Novel ultrasound based time averaged flow mapping method for die entry visualization in flow of highly concentrated shear-thinning and shear-thickening suspensions

In this work a methodology for high-resolution time averaged two-dimensional flow mapping of converging flows was explored. Flow of non-transparent, highly concentrated shear-thinning and shear-thickening suspensions was circulating through the entrance flow adapter with adjustable position of the die entry. The entrance region was scanned with the distance resolution of 2.7 mm ? 1 mm, radial to axial displacement respectively. The time averaged flow map was composed from one-dimensional flow profiles measured along the ultrasonic sensor beam using the ultrasonic pulsed echo Doppler technique. Priory to die entry visualization an investigation of flow properties was performed using a novel in-line non-invasive measuring technique. The method is based on combination of the ultrasound velocity profiler velocity monitoring and pressure difference method. The rheological flow properties were derived from simultaneous recording and on-line analysis of the velocity profiles across the tube channel and related radial shear stress profiles calculated from the pressure loss along the flow channel. For the first time the entrance flow of shear-thickening suspension could be visualized. A comparison between the flow of the investigated model suspensions was qualitatively analysed. This method gives an opportunity for time averaged flow mapping of viscoelastic and viscous, non-transparent, multiphase and highly concentrated fluids.