Quantifying Anti Friction Lubricant Protection Limits for Elastane Cores under High Drag Jet Processing
Sustaining a 1.8 percent ester lubricant film on elastane cores prevents elastomeric rupture when jet nozzle pressure exceeds 2.2 bar.
Rope Cavitation
Fluid Turbulence
Formation and collapse of low-pressure vapor bubbles within the liquid boundary layer of rope-form fabrics processed in jet dyeing machines represents a major cause of localized fabric damage. This phenomenon, known as rope cavitation, occurs when the liquid dye liquor is forced at high speed through the machine nozzle. The resulting micro-shocks can tear fibers and create bare spots on the fabric surface.
Process Mechanics
Jet dyeing machines circulate fabric in a rope form using a high velocity stream of dye liquor. When the pump pressure is high and the nozzle design is restrictive, the risk of rope cavitation increases. The rapid collapse of the vapor bubbles generates intense localized heat and pressure that degrade the fabric.
Fabric Defects
Fabrics made from delicate or low-strength fibers are particularly vulnerable to this type of mechanical stress. The damage caused by rope cavitation appears as fuzzy patches, pilling, or uneven dye uptake in the finished fabric. These defects ruin the visual appearance of the fabric and lead to rejections.
Prevention Methods
Dye house operators minimize this issue by adjusting the liquor ratio and nozzle pressure during the dyeing cycle. By maintaining a steady flow of dye liquor and avoiding excessive pump speeds, the onset of rope cavitation is prevented. Using modern, low-stress nozzles also helps distribute the fluid force more evenly over the fabric.