Increasing the drying efficiency of cylinder drying

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Show simple item record Keränen, Janne 2012-01-12T12:11:41Z 2012-01-12T12:11:41Z 2011
dc.identifier.isbn 978-951-39-4590-9
dc.identifier.issn 0075-465X
dc.identifier.uri en
dc.description.abstract This PhD Thesis concentrates on paper drying: first on the drying rate in a cylinder covered with fabric, enhanced using hot air impingement through the fabric, and its potential effects on paper quality, and second, on the heat transfer rate from hot steam to paper through the cylinder shell. Cylinder drying is a drying method where a heated surface in contact with paper causes water removal from the latter by evaporation. Impingement through the fabric of hot air has been suggested to cause increase in the water removal and drying of paper. Increase in the drying rate by impingement of hot air was confirmed by laboratory tests and by simulations. In laboratory tests the increase in the drying rate was found to be accompanied by improvements in paper quality. The reason for the unexpectedly high increase in the case of combined cylinderimpingement drying of the drying rate was traced down to decrease in the temperature of paper. The thereby increased temperature gradient between paper and cylinder surface caused an increase in the heat flux from the cylinder. A simulation model for the system showed similar increase in the drying rate of paper. Simulations could also be extended to a paper machine scale. Use of the simulation model required further work on the experimental transport of moisture in the thickness direction of paper, with successful results. The potential of impingement drying for improving paper quality was demonstrated, especially for prevention of shrinkage of paper during drying. Shrinkage prevention has a positive influence on the tensile properties of paper. Shrinkage prevention still needs verification in a larger scale, however. fi
dc.format.extent verkkoaineisto (80 sivua).
dc.language.iso eng
dc.publisher University of Jyväskylä
dc.relation.ispartofseries Research report / Department of Physics, University of Jyväskylä no. 14/2011.
dc.relation.isversionof ISBN 978-951-39-4589-3
dc.rights openAccess fi
dc.subject.other paper drying
dc.subject.other moisture gradient
dc.subject.other simulation
dc.subject.other cylinder drying
dc.subject.other impingement drying
dc.subject.other heat transfer
dc.subject.other cylinder shell
dc.title Increasing the drying efficiency of cylinder drying
dc.type Diss. fi
dc.identifier.urn URN:ISBN:978-951-39-4590-9
dc.subject.ysa kuivaus
dc.subject.ysa paperinvalmistus
dc.subject.ysa vesipitoisuus
dc.subject.ysa mallintaminen
dc.subject.ysa simulointi
dc.subject.ysa lämmön siirtyminen
dc.subject.ysa sylinterit
dc.subject.kota 114
dc.type.dcmitype Text en
dc.type.ontasot Väitöskirja fi
dc.type.ontasot Doctoral dissertation en
dc.contributor.tiedekunta Matemaattis-luonnontieteellinen tiedekunta fi
dc.contributor.tiedekunta Faculty of Mathematics and Science en
dc.contributor.yliopisto University of Jyväskylä en
dc.contributor.yliopisto Jyväskylän yliopisto fi
dc.contributor.oppiaine fysiikka fi

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