Host: The Japan Society of Mechanical Engineers
Name : [in Japanese]
Date : March 06, 2021
In this study, the flow behavior of highly concentrated CNF suspensions in the shear flow was investigated with stress sweep tests. A stress-controlled rheometer was used as the experimental apparatus to induce the shear flow. Stress sweep tests were conducted after the pre-shear flow and the certain rest time. Consequently, the CNF suspensions indicated twice yielding-like behaviors. In the case of flow-reverse, the flowability was improved up to the first yielding compared to the case of flow-forward. The same behavior was observed for the other concentrations, and the yielding behavior was remarkably appeared as the concentration increased. In order to quantitatively evaluate flowability, the strain profiles up to the first yielding was approximated by exponential function. The flowability was evaluated by the exponent b, which is the slope of the approximate line. As a result, it was found that the flowability in the case of flow-reverse increased with the increasing of the stress sweep rate, while the improvement of flowability in the case of flow-forward was not observed.
