Newsletter  2022.2  Index

Theme :"The Conference of Fluid Engineering Division (February issue)" Preface （T. Hashimoto，S. Matsuda，H.J. Park） Glimpses of Jomon lifestyle from interdisciplinary research Nobuhiko KAMIJO (Hirosaki University) Stress of needle-free injection by focused microjet and study on stability of the jet velocity using machine learning Daichi IGARASHI, Yuta Miyazaki, Masashi USAWA, Shuma KAWAI, Jingzu YEE, Masakazu MUTO, Shoto SEKIGUCHI, Yoshiyuki TAGAWA (Tokyo University of Agriculture and Technology) Numerical Simulation on Nano Fibril Orientational Control by Electric Field in Cellulose Dispersed Flow Takumi USUI (Tohoku University), Hidemasa TAKANA (Tohoku University) Evaluation of Particle Behavior in Radial Turbine for Marine Turbocharger Based on Lagrangian Particle Tracking Model Nao TANIGUCHI, Fumito HIRATANI (MITSUBISHI HEAVY INDUSTRIES, LTD.), Takeshi TSUJI and Hidetaka NISHIMURA (Mitsubishi Heavy Industries Marine Machinery & Equipment, Ltd.) Diary of Flow Sommelier and Sound Sommelier Mari Kasai (Hokkaido University)

 

Numerical Simulation on Nano Fibril Orientational Control by Electric Field in Cellulose Dispersed Flow

Takumi USUI (Tohoku University), Hidemasa TAKANA (Tohoku University)

Abstract

Cellulose Nano-fibrils (CNFs) are the fundamental building blocks of wood and paid special attentions because of their outstanding mechanical and thermal properties. The mechanical properties of cellulose filament made of CNFs can be improved by their orientation control. In this study, the complex behavior of CNFs in the elongational flow and electric fields were clarified by solving the equation of motion for individual CNFs. Without applied electric field, the CNF orientation degree increases at the flow focusing section by the sheath flow. This is due to the enhanced alignment by the shear and elongation effects. The longer the CNFs are, the higher alignment can be realized in the downstream of the flow focusing section. With electric field applied, shorter CNFs show higher response to the electric field, and the orientation degree increases linearly in the electric field region. In the case of 600 nm, orientation degree was improved by 25.7 % with electric field assisted alignment, although the orientation degree decreases rapidly due to the predominant Brownian rotation in the downstream of electric field region before the sheath injection. The enhancement of CNF alignment by electric field can be shown independent of CNF length. Even for short CNFs, approximately the same orientation degree was obtained as that of longer CNFs without electric field.

Key words

Cellulose nano-fibril, Numerical simulation, Orientation control, Elongational flow, Electric field, flow focusing

Figures

Figure 1  Volume fraction of CNF dispersion in flow-focusing channel.

Movie 1  Visualization of fiber alignment by electric and flow fields (V = 600V, l = 900 nm).

Figure 2  Effect of applied electric field on CNF alignment for (a) V = 0 V and (b) V = 600 V.