Development of mathematical model to predict vertical wicking behaviour. Part I : flow through yarn

Theoretical models have been proposed in this article (Parts I and II) to predict the vertical wicking behaviour of yarns and fabrics based on different fibre, yarn and fabric parameters. The first part of this article deals with the modelling of flow through yarn during vertical wicking, whereas the second part deals with the modelling of vertical wicking through the fabric. The yarn model has been developed based on the Laplace equation and the Hagen– Poiseuille’s equation on fluid flow; pore geometry has been determined as per the yarn structure. Factors such as fibre contact angle, number of filaments in a yarn, fibre denier, fibre cross-sectional shape, yarn denier and twist level in the yarn have been taken into account for development of the model. Lambertw, a mathematical function, has been incorporated, which helps to predict vertical wicking height at any given time, considering the gravitational effects. Experimental verification of the model has been carried out using polyester yarns. The model was found to predict the wicking height with time through the yarns with reasonable accuracy. Based on the proposed yarn model, a mathematical model has been developed to predict the vertical wicking through plain woven fabric in the second part of this article

Mathematical model to predict vertical wicking behaviour” : Part II - Flow through woven fabric

The aim of the paper is to develop a mathematical model to predict vertical wicking behaviour of woven fabric. The first part of this series (Part I) has dealt with the mathematical model for predicting vertical wicking through yarn. In this part a model has been proposed to predict vertical wicking of the woven fabric, based on the developed yarn model. In order to model the flow through woven fabric along with the vertical flow through liquid carrying threads, the horizontal flow through transverse threads has also been taken into account. A simplified fabric geometrical concept (inclined tube geometry) and Peirce geometry for plain woven fabric have been used to define the fabric structure. Warp and weft linear density, fabric sett and yarn crimp have been considered in the fabric modelling. The theoretical wicking values of the yarn and fabric made from that yarn have been compared. Experimental verification of the model has been carried out using polyester and polypropylene fabrics. The model is found to predict the wicking height with time through the yarns and fabrics with reasonable accurac

Moisture flow through blended fabrics - effect of hydrophilicity

Moisture flow through blended material is a complex phenomenon. Clothing should possess good water vapour as well as liquid moisture transmission property, for providing the thermophysiological clothing comfort. The clothing should take up the moisture from the skin as well as transmit it to the atmosphere. Higher hydrophilicity of a material is known for good absorption, but how it really helps to transmit the moisture, has been studied in the present work. Polyester and viscose have been chosen as the blending fibers and 8 fabrics with different blend proportions were developed. Water vapour transmission of the fabrics was measured using the PERMETEST. Liquid water transmission property of the fabrics was examined using a gravimetric inplane wicking tester and a vertical wicking tester. From the experimental result it has been observed that water vapour permeability and absorbency of the material increases with the increase in number of hydrophilic group in the material, but it has an adverse effect on the liquid moisture transmission behavior of the material. The vertical as well as horizontal wicking of the material decreases with the increase in viscose proportion in the polyester/viscose blended fabrics

Modeling and simulation of moisture transmission through fibrous structures – Part I: Water vapuor transmission

The moisture transmission behaviour of clothing plays an important role in determining its thermo-physiological comfort. The determination of the factors involved in moisture transmission of clothing and its prediction have become a main concern for researchers for many years. An attempt has been made to review the research studies on modelling and simulation of moisture transmission through fibrous assemblies. The review work has been divided in two parts. The first part deals with moisture vapour transmission and the second with liquid water transmission through fibrous materials. The various processes involved in water vapour transmission through fibrous materials are diffusion, absorption – desorption, convection, evaporation and condensation. The models on water vapour transmission through fibrous materials are based on the mass balance equation. Some of the studies involving theoretical work on vapour transmission have been conducted on individual processes. Others consider the inter-related effects involved. Moisture vapour transmission through textile materials is coupled with heat transfer phenomena, due to its hygroscopic nature. The atmospheric conditions, the structure of the fibrous materials and the hygroscopic nature of the fibres significantly influence the processes. Amongst the available models on vapour transmission, the model developed by Li and Zhu predicts simultaneous sheat and moisture transfer considering moisture sorption, condensation and capillary liquid diffusion in porous textiles and this model is best suited for determining textile clothing comfort.(undefined

Studies on moisture transmission properties of PV-blended fabrics

Moisture transmission properties are most important for fabric comfort.We have studied the moisture transmission properties of the plain-woven fabric produced with polyester–viscose-(PV) blended yarns. PV-blended yarns of varying blend proportion, yarn count and twist levels have been used for fabric manufacture. A three-variable Box and Behnken factorial design technique has been used to study the interaction effects of the above variables on the aforesaid characteristics of fabrics. The interactive effect of these three variables on the air permeability, water vapour permeability, in-plane wicking and vertical wicking of PV-blended fabrics has been studied and the response surface equations for all the properties have been derived; also, the design variables have been optimized for all the moisture transmission-related properties. Most of the moisture transmission characteristics were found to be affected significantly by blend proportion, count and twist levels at 95% level of significance with the present variables