Characterization of the Mixing in the Headbox Jet, 2012 PaperCon Conference

Please Note: This document will be available in PDF format in the "My Electronic Documents" link on the home page once your order has been completed. Please make sure you have the latest version of Acrobat Reader. Click on the Acrobat Reader icon to check for the latest version, it’s FREE. To print a hardcopy of a PDF file correctly you must have a postscript printer. If you are not sure if your printer is a postscript printer please refer to your owner’s manual.

Purchase of electronic (downloadable) documents made at www.tappi.org by credit cards, followed by instant download CANNOT be cancelled. We do not offer refunds on electronic download documents.

Strong effects on sheet formation are normally attributed to effects of turbulence in the headbox and in the headbox jet. However, the presence of turbulent mixing in the headbox and jet can and has been disputed. In order to try to quantify these effects experiments have been performed in free jet trials, during which salt was added locally inside the headbox using the Aq-vane technique developed at Innventia for stratified forming.Strong effects on sheet formation are normally attributed to effects of turbulence in the headbox and in the headbox jet. However, the presence of turbulent mixing in the headbox and jet can and has been disputed. In order to try to quantify these effects experiments have been performed in free jet trials, during which salt was added locally inside the headbox using the Aq-vane technique developed at Innventia for stratified forming. The Aq-vane technique allows dosage of material and chemical additives through a hollow vane mounted inside the headbox and is therefore suited for adding tracer particles and e.g. salt. Visualizations of the flow have been per-formed as well as time resolved measurements using a conductivity probe that was traversed across the thickness of the jet ejected from the contraction at several downstream positions. The Aq-vane technique allows dosage of material and chemical additives through a hollow vane mounted inside the headbox and is therefore suited for adding tracer particles and e.g. salt. Visualizations of the flow have been per-formed as well as time resolved measurements using a conductivity probe that was traversed across the thickness of the jet ejected from the contraction at several downstream positions.