Modeling the effect of roughness on ultrasonic scattering in 2D and 3D

Cegla, Frederic; Jarvis, A. J. C.

doi:10.1063/1.4864874

Cited by 7 publications

(4 citation statements)

References 2 publications

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“…This proves that in this particular study, the mean error does not truly represent the influence of the roughness, but the standard deviation provides information on the average effect of roughness on the flow velocity measurement. This presentation is also consistent with that used by other authors to investigate the effect of scattering from rough surfaces [24].…”

Section: Pipe Roughness Uncertainty Simulationsupporting

confidence: 92%

The Effect of Internal Pipe Wall Roughness on the Accuracy of Clamp-On Ultrasonic Flowmeters

Cegla

2019

IEEE Trans. Instrum. Meas.

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Clamp-on transit-time ultrasonic flowmeters (UFMs) suffer from poor accuracy compared with spoolpiece UFMs due to uncertainties that result from the in-field installation process. One of the important sources of uncertainties is internal pipe wall roughness which affects the flow profile and also causes significant scattering of ultrasound. This paper purely focuses on the parametric study to quantify the uncertainties (related to internal pipe wall roughness) induced by scattering of ultrasound and it shows that these effects are large even without taking into account the associated flow disturbances. The flowmeter signals for a reference clamp-on flowmeter setup were simulated using 2-D finite element analysis including simplifying assumptions (to simulate the effect of flow) that were deemed appropriate. The validity of the simulations was indirectly verified by carrying out experiments with different separation distances between ultrasonic probes. The error predicted by the simulations and the experimentally observed errors were in good agreement. Then, this simulation method was applied on pipe walls with rough internal surfaces. For ultrasonic waves at 1 MHz, it was found that compared with smooth pipes, pipes with only a moderately rough internal surface (with 0.2-mm rms and 5-mm correlation length) can exhibit systematic errors of 2% in the flow velocity measurement. This demonstrates that pipe internal surface roughness is a very important factor that limits the accuracy of clamp on UFMs. Index Terms-Clamp-on flowmeter, roughness, transit time, ultrasound, uncertainties. I. INTRODUCTION T RANSIT-time ultrasonic flowmeters (UFMs) are widely used in many industrial sectors, such as oil and gas, power, nuclear, process, water distribution, and chemical plants. These flowmeters measure flow velocity by calculating the difference in arrival time between the ultrasonic signals that are traveling with the flow (downstream signal) and against the flow (upstream signal). There are two common ways to install the ultrasonic transducers, "inline" and "clampon" (Fig. 1). The installation of the inline UFM requires cutting the pipe and subsequent insertion of a premanufactured and calibrated spool piece that contains integrated ultrasonic transducers. The clamp-on flowmeter only requires transducers to be mounted on the outside of the pipe wall to take a measurement. This clamp-on flowmeter has a number of Manuscript

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Section: Pipe Roughness Uncertainty Simulationsupporting

confidence: 92%

The Effect of Internal Pipe Wall Roughness on the Accuracy of Clamp-On Ultrasonic Flowmeters

Cegla

2019

IEEE Trans. Instrum. Meas.

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“…The distributed point source method (DPSM) [20] was chosen as it is particularly fast and has been shown to simulate realistic ultrasonic signals reflecting of rough surfaces [10,11]. For the particular transducer geometry and wave mode (shear horizontal SH wave) that was simulated it was also shown that the statistics of 2D simulations can be related to those of the full 3D case [21]. In this paper 2D simulations are carried out, but they are not adjusted to match the expected statistics of 3D simulations.…”

Section: Simulation Of the Reflection Of Ultrasonic Signals From Roug...mentioning

confidence: 99%

The effect of corrosion induced surface morphology changes on ultrasonically monitored corrosion rates

Gajdacsi

Cegla

2016

Smart Mater. Struct.

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Corrosion rates obtained by very frequent (daily) measurements with permanently installed ultrasonic sensors have been shown to be highly inaccurate when changes in surface morphology lead to ultrasonic signal distortion. In this paper the accuracy of ultrasonically estimated corrosion rates (mean wall thickness loss) by means of standard signal processing methods (peak to peak-P2P, first arrival-FA, cross correlation-XC) was investigated and a novel thickness extraction algorithm (adaptive cross-correlation-AXC) is presented. All of the algorithms were tested on simulated ultrasonic data that was obtained by modelling the surface geometry evolution coupled with a fast ultrasonic signal simulator based on the distributed point source method. The performance of each algorithm could then be determined by comparing the actual known mean thickness losses of the simulated surfaces to the values that each algorithm returned. The results showed that AXC is the best of the investigated processing algorithms. For spatially random thickness loss 90% of AXC estimated thickness trends were within −10 to +25% of the actual mean loss rate (e.g. 0.75-1.1 mm year −1 would be measured for a 1 mm year −1 actual mean loss rate). The other algorithms (P2P, FA, XC) exhibited error distributions that were 5-10 times larger. All algorithms performed worse in scenarios where wall loss was not distributed randomly in space (spatially correlated thickness loss occured) and where the overall rms of the surface was either growing or declining. However, on these surfaces AXC also outperformed the other algorithms and showed almost an order of magnitude improvement compared to them.

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“…200 sequences of evolving rough surfaces with different realizations of the same RMS evolution were simulated. "A ultrasonic signal simulator": Based on the geometries that were generated by the surface evolution generator, ultrasonic signals for each surface were simulated using the DPSM technique [8]. Only 2D profiles were simulated because this resulted in ~100 faster simulation times.…”

Section: Performance Study Of Axc On Components With Evolving Surfacementioning

confidence: 99%

Mitigating the effects of surface morphology changes during ultrasonic wall thickness monitoring

Cegla¹,

Gajdacsi²

2016

AIP Conference Proceedings

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Modeling the effect of roughness on ultrasonic scattering in 2D and 3D

Cited by 7 publications

References 2 publications

The Effect of Internal Pipe Wall Roughness on the Accuracy of Clamp-On Ultrasonic Flowmeters

The Effect of Internal Pipe Wall Roughness on the Accuracy of Clamp-On Ultrasonic Flowmeters

The effect of corrosion induced surface morphology changes on ultrasonically monitored corrosion rates

Mitigating the effects of surface morphology changes during ultrasonic wall thickness monitoring

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