Expermental and mathematical modeling of flow in headboxes
department or school: Applied Science, Faculty of
department or school: Mechanical Engineering, Department of
data provider: DSpace
degree campus: UBCV
creator: Shariati, Mohammad Reza
issued: 2009-11-12T04:41:47Z
issued: 2002
related degree: Doctor of Philosophy - PhD
degree grantor: University of British Columbia
description: The fluid flow patterns in a paper-machine headbox have a strong influence on the quality of the paper produced by the machine. Due to increasing demand for high quality paper there is a need to investigate the details of the fluid flow in the paper machine headbox. The objective of this thesis is to use experimental and computational methods of modeling the flow inside a typical headbox in order to evaluate and understand the mean flow patterns and turbulence created there. In particular, spatial variations of the mean flow and of the turbulence quantities and the turbulence generated secondary flows are studied. In addition to the flow inside the headbox, the flow leaving the slice is also modeled both experimentally and computationally. A Plexiglas scaled-down model of a headbox was constructed and LDV measurements of mean and turbulence velocities in the model were made. The numerical models used in Computational Fluid Dynamics (CFD) simulations were based on finite volume Reynolds-averaged equations and included turbulence representations with the standard k-e model, quadratic and cubic algebraic turbulence models and the Reynolds stress model (RSM). The "volume of fluid" method was used to model the free surface of the jet leaving the slice. The CFD investigation showed that the turbulence generated secondary flows in the headbox are much smaller than previously thought and that they are confined to a very small region close to the wall. Comparison of the experimental and numerical results indicated that streamwise mean components of the velocities in the headbox are predicted well by all the turbulence models considered in this study. However, the standard k-e model and the algebraic turbulence models fail to predict the turbulence quantities accurately. Standard k-e model also fails to predict the direction and magnitude of the secondary flows. Inaccuracies in the numerical prediction of turbulence quantities increase as the contraction ratio increases. This…
aggregated CHO: https://circle.library.ubc.ca/rest/handle/2429/14824
extent: 14554458 bytes
format: application/pdf
note: EXPERIMENTAL AND MATHEMATICAL MODELING OF FLOW IN HEADBOXES By Mohammad Reza Shariati B. Eng. D.M.E.T. College, Calcutta, India 1988. M.A.Sc. (Mechanical Engineering) Technical University of Nova Scotia 1995. A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIRMENT FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES DEPARTMENT OF MECHANICAL ENGINEERING We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA 2002 © Mohammad Reza Shariati In presenting this thesis in partial fulfillment of the requirements for an advanced degree at the University of British Columbia, I agree that the library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the head of my department or by his or her representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of Mechanical Engineering The University of British Columbia 2324 Main Mall Vancouver, BC Canada V6T 1Z4 Date: March 2003 Abstract The fluid flow patterns in a paper-machine headbox have a strong influence on the quality of the paper produced by the machine. Due to increasing demand for high quality paper there is a need to investigate the details of the fluid flow in the paper machine headbox. The objective of this thesis is to use experimental and computational methods of modeling the flow inside a typical headbox in order to evaluate and understand the mean flow patterns and turbulence created there. In particular, spatial variations of the mean flow and of the turbulence quantities and the turbulence generated secondary flows are studied. In addition to the flow inside the headbox, the flow leaving the slice is also modeled both experimentally and computationally. A Plexiglas scaled-down model of a headbox was constructed and LDV measurements of mean an…
has type: Thesis/Dissertation
date issued: 2003-05
is shown at: 10.14288/1.0081041
language: eng
degree discipline: Mechanical Engineering
provider: Vancouver : University of British Columbia Library
publisher: University of British Columbia
rights: For non-commercial purposes only, such as research, private study and education. Additional conditions apply, see Terms of Use https://open.library.ubc.ca/terms_of_use.
scholar level: Graduate
type: Text
identifier URI: http://hdl.handle.net/2429/14824