New use heat transfer theories for the design of heat setting machines for precise post-treatment of dyed fabrics

Abstract

Fabrics are needed further treatment after dyeing to restore their original mechanical properties by suitable drying/shrinkage process because of wetted and elongated fabrics cannot be used for clothes making. Heating up the dyed fabrics at suitable temperature can restore their original shapes and geometries by releasing the internal stress introduced by dyeing process. Thus, heat setting is a commonly used post-treatment process to stabilize fabric geometrical dimensions and prevent further shrinkage. Hot air jet impingement [1] and moist heat are conventional drying methods for different applications. Despite the well establishments of these drying technologies, most of the applications are for materials like clay and paper, and few on the study of textile materials. In fact that most of the developed heat setting machines used in textile industry are only designed by empirical models and lack of theoretical bases. This situation will obstruct further improvement of the drying technology. In this paper, a theoretical basis heat transfer model is developed for a precise description of a heated air flowing process for heat setting machine design. In the machine design, a better airflow circulation strategy for an efficient drying is addressed. Equations for heat and mass transfer in moist porous materials and theories on thermo- and fluid-dynamics are used to support the machine design. Outcomes from the research are to develop a heat transfer model that provides more precise and effective calculation for heat setting machine design that unavailable from the developed machine prototypes. © (2011) Trans Tech Publications.