The influence of forming surface on the vacuum pressure in hydroentangling process

Hydroentangling is a process that uses waterjet curtains issued from a series of parallel jet-heads (manifolds) for entangling and interloping fibres in a loose fibre web carried on a belt or perforated surface. The efficient removal of the stagnant water remaining from each waterjet curtain is crucial for the success of fibre entanglement when the web reaches the next jet-head. In this article, we discuss different methodologies that can be used to calculate the minimum vacuum pressure required for extracting the hydroentangling water from non-woven fabrics. A distinction has been made between hydroentangling on tightly and openly woven screens and different modelling strategies are recommended for each. In particular, it is demonstrated that a one-dimensional flow pattern coupled with available analytical permeability expressions can be used to predict the required vacuum pressure in the case of tightly woven screens. In the case of open woven screens where the flow pattern becomes three-dimensional, numerical simulation is needed for calculating the vacuum pressure required for complete removal of hydroentangling water. We also demonstrated that the vacuum pressure increases by decreasing the fibre diameter or increasing the fabrics' solid volume fractions.

[1]  M. M. Tomadakis,et al.  Viscous Permeability of Random Fiber Structures: Comparison of Electrical and Diffusional Estimates with Experimental and Analytical Results , 2005 .

[2]  W. Hsieh,et al.  Measurement and correlation of hydraulic resistance of flow through woven metal screens , 2005 .

[3]  B. Pourdeyhimi,et al.  A study on flow through hydroentangling nozzles and their degradation , 2006 .

[4]  S. Patankar.  Numerical Heat Transfer and Fluid Flow , 2018, Lecture Notes in Mechanical Engineering.

[5]  E. Dendy,et al.  A computational evaluation of the Ergun and Forchheimer equations for fibrous porous media , 2001 .

[6]  C. F. White.  Hydroentanglement technology applied to wet-formed and other precursor webs , 1990 .

[7]  H. Tafreshi,et al.  Simulating and Characterizing Water Flows Inside Hydroentangling Orifices , 2003 .

[8]  Simulating the Flow Dynamics in Hydroentangling Nozzles: Effect of Cone Angle and Nozzle Aspect Ratio , 2003 .

[9]  B. Pourdeyhimi,et al.  A study on hydroentangling waterjets and their impact forces , 2006 .

[10]  M. I. Stationwala,et al.  Pulp grinding : a new method for producing mechanical pulp , 1990 .

[11]  D. Wilcox.  Turbulence modeling for CFD , 1993 .

[12]  Weeratunge Malalasekera,et al.  An introduction to computational fluid dynamics - the finite volume method , 2007 .

[13]  T. J. Connolly,et al.  Influence of specific energy on the properties of hydroentangled nonwoven fabrics , 1993 .

[14]  B. Pourdeyhimi,et al.  Simulating Cavitation and Hydraulic Flip Inside Hydroentangling Nozzles , 2004 .

[15]  B. Pourdeyhimi,et al.  The effects of nozzle geometry on waterjet breakup at high Reynolds numbers , 2003 .