Thesis Details


Thesis Title: Development of heat transfer models and comparisons of primary heaters for false-twist texturing of polyester
Thesis Author: Stephen Lucas
Abstract: Heat history of synthetic yarn dictates important properties including dyeability and bulk. In the false-twist texturing process, the application of heat to the filaments is also a major parameter that controls yarn and fabric properties. To achieve and maintain the desired bulk of a textured yarn, the yarn temperature must be raised to the correct level in the texturing process. Heat transfer models have been published for heaters with a single zone primary heat, but little has been published on heat transfer models for two-zone primary heating. Also, little has been published on the comparison of yarn properties for different texturing heater types using different deniers and filament counts. Heat transfer models relating various machine setting parameters and raw yarn properties are invaluable when setting up texturing machines to produce high quality textured yarns. Therefore, in this study, heat transfer models were developed using thermodynamic principles. These models were found to accurately predict yarn temperature using machine setting parameters and raw yarn properties. This study determined the effects of various heater constructions. A 2.5-meter conventional contact heater and two different I.O-meter high temperature heaters were used. The heaters had geometrical differences as well as temperature ranges, which affected heat transfer and, consequently, were found to affect yarn tensions and dye uptake. Yarn properties such as textured yarn denier, tenacity, and elongation were significantly affected by differences in machine manufacturing settings. Power consumption was also found to be lower for the 2.5-meter heater than the I.O-meter heater.