Integral Flow Parameters and Material Characteristics Analysis in Through Air Drying: Part I

Abstract

The extension of the Darcy law (the Forchheimer flow equation) relating second-order nonlinear pressure drop with flow velocity is studied during fast transient through air drying of sheets of porous biobased materials such as paper. A range of the paper materials with open structure consistent with tissue and towel products (basis weights 25 and 50 g/m²) made using different production processes are analyzed for the factor-specific influences with regard to changes in the fluid resistance from the removal of moisture from the material interstices. A characteristic dimension suitable for the drying process is applied from viscous and inertial momentum transport analysis.

Keywords:

• Forchheimer equation
• Inertial term
• Paper
• Through air drying
• Viscous term

ACKNOWLEDGEMENT

The authors express their sincere gratitude to Prof. Terrence Simon from the Department of Mechanical Engineering, University of Minnesota, and Dr. G. Worry of Georgia Pacific Corporation for research project support/funding.