The article concerns the widespread issue of thermal comfort; investigations into textiles and thermal insulation problems are presented. Materials that were tested include double-layer knitted fabrics with potential application in multi-layer garments addressed to a specific group of users. The investigated materials were constructed with the following raw materials: cotton, polypropylene, polyester, polyamide, bamboo, and viscose. The textiles with a comparable geometric structure and different composition were tested for their thermal insulation. In the experimental section the temperature gradients in specific constant ambient conditions using a thermal imaging camera were obtained. In the simulation section three-dimensional models of actual textiles were designed and the temperature gradients on the basis of performed simulations were calculated. Both measurements and simulations yielded comparable results and showed that the comparatively thick knitted fabrics’ thermal insulation strongly depends on the raw materials from which they were made and less on the parameters of the yarn.

Studies presented in this paper concern wide issue of thermal comfort of protective clothing. The Computer Aided Design (CAD) software tools to analyze thermal insulation of multilayer textile assembly used in thermal protective clothing were applied. First, 3D geometry and morphology of a real textile assembly was modeled. In the designed model different scales of resolution were used for individual layers, ranging from a homogenized nonwoven fabrics model to mapping the geometry of yarns in woven fabrics model. Next, the finite volume method to estimate thermal insulation properties of this assembly, when exposed to heat radiation, was used. Finally, the simulation results were verified experimentally using method described in EN ISO 6942. On the basis of both simulation and experimental results obtained for the multilayer textile assembly, protective clothing parameters directly affecting the ability to protect against heat, were determined. Correlating simulated and experimental values of these parameters were obtained, which may indicate that applied software can be an effective tool in analyzing thermal properties of newly designed multilayer functional clothing.

The paper concerned the issue of ergonomics and thermal comfort of footwear. The presented work was an attempt to apply selected modeling CAD software and the finite volume method for analysis of heat transfer through footwear between the shoes' user and his surroundings. Based on the actual two selected sport shoes, three-dimensional models have been designed, taking into account their different geometry and raw material composition. The models used simplifications related to the internal construction (in microscale) of the specific parts of the footwear (sole, insole, shank, lining and tongue). The main purpose of the work was to determine the influence of the simplifications used on the accuracy of simulation as a tool to predict thermal insulation of real shoes determined by means of thermal imaging camera. The simulations results were in correlation with the experiment and showed that applied software can be an effective tool in studying the thermophysiological properties of footwear.

This article concerns the widespread matter of biophysical comfort. In this work, 10 double-layer knitted fabrics with potential application in multilayer garments addressed to a specific group of users, such as newborns, were investigated. The materials were constructed with the following raw materials: cotton, polypropylene, polyester, polyamide, bamboo, and viscose. The textiles with a comparable geometrical structure and different composition were tested for their air permeability. In the experimental part, the materials were tested in specific constant ambient conditions using an air permeability tester. In the simulation part, 3D models of actual textiles were designed and air permeability based on the performed simulations using finite volume method was calculated. Both measurements and simulations yielded comparable results and showed that the air permeability of the knitted fabric strongly depends on the thickness and geometrical parameters of yarn. Figure 15. The influence of the thickness of the knitted fabric on air velocity (determined experimentally and by simulation); broken curves guide the eye.

The main goal of the current work is to analyse the three-dimensional approach for modelling knitted fabric structures for future analysis of physical properties and thermal phenomena. The introduced model assumes some simplification of morphology. First, fibres in knitted fabrics are described as monofilaments characterized by isotropic thermal properties. The current form of the considered knitted fabric is determined by morphological properties of the used monofilament and simplification of the stitch shape. This simplification was based on a particular technology for the knitting process that introduces both geometric parameters and physical material properties. Detailed descriptions of heat transfer phenomena can also be considered. A sensitivity analysis of the temperature field with respect to selected structural parameters was also performed.

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The article concerns the wide issue which is thermal comfort. In the paper investigations on the textile thermal insulation problem are presented. Materials tested were multi-layer systems with potential application in uniforms addressed to firefighters. Thermal insulation was tested both experimentally (using a thermal imaging camera) and by modelling (by means of simulations of heat transfer phenomena on 3-D models of real textiles). The materials investigated were constructed with the following raw materials: Kevlar, Nomex, ePTFE, PU and carbon fiber. Textiles with a comparable geometric structure and similar composition were tested for their thermal insulation. In the experimental part temperature, the change in specific constant ambient conditions was obtained using a thermal imaging camera. In the simulation part 3-D models of actual textiles were designed and the temperature change was calculated on the basis simulations of the real experiment performed. For each multi-layer system two models were designed, with varying degree of mapping the structure of the yarn in the fabrics. The main goal of the work was experimental verification of both models. As a result of the simulation performed on a model characterised by a more accurate mapping of the yarn structure, comparable results were obtained with experimental data and a strong relationship of thermal insulation textiles from the composition of raw materials and the geometric structure was confirmed.

The article presents the results of an attempt to use high-resolution X-ray micro-computed tomography (micro-CT) to model the thermal insulation of clothing as one of the most important parameters affecting the heat balance between a human and his/her surroundings. Cotton knitted fabric applied in functional clothing for newborns and aramid woven fabric used in multilayer protective clothing for firefighters were the tested materials. The 3D models of real textiles based on micro-CT images were developed. Next, the models were applied to heat transfer simulations using the finite volume method. The usefulness of the models was experimentally verified using thermography with real textiles. The simulation results were consistent with the measurement results and confirmed the relationship between the thermal insulation and geometry of the textiles on the one hand and the physical parameters of the raw materials from which they were made on the other hand.