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Your search keyword '"THERMAL properties"' showing total 2 results
Start Over Descriptor "THERMAL properties" Topic thermal analysis Publication Year Range This year Publisher emerald publishing limited
2 results on '"THERMAL properties"'

1. Effect of layering outerwear on innerwear and air gap between the two layers on thermal comfort properties of knitted fabrics.

Author

Kammeta, Meghana and Palaniswamy, N.K.

Subjects
THERMAL conductivity, THERMAL properties, SUMMER, THERMAL analysis, OUTDOOR clothing, THERMAL resistance, THERMAL comfort
Abstract

Purpose: In everyday life, people generally wear two layers of clothes (a knitted vest and a knitted t-shirt) during the summer. It is essential to understand which types of innerwear and outerwear maximize comfort. The primary objective of this research is to investigate the influence of layering outerwear on innerwear, as well as the air gap between two layers, on thermal comfort properties. Design/methodology/approach: In this study, a total of 12 combinations were created from four vest fabrics and three T-shirt fabrics. The thermal properties (thermal conductivity, thermal resistance, thermal absorptivity, thermal diffusion and peak heat flow) were evaluated for the individual inner and outer layers. Each inner layer was layered with an outer layer to observe the effect of layering on the thermal properties. An air gap of 2 mm was introduced between the inner and outer layers to study the effect of air gap on thermal properties. Findings: Tencel fibre exhibits higher thermal conductivity and absorptivity than cotton and polyester. Upon layering an outer layer on an inner layer, the thermal conductivity and thermal absorptivity increase to a slight extent, thermal resistance and diffusion increase drastically and the peak heat flow reduces. With an air gap between the two layers, the thermal conductivity did not improve, the difference in thermal resistance among all the combinations reduced, the thermal absorptivity of the combination textiles was lower than that of the innerwear alone, the thermal diffusion increased and the peak heat flow diminished for all the combinations. Practical implications: In practice, this comprehensive thermal comfort analysis provides specific combinations of inner and outer articles of clothing that are most appropriate for enhancing comfort during the summer season. Originality/value: Though there are many studies on the effect of multilayer fabrics on thermal properties, no extensive research analyses the influence of innerwear and outerwear combinations on thermal comfort properties. [ABSTRACT FROM AUTHOR]

Published
2024
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2. A new winding homogenization method based on thermal resistance concept.

Author

Hashemi, Ali, Yazdanpanah Qaraei, Parsa, and Shabanian-Poodeh, Mostafa

Subjects
*THERMAL resistance, *THERMAL batteries, *THERMAL properties, *THERMAL conductivity, *THERMAL analysis
Abstract

Purpose: The aim of this paper is to provide a simple yet accurate and efficient geometric method for thermal homogenization of impregnated and non-impregnated coil winding technologies based on the concept of thermal resistance. Design/methodology/approach: For regular windings, the periodic microscopic cell in the winding space is identified. Also, for irregular windings, the average microscopic cell of the winding is determined. An approximation is used to calculate the thermal resistance of the winding cell. Based on this approximation, the winding insulation is considered as a circular ring around the wire. Mathematical equations are obtained to calculate the equivalent thermal resistance of the cell. The equivalent thermal conductivity of the winding is calculated using equivalent thermal resistance of the cell. Winding thermal homogenization is completed by determining the equivalent thermal properties of the cell. Findings: The thermal pattern of different windings is simulated and compared with the results of different homogenization methods. The results show that the proposed method is applicable for a wide range of windings in terms of winding scheme, packing factor and winding insulation. Also, the results show that the proposed method is more accurate than other winding homogenization methods in calculating the equivalent thermal conductivity of the winding. Research limitations/implications: In this paper, the change of electrical resistance of the winding with temperature and thermal contact between the sub-components are ignored. Also, liquid insulators, such as oils, and rectangular wires were not investigated. Research in these topics is considered as future work. Originality/value: Unlike other homogenization methods, the proposed method can be applied to non-impregnated and irregular windings. Also, compared to other homogenization methods, the proposed method has a simpler formulation that makes it easier to program and implement. All of these indicate the efficiency of the proposed method in the thermal analysis of the winding. [ABSTRACT FROM AUTHOR]

Published
2024
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