Fibre Orientation and Related Headbox Optimization Systems Headbox Optimization Systems Jari Hämäläinen C t fC t ti lE i i dIt tdD i (CEID) Centre of Computational Engineering and Integrated Design (CEID) Lappeenranta University of Technology (LUT) Lappeenranta, Finland
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Fibre Orientation and Related Headbox Optimization SystemsHeadbox Optimization Systems
Jari Hämäläinen
C t f C t ti l E i i d I t t d D i (CEID)Centre of Computational Engineering and Integrated Design (CEID)Lappeenranta University of Technology (LUT)Lappeenranta, Finland
Fibre OrientationFibre Orientation
− Basic fibrous structure of the paper sheet is formed at the wet end of a paper machine -headbox and forming section
− Fibre orientation (angle and anisotropy) determines the dimensional stability of the paperdetermines the dimensional stability of the paper
− Velocity gradients align fibres whereas turbulence makes orientation more random
Nancy, 13-14 October, 2011 2www.lut.fi/ceid
Fibre Orientation, its Anisotropy d CD A l P filand CD Angle Profile
− Fibre orientation distribution in each location
− The average fibre orientation angle profile in cross direction (CD) of a paper machine
Nancy, 13-14 October, 2011 3www.lut.fi/ceid
Modelling of Fibre Orientation P b bilit Di t ib ti (FOPD)Probability Distribution (FOPD)
J/W=0.9(d )(drag)
J/W 1 1J/W=1.1(rush)
J/W=1.0(“tasaperä”)
J=Jet speedW=wire speed
Nancy, 13-14 October, 2011 www.lut.fi/ceid 4
Niskanen, Hämäläinen (2011), NPPRJ (in press)
CFD-based Optimization for Fib O i t ti A l P filFibre Orientation Angle Profiles
− Optimal shape design of the tapered header to get even flow distribution
− Optimal control of the slice opening to avoid CD velocities in the jet
− Based on depth-averaged NS equations
Nancy, 13-14 October, 2011 5www.lut.fi/ceid
− Software tools developed to industry
HOC SoftwareHOC Software
Step 2. CorrectionStep 1. Identification
Input:Measured fiberorientation profile
Result:Optimizedfiber orientation
orientation profile
HOC identification: I t
HOC correction:Slice openingcorrection
HOC identification:The correspondingflow conditions
References and Acknowledgementse e e ces a d c o edge e ts
− Fibre Orientation Probability Distribution (FOPD) modelling( ) ( )− Doctoral theses by T. Hämäläinen (2008) and H. Niskanen (2011)
− Niskanen et al., IJMF (2011)− Hämäläinen et al., J.Eng.Math. (2011)− Niskanen Hämäläinen NPPRJ (in press)Niskanen, Hämäläinen, NPPRJ (in press)− Other authors from KTH, UBC, etc.
− CFD-based Optimization− Hämäläinen et al. in “Optimization and Computational Fluid
D i ” Th i J i (2008)Dynamics”, Thevenin, Janiga (2008)− Avikainen et al., NPPRJ (2010)
− AcknowledgementsAcknowledgements− CFD-based optimization software tools have been developed since
1995 at University of Jyväskylä, VTT, Metso (Valmet) and Numerola− Thanks to Paper Physics Group at University of Eastern Finland,
Kuopio for the results of FOPD modelling in 2004 2011Kuopio for the results of FOPD modelling in 2004-2011