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Article
Publication date: 1 February 2002

J.E. Ruckman, S.G. Hayes and J.H. Cho

Based upon numerous assertions that a garment should be developed to maximise athletes' muscle performance while maintaining freedom of movement, this paper initially…

Abstract

Based upon numerous assertions that a garment should be developed to maximise athletes' muscle performance while maintaining freedom of movement, this paper initially discusses the development of a perfusion suit that utilises a flexible single layer cooling system, with a view to the development of a cooling garment that does not employ a conventional tubing system which can restrict movement. The stages of the development have been described in detail, and an appropriate evaluation completed for both the initially developed perfusion suit and the subsequently developed cooling garment (modified perfusion suit). From results obtained from experiments conducted using the cooling garment, which incorporates super absorbent sodium polyacrylate pads as the cooling component, the following conclusions were drawn. First, anterior thigh temperature was reduced by 4–5°C at the end of the cooling period confirming that the developed cooling garment provides effective cooling. Second, although the difference between the skin temperature of the anterior thigh when cooling is applied to that when cooling is not applied decreased during the exercise period, the difference is still significant confirming that cooling of the anterior thigh by wearing the developed cooling garment persists throughout the duration of exercise.

Details

International Journal of Clothing Science and Technology, vol. 14 no. 1
Type: Research Article
ISSN: 0955-6222

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Article
Publication date: 3 October 2008

Kai Yang, Ming‐Li Jiao, Yi‐Song Chen, Jun Li and Wei‐Yuan Zhang

The purpose of this paper is to explore the heat transfer and establish a heat transfer model of an extravehicular liquid cooling garment based on a thermal manikin…

Abstract

Purpose

The purpose of this paper is to explore the heat transfer and establish a heat transfer model of an extravehicular liquid cooling garment based on a thermal manikin covered with soft simulated skin.

Design/methodology/approach

The thermal manikin applied in this study was a copper manikin, typical of which was its soft simulated skin – a newly thermoplastic elastomer material. Based on this novel thermal manikin, the heat transfer analysis of an extravehicular liquid cooling garment was performed. To satisfy the practical engineering application and simplify analysis, the hypotheses were proposed, and then the heat transfer model was established by heat transfer theory, in which the heat exchange equation of the liquid cooling garment with the thermal manikin and with the air layer, and the garment's total heat dissipating capacity were derived.

Findings

The verification experiments performed in a climatic chamber by a thermal manikin wearing a liquid cooling garment at different surface temperatures of the thermal manikin show that the modeling value fits well with the experimental value, and the heat transfer model of the liquid cooling garment has a high accuracy. Meanwhile, the relationship between the heat‐dissipating capacity of the liquid cooling garment and its design parameters – inlet temperature and liquid velocity – is suggested as being based on the heat transfer model.

Originality/value

The paper shows that it is an effective method to control the heat‐dissipating capacity of a liquid cooling garment by changing the inlet temperature to some degree, but not by changing the liquid velocity.

Details

International Journal of Clothing Science and Technology, vol. 20 no. 5
Type: Research Article
ISSN: 0955-6222

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Article
Publication date: 7 June 2013

Khurram Altaf, Ahmad Majdi Abdul Rani and Vijay R. Raghavan

The purpose of this paper is to present a technique of fabricating profiled conformal cooling channels (PCCC) in an aluminium filled epoxy mould using rapid prototyping…

Abstract

Purpose

The purpose of this paper is to present a technique of fabricating profiled conformal cooling channels (PCCC) in an aluminium filled epoxy mould using rapid prototyping (RP) and rapid tooling (RT) techniques and to compare the cooling times for the moulds with circular and profiled channels experimentally. The cooling channels in injection mould tools have a circular cross section. In a PCCC, the cross sectional shape is so designed that the flat face surface of the channel facing the cavity follows the profile of the cavity. These types of channels can be manufactured through RP and RT techniques.

Design/methodology/approach

A part to be moulded was designed and modelled. Two moulds were then designed with the part cavity, one having a circular channel and the second with a profiled channel, both having the same cross sectional area for coolant flow. The channel patterns were designed with supports according to their position regarding height and distance from the cavity as designed earlier. Both channels have the same distance from the cavity wall. RP patterns were produced for both channels and part using the Thermojet 3D printer. The cooling channel and the moulded part patterns were then assembled as designed in the moulds. Moulding frames were fabricated with aluminium plates and the pattern was placed in the frames. Epoxy was poured on the pattern and then cured. The moulded part and the channel patterns embedded inside epoxy were melted out during the final curing cycle, leaving behind the circular‐ and profiled‐cooling channels in the moulds. For the cooling time measurement, injection moulding was done with moulds with circular and profiled channels. Moulded part temperature will be recorded by embedding thermocouples within the mould cavities.

Findings

A technique for the manufacture of cooling channels of different profiles in epoxy moulds was presented. Experimental analysis for temperature measurement for the moulded part with injection moulding process showed that PCCC mould has less cooling time then mould with circular channels.

Research limitations/implications

The technique presented is based on the metal‐filled epoxy materials used in RT and was obtained using a specific test part. Epoxy tooling can be a useful alternative of metallic mould to produce injection mould tools. A limitation for the epoxy moulds is that they have a limited life as compared with metallic moulds.

Originality/value

This is a new technique of manufacturing moulds with cooling channels using RP/RT techniques. Moulds with different channel cross sections can be manufactured using this technique.

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Article
Publication date: 17 May 2011

Sheng‐hong Chen, Peifang Su and Isam Shahrour

Pipe cooling is an important measure for controlling the temperature in mass concrete. Since the temperature field in mass concrete containing cooling pipes is unsteady…

Abstract

Purpose

Pipe cooling is an important measure for controlling the temperature in mass concrete. Since the temperature field in mass concrete containing cooling pipes is unsteady and three‐dimensional, and there are huge quantities of the cooling pipes in the concrete, the study of efficient and reliable algorithm is crucial. The purpose of this paper is to develop the composite element method (CEM) for the temperature field in mass concrete containing cooling pipes.

Design/methodology/approach

Each cooling pipe segment is looked at as a special sub‐element having definite thermal characteristics, which is located explicitly within the composite element. By the variational principle, the governing equation for the composite element containing cooling pipes is established.

Findings

One of the remarkable advantages of the method proposed is that each cooling pipe can be simulated explicitly while the difficulty of mesh generation around cooling pipes can be avoided.

Originality/value

The paper demonstrates how composite elements containing cooling pipes are degenerated to the conventional finite elements automatically when the first stage artificial cooling finished, and conversely, the conventional finite elements can also be transformed to the composite elements automatically when the second stage artificial cooling started. The comparison of the numerical example using FEM and CEM shows the rationality of the proposed method.

Details

International Journal of Numerical Methods for Heat & Fluid Flow, vol. 21 no. 4
Type: Research Article
ISSN: 0961-5539

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Article
Publication date: 13 February 2017

Muhammad Usman, Qazi Shehzad Ali and Muhammed Bilal

Decreasing sources of fossil fuels has caused an increase in importance of the renewable energy resources and systems that directly utilize renewable energy are even more…

Abstract

Purpose

Decreasing sources of fossil fuels has caused an increase in importance of the renewable energy resources and systems that directly utilize renewable energy are even more important. The purpose of the paper is to compare the most common solar cooling technologies against the most important requirements.

Design/methodology/approach

A multi-criteria decision methodology, analytical hierarchical process, has been used to prioritize these technologies with respect to each other.

Findings

The findings of this study are the priorities of selected solar cooling concepts against performance affecting criteria. The solar vapour adsorption cooling system has been found to be the optimum solar cooling concept with practically the highest performance number compared with the other cooling systems.

Originality/value

This study can be used in the future development of solar cooling technologies to benefit from the best collective features of the specific technologies.

Details

World Journal of Engineering, vol. 14 no. 1
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 7 August 2017

Tao Yan, Liang Ma, Shuo Zhao and Enlin Yu

This study aims to focus on numerical simulation investigations of phase transformation during cooling of 55SiMnMo steel, which is commonly applied to improve mechanical…

Abstract

Purpose

This study aims to focus on numerical simulation investigations of phase transformation during cooling of 55SiMnMo steel, which is commonly applied to improve mechanical properties.

Design/methodology/approach

A mathematical model based on the finite element method (FEM) and the phase transformation kinetics model has been proposed to predict microstructure changes during continuous cooling of 55SiMnMo steel. This model can be employed to analyze the variation of austenite, special upper bainite and lump-like composite structure with cooling time at different cooling rates.

Finding

According to the continuous cooling experiments, when the cooling rate is lower than 0.1°C/s, the special upper bainite is the only transformation product which decreases with increasing cooling rate; when the cooling rate is above 0.5°C/s, the transformation products include special upper bainite and lump-like composite structure. Meanwhile, the results of continuous cooling experiment verified the correctness of this finite element model.

Originality/value

This model has a great value for proper controlling of the cooling process which can improve the quality of hollow drill steel and increase the service life of the final product.

Details

World Journal of Engineering, vol. 14 no. 4
Type: Research Article
ISSN: 1708-5284

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Article
Publication date: 5 September 2018

Byung-Hyun Shin, Junghyun Park, Jongbae Jeon, Sung-bo Heo and Wonsub Chung

In this study, super duplex stainless steel (SDSS) was heat-treated. The purpose of this study is to assess the effect of the cooling rate after heat treatment on the…

Abstract

Purpose

In this study, super duplex stainless steel (SDSS) was heat-treated. The purpose of this study is to assess the effect of the cooling rate after heat treatment on the pitting corrosion of SDSS.

Design/methodology/approach

The heat treatment from 1,000°C to 1,300°C was applied to SDSS to check the effect of the cooling rate.

Findings

The heat treatment temperature produced a different SDSS microstructure, and the cooling rate led to the growth of austenite. The casted SDSS indicated the presence of heterogeneous austenite, and the precipitation secondary phase under 1.6 per cent precipitated to bare metal. By applying heat treatment and cooling SDSS, its corrosion resistance changes because of the change in the chemical composition. The cooling rate at 5,600 J/s has the highest critical pitting temperature (CPT) at 1,100°C, and the cooling rate at 1.6 J/s has the highest CPT at 1,200°C. Low cooling rate (0.4 J/s) made the secondary phase at all temperature range.

Research limitations/implications

The effect of secondary phase not consider because that is well known to decreasing corrosion resistance.

Practical implications

Solution annealing is taken into account to optimize the corrosion resistance. But that is not consider the cooling rate at each temperature. This study assessed the effect of the cooling rate at each temperature point.

Social implications

Manufacturers need to know the effect of the cooling rate to optimize the corrosion resistance, and this study can be applied in the industrial scene.

Originality/value

SDSS is hard the optimization because SDSS is a dual-phase stainless steel. Corrosion resistance can be optimized by controlling heat treatment temperature and the cooling rate. Anyone not studied the effect of the cooling rate at each temperature. The effect of the cooling rate should be considered to optimize the corrosion resistance.

Details

Anti-Corrosion Methods and Materials, vol. 65 no. 5
Type: Research Article
ISSN: 0003-5599

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Article
Publication date: 12 October 2018

Xiaopeng Li, Brecht Van Hooreweder, Wout Lauwers, Bavo Follon, Ann Witvrouw, Kurt Geebelen and Jean-Pierre Kruth

The cooling process of polymer components fabricated by selective laser sintering (SLS) plays a vital role in determining the crystallinity, density and the resultant…

Abstract

Purpose

The cooling process of polymer components fabricated by selective laser sintering (SLS) plays a vital role in determining the crystallinity, density and the resultant properties of the produced parts. However, the control and optimization of the cooling process remains challenging. The purpose of this paper is to therefore investigate the cooling process of the SLS fabricated polyamide 12 (PA12) components through simulations. This work provides necessary fundamental insights into the possibilities for optimization and control of this cooling process for achieving desired properties.

Design/methodology/approach

The thermal properties of the PA12 powder and SLS fabricated PA12 components including density, specific heat and thermal conductivity were first determined experimentally. Then, the finite element method was used to optimize a container (a cuboid aluminum box where PA12 parts are built by the SLS) geometry in which the SLS parts can cool down in a controlled manner. Also, the cooling parameters required for maximum temperature homogeneity and minimum cooling time were determined.

Findings

Two different approximations in the finite element (FE) model were used and compared. It was found that the approximation which considers powder as a solid medium with porous material properties gives better results as compared to the approximation which treats powder as a collection of air and particles with solid material properties. The results also showed that the geometry of the containers has an important influence on the cooling process of the SLS fabricated PA12 components regarding temperature homogeneity and cooling time required. A container with a small width, long length and high height tends to result in a more homogenous temperature distribution during the cooling process.

Originality/value

Thermal constants of PA12 powder and parts were accurately determined as a starting point for numerical simulations. The FE model developed in this work provides useful and necessary information for the optimization and control of the cooling process of the SLS fabricated PA12 components and can thus be used for ensuring high-quality products with desired component properties.

Details

Rapid Prototyping Journal, vol. 24 no. 7
Type: Research Article
ISSN: 1355-2546

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Article
Publication date: 4 May 2010

Qinglong An, Yucan Fu and Jiuhua Xu

Grinding may generate high temperature along the arc of grinding zone, especially during the grinding process of difficult‐to‐machine materials. It can cause thermal…

Abstract

Purpose

Grinding may generate high temperature along the arc of grinding zone, especially during the grinding process of difficult‐to‐machine materials. It can cause thermal damage to the ground surface and poor surface integrity. Conventional cooling methods based on large amounts of water‐oil emulsions can be both ineffective and environmentally unacceptable. The purpose of this paper is to offer a new high efficiency cooling method – cryogenic pneumatic mist jet cooling (CPMJ) to enhance heat transfer in the grinding zone during grinding of difficult‐to‐machine materials.

Design/methodology/approach

CPMJ equipment is a set up, which can produce water mist of −5°C with jet velocity above 150 m/s and mean particle size below 20 μm at the impingement distance of 10‐40 mm on the symmetry axis. To validate the cooling efficiency of CPMJ equipment, heat transfer experiments were carrying out on it. Finally, CPMJ was applied to the grinding of titanium alloy to verify its cooling effects.

Findings

With high penetrative power and water mist of −5°C, CPMJ can greatly improve heat transfer efficiency in the grinding zone. Experimental results, including heat transfer experiments and grinding experiments, indicate that CPMJ has strong cooling ability and can offer better cooling effects compared with cold air jet and traditional flood cooling method. With CPMJ cooling method, grinding zone temperature can be effectively reduced and good surface quality can be achieved during grinding of titanium alloy.

Originality/value

CPMJ cooling method is an effective and pollution‐free way to solve the thermal problems during grinding of difficult‐to‐machine materials.

Details

Industrial Lubrication and Tribology, vol. 62 no. 3
Type: Research Article
ISSN: 0036-8792

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Article
Publication date: 1 December 1997

S. Chada, A. Herrmann, W. Laub, R. Fournelle, D. Shangguan and A. Achari

Detailed studies to characterise the coarsening behaviour of eutecticSn‐Ag and near‐eutectic Sn‐Pb‐Ag solder joints were carriedout on samples reflow soldered and…

Abstract

Detailed studies to characterise the coarsening behaviour of eutectic Sn‐Ag and near‐eutectic Sn‐Pb‐Ag solder joints were carried out on samples reflow soldered and solidified at various cooling rates. Light and scanning electron microscopy as well as EDS were used to study the microstructural evolution, while microhardness measurements were used to monitor the change in the mechanical properties. Samples consisting of copper substrates and solder paste were reflow soldered about 30 °C above their melting points and then solidified at cooling rates ranging from furnace cooling to rates associated with water quenching. Analysis of some of these samples showed that increasing the cooling rate increased the quantity (volume fraction) of primary Sn‐dendrites, decreased the (EQ) intermetallic phase in the bulk solder, and resulted in finer microstructures with higher hardness. The microstructural evaluation involved characterisation of bulk intermetallica and dendrite/eutectic ratios. Subsequent isothermal annealing of these reflow soldered joints at 125 °C for times between 0.25 h and 8 days resulted in an initially fairly rapid decrease in hardness to a given level for each alloy and each cooling rate.

Details

Soldering & Surface Mount Technology, vol. 9 no. 2
Type: Research Article
ISSN: 0954-0911

Keywords

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