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Optimization and Computational Fluid Dynamics - Department of ...

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Chapter 9<br />

CFD-based <strong>Optimization</strong> for a<br />

Complete Industrial Process:<br />

Papermaking<br />

Jari Hämäläinen, Taija Hämäläinen, Elina Madetoja <strong>and</strong> Henri<br />

Ruotsalainen<br />

Abstract Development <strong>of</strong> tailored s<strong>of</strong>tware tools based on coupling <strong>of</strong> <strong>Computational</strong><br />

<strong>Fluid</strong> <strong>Dynamics</strong> (CFD) with optimization is presented in this paper.<br />

In papermaking, industrial applications deal with fluid dynamics at the<br />

wet-end <strong>of</strong> a paper machine as well as in the entire papermaking process.<br />

First, the CFD tools being developed for optimal shape design <strong>and</strong> optimal<br />

control problems at the wet-end (where the paper web is formed) are<br />

presented. Different levels <strong>of</strong> complexity <strong>of</strong> CFD modeling <strong>and</strong> a dimension<br />

reduction technique are considered in this paper. The reduced CFD model<br />

used is validated with a complete model.<br />

In addition, optimization <strong>of</strong> the whole papermaking process being modeled<br />

with different modeling techniques is considered. Our approach is based<br />

on interactive multi-objective optimization because the papermaking process<br />

as well as the produced paper require multiple criteria to be optimized<br />

simultaneously. Typically, the objectives are conflicting which means that<br />

compromises need to be done. This is illustrated with numerical examples.<br />

Finally, a completely new design <strong>of</strong> decision support tools based on multiobjective<br />

optimization <strong>and</strong> multiphysical modeling <strong>of</strong> large industrial systems<br />

is discussed.<br />

9.1 Introduction<br />

Optimal shape design is the best-known example <strong>of</strong> model-based optimization<br />

in which the model is described as a system <strong>of</strong> partial differential equations.<br />

In a sense, optimal shape design is an inverse problem, that is, the<br />

Jari Hämäläinen · Taija Hämäläinen · Elina Madetoja · Henri Ruotsalainen<br />

<strong>Department</strong> <strong>of</strong> Physics, University <strong>of</strong> Kuopio, P.O.Box 1627, FI-70211 Kuopio, Finl<strong>and</strong><br />

(e-mail: jari.hamalainen@uku.fi,taija.hamalainen@uku.fi,elina.madetoja@uku.fi,<br />

henri.ruotsalainen@uku.fi)<br />

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