AIR DRAG IN HIGH SPEED MELT SPINNING

Measurements of air drag on spinning filaments at take-up speeds of up to 6, 000 m/min are reported. Air drag on filaments can be expressed as a function of the diameter-based Reynolds number: K value lies in the region of 0.23-0.49 for filaments spun into still air and 0.77 for filaments spun into axisymmetric air stream. K value strongly depends on the filament vibration and on the filament spacing in the spinline.Air drag (σair) and inertia (σin) contributions to the spinning stress are predominant in high speed melt spinning and hence, the spinning stress (σL) can be simply expressed as From this simple equation, air drag coefficients (namely n and K in the form of ) can be determined by conventional means and the solidification distance from the spinneret can be roughly estimated.