2024 Student Poster Award - 2nd Place

A novel calibration procedure for orthogonal superposition measurements

1. Waeterloos, Jarno L. (KU Leuven, Chemical Engineering Department)
2. Clasen, Christian (KU Leuven, Chemical Engineering Department)

Abstract

Many materials undergo transient microstructural evolutions when subjected to steady shear flows. Measurement methodologies include subjecting the material to a steady shear while simultaneously applying an oscillation either in the mutual direction (parallel superposition - PSP) or in the perpendicular direction (orthogonal superposition - OSP). While PSP has the disadvantage of coupled flow fields leading to convoluted results, OSP can easily be used to gain insight into the material behavior under flow and serves as a framework for the development of novel methods. Although both techniques are commercially available for the TA ARES-G2 rheometer, the calibration of such setups has received little attention to enable proper accuracy over the whole frequency range. Traditionally, the rheometer parameters are determined using suspended weights or calibrated springs and the results are fitted to a mass-spring-damper differential equation [1]. Effects from the slotted orthogonal double-walled Couette are corrected by so-called end-factors [2].