Jari Hämäläinen

Interactive solution approach to a multiobjective optimization problem in a paper machine headbox design

A successful application of the interactive multiobjective optimization method NIMBUS to a design problem in papermaking technology is described. Namely, an optimal shape design problem related to the paper machine headbox is studied. First, the NIMBUS method, the numerical headbox model, and the associated multiobjective optimization problem are described. Then, the results of numerical experiments are presented.

Optimal design of paper machine headboxes

A shape optimization problem for incompressible flows within a stabilized finite element framework is studied. The goal is to develop and test numerical realizations of optimal shape design problems that could be applied to non-trivial industrial problems. The resulting algorithm is applied to the optimization of the geometry of a tapered header in a paper machine headbox. Copyright

Modelling the effect of shear flow on fibre orientation anisotropy in a planar contraction

The effect of turbulence generating vanes and its location in a planar contraction on fibre orientation anisotropy was studied by mathematical modelling. We use single phase CFD (Computational Flui ...

Mathematical modelling of moisture induced out-of-plane deformation of a paper sheet

Moisture changes in a paper sheet cause curling and cockling due to expanding or shrinking fibres. Mathematical modelling of these phenomena is considered in this paper. The paper sheet is assumed to be a heterogeneous orthotropic elastic material. Heterogeneity of the paper is handled by dividing it into small pieces, assuming one piece to be homogeneous. This leads to a mathematical model consisting of thousands of homogeneous orthotropic pieces which have different elastic properties and moisture expansion coefficients. The mathematical model is solved using the finite element method. We will show numerical examples and conclude in this paper that the elastic model is able to predict out-of-plane deformations such as cockling of the paper sheet.

Designing Paper Machine Headbox Using GA

Abstract A non-smooth biobjective optimization problem for designing the shape of a slice channel in a paper machine headbox is described. The conflicting goals defining the optimization problem are the ones determining important quality properties of produced paper: 1) basis weight should be even and 2) the wood fibers of paper should mainly be oriented to the machine direction across the width of the whole paper machine. The novelty of the considered approach is that maximum deviations are used instead of least squares when objective functions are formed. For the solution of this problem, a multiobjective genetic algorithm based on nondominated sorting is considered. The numerical results demonstrate the ability to obtain a large set of nondominated designs.

CFD-based Optimization for a Complete Industrial Process: Papermaking

Development of tailored software tools based on coupling of Computational Fluid Dynamics (CFD) with optimization is presented in this paper. In papermaking, industrial applications deal with fluid dynamics at the wet-end of a paper machine as well as in the entire papermaking process.

Industrial Applications: Challenges in Modeling and Computing

Complex industrial applications can be examined using modeling and computing even when theoretical and experimental approaches fail. Modeling and computing are rapidly developing tools for engineering and science, but applying these tools in practice is a challenge. This article focuses on industrial multi-physics and multi-scale problems in the production of silicon crystals and the design of paper machines.