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Simulation of water removal in paper based on a 2D Level-Set model coupled with volume forces representing fluid resistance in 3D fiber distribution
Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
Karlstad University, Faculty of Health, Science and Technology (starting 2013), Department of Engineering and Chemical Sciences.
(English)Manuscript (preprint) (Other academic)
Abstract [en]

A numerical model of a vacuum dewatering process was established with a Level-Set method to simulate two-phase flow in a 2-dimensional paper sheet model with constructed volume forces representing flow resistance in a 3-dimensional environment. Nine cases of various volume force representations were compared to numerical and experimental data. Based on the dry content and dwell time relation, the case with the influence of the paper/wire interface showed the most pleasing result compared to experimental data. Compared to the other numerical cases, considering the blockage of the pore space at the top layer of the forming fabric plays an essential role in determining the flow resistance during the vacuum process. Also, the dynamics of the dewatering rate is captured well with the influence of the blockage of fibers on the top layer of the forming fabric. The peak of the dewatering rate could be investigated further with a higher frequency of sample points on new experimental data.

The computational time for the two-phase flow models in this study is extensively reduced due to the removal of the internal structure. This distinction enables time efficient simulations of vacuum dewatering process in which several dewatering parameters such as level of vacuum, influence of moving vacuum pulse and higher basis weights could be investigated.

Keyword [en]
Volume force, Volume-averaging, Two-phase flow, Level-Set method, Porous media, Vacuum dewatering
National Category
Fluid Mechanics and Acoustics
Research subject
Environmental and Energy Systems
Identifiers
URN: urn:nbn:se:kau:diva-31962OAI: oai:DiVA.org:kau-31962DiVA: diva2:713702
Available from: 2014-04-23 Created: 2014-04-23 Last updated: 2014-05-19Bibliographically approved
In thesis
1. Methods for Reducing the Complexity of Geometrical Structures Based on CFD Programming: Time Efficient Simulations Based on Volume Forces Coupled with Single and Two-phase Flow
Open this publication in new window or tab >>Methods for Reducing the Complexity of Geometrical Structures Based on CFD Programming: Time Efficient Simulations Based on Volume Forces Coupled with Single and Two-phase Flow
2014 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

Throughout recent years, computer based programs have been applied to solve and analyse industrial problems encountered global fields such as automobile design for reduction of CO2-gas, designing wind parks aimed at increasing power output etc. One of these developed programs is Computational Fluid Dynamics (CFD) which numerically solves complex flow behaviour based on computer power.

As there is an ongoing expansion of CFD usage in industry, certain issues need to be addressed as they are becoming more frequently encountered. The general demand for the simulation of larger control volumes and more advanced flow processes result in an extensive requirement of computer resources. Moreover, the implementation of commercial CFD codes in small-scaled industrial companies seems to generally be utilised as a black box based on the knowledge of fluid mechanic theory. Increased partnerships between industry and the academic world involving various CFD based design processes generally yield to a verbal communication interface, which is a crucial step in the process given the level of dependency between both sides.

Based on these notions, a method for establishing time efficient CFD-models with implementation of volume forces as sink terms in the momentum equation is presented. The internal structure, or parts of the structure, in the simulation domain is removed which reduces the geometrical complexity and along with it, computational demand.  These models are the basis of assessing the benefits of utilizing a numerical based design process in industry in which the CFD code is used as a communication tool for knowledge sharing with counterparts in different fields.

Abstract [en]

As there is an ongoing expansion of CFD usage in industry, certain issues need to be addressed as they are becoming more frequently encountered. The general demand for the simulation of larger control volumes and more advanced flow processes result in an extensive requirement of computer resources. Moreover, the implementation of commercial CFD codes in small-scaled industrial companies seems to generally be utilised as a black box based on the knowledge of fluid mechanic theory. Increased partnerships between industry and the academic world involving various CFD based design processes generally yield to a verbal communication interface, which is a crucial step in the process given the level of dependency between both sides.

Based on these notions, a method for establishing time efficient CFD-models with implementation of volume forces as sink terms in the momentum equation is presented. The internal structure, or parts of the structure, in the simulation domain is removed which reduces the geometrical complexity and along with it, computational demand.  These models are the basis of assessing the benefits of utilizing a numerical based design process in industry in which the CFD code is used as a communication tool for knowledge sharing with counterparts in different fields.

Place, publisher, year, edition, pages
Karlstad: Karlstads universitet, 2014. 104 p.
Series
Karlstad University Studies, ISSN 1403-8099 ; 2014:32
Keyword
Numerical design cycle, CFD, porous media, volume forces, heat exchanger, vacuum dewatering, time efficient simulations
National Category
Fluid Mechanics and Acoustics
Research subject
Environmental and Energy Systems
Identifiers
urn:nbn:se:kau:diva-31983 (URN)978-91-7063-565-6 (ISBN)
Public defence
2014-06-09, 9C 204, Universitetsgatan 2, Karlstad, 10:15 (Swedish)
Opponent
Supervisors
Available from: 2014-05-19 Created: 2014-04-25 Last updated: 2016-10-06Bibliographically approved

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