Simulation of Unconventional Resonator Cavity Geometries for a Novel and Efficient Microwave-Based Heating Method in False-Twist Texturing

Abstract

Melt-spun man-made fibres are crucial for the ever-rising demand for fibres. To use them in clothing or home textiles, they need the feel and properties of natural fibres, often imparted through texturing processes. The most dominant process, with 30 Mio. t production capacity per year, uses false-twist texturing to smooth melt-spun partially oriented yarns (POY) into crimped, fluffy draw-textured yarns (DTY). However, the heaters used in the process are long and inefficient, thereby compromising production efficiency. Short, efficient microwave heaters are proposed to overcome these drawbacks, reducing energy consumption by 40 % and increasing productivity by 20 %, leading to significant cost savings and equivalent CO₂ reductions during DTY production. However, conventional microwaves do not reach peak electric field strengths needed to heat the yarns in such a short residence time. Therefore, an optimisation algorithm is developed that couples a Genetic Algorithm and a high-frequency simulation to identify an unconventional microwave resonator geometry with high electric field strengths along the yarn path of polymeric multifilament yarns. First results show promising process behaviour and industrial yarn qualities. Future work will quantify energy efficiency and validate on a pilot scale along with a novel yarn temperature sensor.