Structure optimization of separating nozzle for waste plastic recycling

Abstract The wide application of plastic products had led to a large amount of waste plastics, which brought serious environmental pollution problems. Although separation is the first step of waste plastic recycling, the injection separating device is still not fully optimized. In this paper, the influences of nozzle outlet diameter, contraction ratio, length of contraction section, total length of nozzle, and distance between two nozzles on plastic separating device were systematically simulated and analyzed using computational fluid dynamics (CFD) software. Based on the Witozinsky curve, the optimal parameters combination of nozzle outlet diameter, contraction ratio, length of contraction section, and distance between two nozzles were found to be 6 mm, 1.6, 4 mm, and