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Article
Publication date: 26 August 2014

Ming Fu, Wenguo Weng and Hongyong Yuan

– The purpose of this paper is to measure the thermal insulation of protective clothing with multilayer gaps in low-level heat exposures.

Abstract

Purpose

The purpose of this paper is to measure the thermal insulation of protective clothing with multilayer gaps in low-level heat exposures.

Design/methodology/approach

Nine different combinations of protective clothing systems with multiple air gaps are used to measure the thermal insulation by a self-designed bench-scale test apparatus in different levels of an external thermal radiation of 2-10 kW/m2. The outside and inside surface temperatures of each fabric layer are also measured to calculate the local thermal insulation of each fabric layer and each air gap.

Findings

The results show that the total thermal insulation of protective clothing under thermal radiation is less than that in normal environments, and the exposed thermal radiation will worsen the total thermal insulation of the multilayer fabric systems. Air gap plays a positive role in the total thermal insulation, and thus provides the enhanced thermal protection. It is also suggested that the local resistance of the air gap closer to the external thermal radiation is more easily affected by the thermal radiation, due to the different heat transfer ways in the fabric system and the external thermal radiation.

Originality/value

Effects of air gap on the thermal insulation of protective clothing, and contribution of the local thermal resistance of each fabric layer and each air gap to the total thermal insulation.

Details

International Journal of Clothing Science and Technology, vol. 26 no. 5
Type: Research Article
ISSN: 0955-6222

Keywords

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Article
Publication date: 1 August 2011

Jinjing Chen and Weidong Yu

In this paper, a method of designing flexible multilayer insulation is analyzed and discussed, with focus on reducing the three basic modes of heat transfer (thermal

Abstract

In this paper, a method of designing flexible multilayer insulation is analyzed and discussed, with focus on reducing the three basic modes of heat transfer (thermal radiation, solid spacer and residual gas conduction). The foundation for designing the new flexible thermal insulation material is provided. The insulation performances of different types (by choosing different reflection shields and spacers) of flexible multilayer insulation materials are obtained through measurements using a KES-F7 Thermal Labo II apparatus. The thermal performance of flexible multilayer insulation materials at different layers are also presented, and the best is about 20∼25 layers. To improve the thermal performance of multilayer insulation materials, treble spacers between double aluminized shields are applied. Aluminized shields with air, meshes, wool fibres, etc. are compared with each other. The aluminized shields with meshes fixed with down can reduce thermal contact, which reduces the radiation heat transfer more fully and can be more steady than the other spacers in the project applications. With the same layers and spacers, the thermal conductivity of crinkled aluminized shields is lower than that of the smooth aluminized shields. The effects of compressive loads on layer density and thermal performance are also investigated.

Details

Research Journal of Textile and Apparel, vol. 15 no. 3
Type: Research Article
ISSN: 1560-6074

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Article
Publication date: 15 July 2020

Fatemeh Zahra Hourian Tabarestani, Fatemeh Mousazadegan and Nazanin Ezazshahabi

In the present work, the thermal insulation characteristics of multilayered mittens were studied in different airflow conditions.

Abstract

Purpose

In the present work, the thermal insulation characteristics of multilayered mittens were studied in different airflow conditions.

Design/methodology/approach

In this study, the thermal behavior of four groups of mittens consisting of one two-layer and three three-layer mittens containing nonwoven wadding materials with various weights and thicknesses was investigated during the exposure to airflows with different speeds. In order to evaluate the correlation between the heat transfer rates of different mittens with the human perception of cold, a set of pair-comparison tests was performed using Thurstone's law of comparative judgment.

Findings

The analysis of the results revealed that by an increment in the weight and the thickness of the wadding material, the thermal protection performance of mittens improves. Moreover, in the presence of airflow and by increasing its speed, due to the forced convective heat loss, the outer surface temperature of the mittens decreases and therefore the conductive heat transfer rate rises. This fact leads to the transfer of higher quantity of body warmth to the environment and thus feeling of coldness. According to the results, there was a proper correlation between the subjective perception of cold and the heat transfer rate of mittens. The statistical analysis of the results clarified that the effect of mitten's structural parameters and the airflow speed on the thermal protection behavior of mittens are significant at the confidence range of 95%.

Originality/value

Mitten is one of the important personal protective clothing, especially in cold environments. Thus, the thermal resistance of them has a prominent role in the protection of the hands and fingers from cold and frostbiting.

Details

International Journal of Clothing Science and Technology, vol. 33 no. 2
Type: Research Article
ISSN: 0955-6222

Keywords

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Article
Publication date: 1 August 2016

Shurong Hu, Mengmeng Zhao and Jun Li

– The purpose of this paper is to explore the effects of wind direction and ease allowance on thermal comfort in sportswear.

Abstract

Purpose

The purpose of this paper is to explore the effects of wind direction and ease allowance on thermal comfort in sportswear.

Design/methodology/approach

The effects of wind direction (front, side, back and calm (no wind) 1.5 m/s) and seven magnitudes of ease allowance on sportswear thermal insulation and surface temperature were investigated. An 11 zones’ thermal manikin was used to acquire the static thermal insulation. Surface temperature was captured by a thermal imager.

Findings

The results showed that the wind was a significant effect on thermal performance, however, wind direction effect was only significant in the segment covered with multilayer fabric, such as the abdomen and hip (p=0.034). Although the ease allowance influenced the overall thermal insulation obviously, the difference between seven sizes suits was not significant. Nevertheless, the ease allowance affected the surface temperature of chest and back significantly (p=0.023, 0.007). Correlation between thermal insulation and surface temperature was negative, and correlation level was degraded when affected by wind factor.

Research limitations/implications

Sportswear’s fabric and style did not discussed as effect factors. It would be taken into accounted in the future research.

Originality/value

Wind direction impact thermal comfort in multilayer regions significantly. It is a reference to improve sportswear’s comfort design.

Details

International Journal of Clothing Science and Technology, vol. 28 no. 4
Type: Research Article
ISSN: 0955-6222

Keywords

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Article
Publication date: 6 March 2017

Aleksey V. Nenarokomov, Leonid A. Dombrovsky, Irina V. Krainova, Oleg M. Alifanov and Sergey A. Budnik

The purpose of this study is to optimize multilayer vacuum thermal insulation (MLI) of modern high-weight spacecrafts. An adequate mathematical simulation of heat transfer…

Abstract

Purpose

The purpose of this study is to optimize multilayer vacuum thermal insulation (MLI) of modern high-weight spacecrafts. An adequate mathematical simulation of heat transfer in the MLI is impossible if there is no available information on the main insulation properties.

Design/methodology/approach

The results of experiments in thermo-vacuum facilities are used to re-estimate some radiative properties of metallic foil/metalized polymer foil and spacer on the basis of the inverse problem solution. The experiments were carried out for the sample of real MLI used for the BP-Colombo satellite (ESA). The recently developed theoretical model based on neglecting possible near-field effects in radiative heat transfer between closely spaced aluminum foils was used in theoretical predictions of heat transfer through the MLI.

Findings

A comparison of the computational results and the experimental data confirms that there are no significant near-field effects between the neighboring MLI layers. It means that there is no considerable contradiction between the far-field model of radiative transfer in MLI and the experimental estimates.

Originality/value

An identification procedure for mathematical model of the multilayer thermal insulation showed that a modified theoretical model developed recently can be used to estimate thermal properties of the insulation at conditions of space vacuum.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 3
Type: Research Article
ISSN: 0961-5539

Keywords

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Article
Publication date: 2 May 2017

Aleksey V. Nenarokomov, Margarita O. Salosina and Oleg M. Alifanov

The presented paper aims to consider algorithm for optimal design of multilayer thermal insulation.

Abstract

Purpose

The presented paper aims to consider algorithm for optimal design of multilayer thermal insulation.

Design/methodology/approach

Developed algorithm is based on a sequential quadratic programming method.

Findings

2D mathematical model of heat transfer in thermal protection was considered in frame of thermal design of spacecraft. The sensitivity functions were used to estimate the Jacobean of the object functions.

Research limitations/implications

Design of distributed parameter systems and shape optimization may be thought of as geometrical inverse problems, in which the positions of free boundaries are determined along with the spatial variables. In such problems, the missing data (i.e. the position of boundaries) are compensated for by the presence of the so-called inverse problem additional conditions. In the case under consideration, such conditions are constrains on the temperature values at the discrete points of the system.

Practical implications

Results are presented how to apply the algorithm suggested for solving a practical problem – thickness sampling for a thermal protection system of advanced solar probe.

Originality/value

The procedure proposed in the paper to solve a design problem is based on the method of quadratic approximation of the initial problem statement as a Lagrange formulation. This has allowed to construct a rather universal algorithm applicable without modification for solving a wide range of thermal design problems.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 27 no. 5
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 2 November 2015

Ming Fu, Wenguo Weng and Hongyong Yuan

– The purpose of this paper is to study the combined effects of moisture and radiation on thermal protective performance of protective clothing exposed to low level radiation.

Abstract

Purpose

The purpose of this paper is to study the combined effects of moisture and radiation on thermal protective performance of protective clothing exposed to low level radiation.

Design/methodology/approach

Using a sweating manikin, the effect of radiation and moisture on heat and moisture transfer was initially analyzed under the dry manikin with sweating rate of 100 g/(m2h) exposed to 2.5 kW/m2, and then studied at 200 and 300 g/(m2h) exposed to 2 and 3 kW/m2, respectively. Finally, the combined effects of thermal radiation and moisture were predicted by fitting the relationships among heat loss and wet skin surface temperature, with the sweating rate and radiation intensity.

Findings

The results show that the heat loss and the wet skin surface temperature are affected by the combined effects of moisture and radiation, with two distinctly different trends. Heat loss from the manikin is increasing with the sweating rate, and decreasing with thermal radiation intensity. However, the wet skin surface temperature has an opposite situation.

Originality/value

Two filling equations are given to present the relationships among heat loss and wet skin surface temperature, with the sweating rate and radiation intensity. With these two equations, the heat loss and the wet skin surface temperature when exposed to radiation can be predicted by only measuring the mean radiant and ambient temperatures and controlling the sweating rate.

Details

International Journal of Clothing Science and Technology, vol. 27 no. 6
Type: Research Article
ISSN: 0955-6222

Keywords

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Article
Publication date: 29 May 2020

Jingxian Xu, Huijuan Liu, Yunyi Wang and Jun Li

This study aims to investigate the heat transfer mechanism of the uniforms used by people working in hot, humid and windy environments. Furthermore, the effectiveness of…

Abstract

Purpose

This study aims to investigate the heat transfer mechanism of the uniforms used by people working in hot, humid and windy environments. Furthermore, the effectiveness of an opening structure added to the armpit of the uniforms in improving thermal comfort was comparatively examined.

Design/methodology/approach

A set of uniforms was tested with the opening at the armpit alternatively zipped or unzipped. Thermal manikin and human tests were performed in a climatic chamber simulating the specific environmental conditions, including wind speeds at four levels (0.15, 0.5, 2, 4 m/s) and relative humidities at two levels (50 and 85%). Static and dynamic thermal insulations of clothing (IT) were examined by the thermal manikin tests. The human bodies' thermal responses, including heart rates (HR), eardrum temperatures (Te), skin temperatures (Tsk) and subjective perceptions, were given by the human tests.

Findings

Special mechanisms of heat transfer in the specific uniforms used in tropical monsoon climates were revealed. Reductions on IT were caused by the movement of the human body and the environmental wind, and the empirical equations would underestimate this reduction. The opening at the armpit was able to prompt more heat transfer under dynamic condition, with reducing the IT by 11.8%, lowering the mean Tsk by 0.92°C, and significantly improving the subjective perceptions (p < 0.05). The heat exhaustion was alleviated with lowering the Te by 0.32°C.

Originality/value

This study managed to improve the thermal performance of uniforms for workers under unforgiving conditions. The evaluation and design methods introduced by this study provided practical guidance for similar products with strict dress codes and cost control requirements based on the findings from thorough product tests and analysis.

Details

International Journal of Clothing Science and Technology, vol. 32 no. 6
Type: Research Article
ISSN: 0955-6222

Keywords

Content available
Article
Publication date: 2 March 2015

Abstract

Details

International Journal of Clothing Science and Technology, vol. 27 no. 1
Type: Research Article
ISSN: 0955-6222

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Article
Publication date: 10 April 2017

Cristina Pusceddu, George Blumberg, Graziano Salvalai and Marco Imperadori

This paper aims to report on a study to investigate the feasibility of thermal reflective multi-layer system (TRMS) as support for disaster resilience.

Abstract

Purpose

This paper aims to report on a study to investigate the feasibility of thermal reflective multi-layer system (TRMS) as support for disaster resilience.

Design/methodology/approach

It is an innovative insulation system, developed from space engineering studies, is lightweight and is characterised by a thermal conductivity of 0.038 W/mK, making it a strong candidate for inexpensive shelter after disaster design.

Findings

One of the results of this study is a proposal for the air shelter house, a new concept design of a shelter based on TRMS.

Originality/value

The combined use of TRMS with the low cost of building materials and a 3D printer system for the construction joints provides a good compromise between building cost and energy efficiency performance. Such an innovative design supports disaster resilience during response, reconstruction and mitigation phases, and it is suitable for a wide variety of cultural and environmental situations where energy efficiency is important.

Details

International Journal of Disaster Resilience in the Built Environment, vol. 8 no. 02
Type: Research Article
ISSN: 1759-5908

Keywords

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