THE HIGH SPEED SPINNING BY USING AN AIR JET NOZZLE

This report deals with an experimental investigation on the drawing method of the molten polymer of P. P. by means of an air jet nozzle. Fig. 1 is a structural diagram of the air jet nozzle, which was designed in such a way that the jet air may reach the sonic velocity at nozzle pressures above 2.18kg/cm2. The air flow below the outlet of the jet nozzle was observed by schlieren method in the form of shock waves as shown in Fig. 2. In the drawing process, considering the force balance on the running yarn at the point of jet nozzle, the fineness of the yarn should possess a limiting value. Fig. 9 shows the calculated values of the limiting fineness at various positions of the jet nozzle from the spinneret and at various air pressures in the nozzle. Fig. 10 shows the results obtained from the experimental values. These values are compared in Table 1. The load-elongation curves of the yarns are shown in Figs. 13-16, and their birefringenes (Δn) in Figs. 17 and 18.