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Beat Birkhofer, Alban Debacker, Simone Russo, Stefano Ricci, Didier Lootens
In-line rheometry based on ultrasonic velocity profiles: comparison of data processing methods

Appl. Rheol. 22:4 (2012) 44701 (9 pages)

Ultrasonic Velocity Profiling with Pressure Drop (UVP+PD) is a technique, which allows the measurement of the shear rate dependent viscosity non-invasively in a laminar pipe flow. To assess the performance of different data processing approaches for the extraction of the rheometric values, model fluids are characterized under well defined flow conditions created with a piston setup. Considering the shear rate range available in the pipe flow, a good quantitative agreement is found between the in-line measurements and the off-line measurements made with a rotational rheometer

Cite this publication as follows:
Birkhofer B, Debacker A, Russo S, Ricci S, Lootens D: In-line rheometry based on ultrasonic velocity profiles: comparison of data processing methods, Appl. Rheol. 22 (2012) 44701.

Johan Wiklund, Beat Birkhofer, SAK Jeelani, Mats Stading, Erich J. Windhab
In-line rheometry of particulate suspensions by pulsed ultrasound velocimetry combined with pressure difference method

Appl. Rheol. 22:4 (2012) 42232 (10 pages)

The in-line rheometer concept based on the combination of the ultrasonic velocity profiling (UVP) technique and pressure difference (PD) measurements was utilized for investigating the influence of particle concentration and size distribution on the rheology of particulate suspensions in pipe flow under realistic industrial process conditions. Well defined model suspensions were used, consisting of 11 mm and 90 mm diameter polyamide particles suspended in rapeseed oil at concentrations ranging from 1 to 25 % by volume. The variation of concentration and particle size distribution had the expected effects on the shear viscositiy of the investigated unimodal and bimodal suspensions. The in-line results showed that the investigated suspensions exhibit Sisko flow behavior and demonstrated that the UVP+PD method can be used to determine the flow behavior of complex fluids and suspensions, even at high solid concentrations, under industrial conditions in-line. The obtained inline results were in good agreement with measurement data obtained using a conventional rotational controlled- stress rheometer. Limitations of commercially available transducer technology were identified and other possible sources of inaccuracy of the UVP+PD method were investigated. Several improvements of the UVP+PD measurement method were proposed.

Cite this publication as follows:
Wiklund J, Birkhofer B, Jeelani S, Stading M, Windhab EJ: In-line rheometry of particulate suspensions by pulsed ultrasound velocimetry combined with pressure difference method, Appl. Rheol. 22 (2012) 42232.


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