Flow Characteristics of Pulp Suspension in a 90º Bend

• Published in: International journal of fluid machinery and systems pp. 425 - 436
• Main Authors: Masaru Sumida, Kentaro Imamura
• Format: Journal Article
• Language: English
• Published: 한국유체기계학회 01.06.2020
• Subjects: 기계공학
• ISSN: 1882-9554
• DOI: 10.5293/IJFMS.2020.13.2.425

This study investigates the flow characteristics of pulp suspensions flowing through a 90 bend, which is used in the production system of an actual papermaking machine, e.g., for transporting the pulp suspensions from its stock reservoir to the header. Experiments were conducted on pulp suspensions with a fiber concentration C s of 0.3 and 0.6 wt% and a bend with a diameter of 22 mm and a curvature radius ratio of 4.0. Flow visualization and measurements of the distributions of time-averaged fiber concentration C a and axial velocity U were performed with a light section method and the particle image velocimetry (PIV) method, respectively, at representative bulk velocities and at various longitudinal stations. The influence of the flow rate on the changes of their distributions in the streamwise direction was examined. The flow characteristics of the pulp suspension depend on the flow pattern in the upstream straight tube and are greatly different from those of the single-phase water flow. For a low flow rate, the flocculated pulp fibers move without getting disentangled in the bend and the distribution of C a shows a shape bias towards the inner wall side. As the flow rate is increased, C a becomes larger in the outer part of the bend, and it changes into a rather flat distribution in the downstream tangent. KCI Citation Count: 0