Mixing Intensity Analysis of a 2-Layer Stratified Headbox Jet, 2000 Engineering Conference Proceedings

Alfred C. Li, Thomas D. Rogers, Jay A. Shands--The mixing characteristics of a water jet as a function of the free jet distance from a stratified 2-layer headbox nozzle have been studied. The experimental technique used in this work involves the introduction of salt water into the top layer and then measuring the z-direction profile of the fluid conductivity at various points along the free jet. By incorporating a statistical model, the overall mixing characteristics are quantified in terms of a single parameter, IMH, which represents the mixing intensity at a specific machine direction location in the free jet. From the mixing intensity data, it is apparent that IMH increases with the distance from the slice, and is inversely affected by slice opening and headbox flowrate. In general, a shorter divider sheet stickout tends to provide a lower degree of mixing, but a longer divider sheet stickout may be preferable in certain specified cases. These results are consistent with that found in the previous 3-layer studies. The mixing intensity analysis on the sheet sample has been performed to identify the significance of the headbox influence relative to the rest of the forming system.