An amendment of rotation speed-torque transformation equation for the Herschel-Bulkley model in wide-gap coaxial cylinders rheometer.

• Analytical solution to Couette inverse problem of Herschel-Bulkley fluid was derived. • The transformation equation was validated by both computer synthesized and experimental data. • Comparison between the analytical equation and the approximation equation was conducted. The Herschel-Bulkley model is one of the most commonly used rheological models for Non-Newtonian fluids, and it has been applied to describe the non-linear rheological behavior of fresh concrete. However, because it is difficult to transform the measured rotating speed and torque data into fundamental rheological units for coaxial cylinder rheometers, only an approximate approach has been proposed for this model. In order to improve the accuracy of the solution, a new integral equation describing the torque-rotation speed of Herschel-Bulkley model was derived in this paper, and 40 sets of simulated data were used for the comparison between the two methods. The equation introduced in this study was further validated by the experimental data of SCC. The results indicated that the established solution yielded more accurate results than the approximate one. [ABSTRACT FROM AUTHOR]