.org/article/10.1088/0957-0233/25/7/075304/pdf

Investigation of a ten-path ultrasonic flow meter for accurate feedwater measurements

Zusammenfassung Stereoscopic Particle Image Velocimetry (SPIV) eignet sich als schnelles und präzises Messverfahren zur zeitlich und räumlich hochaufgelösten Ermittlung von 3D-Geschwindigkeitsverteilungen in Rohrleitungen. Die Methode wird mit dem bekannten Laser Doppler Velocimetry (LDV)-Messverfahren und Computational Fluid Dynamics (CFD)-Simulationen am Beispiel einer stark gestörten Strömung hinter einem Drallgenerator bewertet. Erstmalig können so SPIV-Messabweichungen bei der Volumenstrombestimmung von deutlicher kleiner als 2% an einem komplexen Strömungszustand nachgewiesen werden. Abstract Stereoscopic Particle Image Velocimetry (SPIV) is a fast and precise measurement method for the investigation of 3D velocity distributions in pipes with high temporal and spatial resolutions. The method is tested in a strongly disturbed flow by comparison with Laser Doppler Velocimetry (LDV) measurements and Computational Fluid Dynamics (CFD) simulations. For the first time measurement deviations less than 2% for the flow rate determination could be proven under such complex conditions.

Messabweichung der Stereo-PIV im Vergleich zu LDV und CFD anhand einer definiert gestörten Rohrströmung

Ventilation systems include a variety of components for which necessary pressure loss data is often unavailable. Computational fluid dynamics simulations could substitute for expensive measurements, but validation simulations with suitable data are crucial to assess model uncertainties. Existing CFD validation studies either did not focus specifically on pressure losses, only covered few components, or did not include recent developments in turbulence modelling. In the present work, 33 bends, 4 gates and 2 tees were simulated using a consistent approach. Computational fluid dynamics simulations were validated with published data: rectangular high-edge and wide-edge bends from the experimental dataset of Sprenger, gates and diverging tees from the SMACMA guide. The considered flows cover important basic flow phenomena: deflection, splitting and flow separation. The 39 components were simulated with three turbulence models at 14 Reynolds numbers. The simulations predicted pressure loss coefficients accurately for various components. Cases with strong flow separation regions were most challenging. The model prediction uncertainty was assessed by carrying out simulations with three selected turbulence models. As in the experimental data from Sprenger, the simulations showed a distinct dependence of pressure loss coefficients on the Reynolds number for bends. In contrast, for abrupt deflections and flow separation at sharp edges, the Reynolds number dependency was minor. 
 Practical Application
 Technical pressure loss data of ductwork components is needed for the dimensioning, optimisation, and energy assessment of ventilation systems. The present validation study assesses the present state of the art of CFD simulations to determine pressure loss coefficients and the resulting prediction uncertainties.

Karsten Tawackolian

Papers

Reynolds number dependence of an orifice plate

Calibration of an ultrasonic flow meter for hot water

Investigation of a ten-path ultrasonic flow meter for accurate feedwater measurements

Messabweichung der Stereo-PIV im Vergleich zu LDV und CFD anhand einer definiert gestörten Rohrströmung

Validation of computational fluid dynamics simulations for determining pressure loss coefficients of ventilation components