Probability of jet roping in solution blowing of multiple jets

Abstract

AbstractThis study describes the development and implementation of a lab‐scale four‐needle nosepiece for solution blowing, which enabled the investigation of the roping probability of four polymer jets at different inter‐needle distances and air velocities. The roping probabilities of the four jets were compared to the corresponding roping probabilities of two jets previously established by the present group. The comparison revealed that at the relatively low air velocities (pressures), the four‐jet configuration reduces roping relative to the two‐jet case, which stems from the reduction of the end effect. However, at relatively high air velocities (pressures), turbulent pulsations in the surrounding air become more dominant than the end effect. Accordingly, the four‐jet case reveals a higher probability of roping at higher air velocities (pressures). The findings shed light on the behavior of multiple solution‐blown jets and the impact of the end effect on roping. The severity of roping in the case of four jets at diminishing inter‐needle distances and increasing air velocity was analyzed using recordings of polymer jets in flight by a high‐speed camera and scanning electron microscopy of the corresponding laydown structure.