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Article

Chaozhi Cai, Leyao Fan and Bingsheng Wu

This paper aims to understand the outlet temperature distribution of the combustor of a high-temperature, high-speed heat-airflow simulation system.

Abstract

Purpose

This paper aims to understand the outlet temperature distribution of the combustor of a high-temperature, high-speed heat-airflow simulation system.

Design/methodology/approach

The paper uses numerical simulation to study the temperature distribution of the combustor of a high-temperature, high-speed heat-airflow simulation system. First, the geometrical model of the combustor and the combustion model of the fuel are established. Then, the combustion of fuel in the combustor is simulated by using FLUENT under various conditions. Finally, the results are obtained.

Findings

The paper found three conclusions: when the actual fuel–gas ratio is equal to the theoretical fuel–gas ratio, the temperature in the combustor of the high-temperature, high-speed heat-airflow simulation system (HTSAS) can reach its highest and the distribution is the most uniform. Although increases in the total temperature of the inlet air can increase the highest temperature in the combustor of the HTSAS, the average temperature of the combustor outlet will decrease. At the same time, it will lead to an uneven temperature distribution of the combustor outlet. When the spray angle of the kerosene droplet is at 30 degrees, the outlet temperature field of the combustor is more uniform.

Originality/value

The paper presents a method to analyze the combustion performance of fuel and the gas temperature distribution in the combustor. The results will lay the foundation for the gas temperature control of a combustor.

Details

World Journal of Engineering, vol. 13 no. 5
Type: Research Article
ISSN: 1708-5284

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Article

Liang Du, Wei-Jun Zhang and Jian-Jun Yuan

This paper aims to present the design and experimental tests of an active circulating cooling system for the Experimental Advanced Superconducting Tokamak in-vessel…

Abstract

Purpose

This paper aims to present the design and experimental tests of an active circulating cooling system for the Experimental Advanced Superconducting Tokamak in-vessel inspection manipulator, which will help the current manipulator prototype to achieve a full-scale in-vessel high temperature environment compatibility.

Design/methodology/approach

The high-temperature effects and heat transfer conditions of the manipulator under in-vessel environment were analyzed. An active circulating cooling system was designed and implemented on the manipulator prototype. A simulative in-vessel inspection task in a high temperature environment of 100°C was carried out to evaluate the performance of the active circulating cooling system.

Findings

The proposed active circulating cooling system was proved effective in helping the manipulator prototype to achieve its basic in-vessel inspection capability in a high temperature environment. The active circulating cooling system performance can be further improved considering the cooling structure coefficient differences in different manipulator parts.

Originality/value

For the first time, the active circulating cooling system was implemented and tested on a full-scale of the in-vessel inspection manipulator. The experimental data of the temperature distribution inside the manipulator and the operating status of the circulating system were helpful to evaluate the current active circulating cooling system design and provided effective guidance for improving the overall system performance.

Details

Industrial Robot: the international journal of robotics research and application, vol. 47 no. 5
Type: Research Article
ISSN: 0143-991X

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Article

Vitus Mwinteribo Tabie, Chong Li, Wang Saifu, Jianwei Li and Xiaojing Xu

This paper aims to present a broad review of near-a titanium alloys for high-temperature applications.

Abstract

Purpose

This paper aims to present a broad review of near-a titanium alloys for high-temperature applications.

Design/methodology/approach

Following a brief introduction of titanium (Ti) alloys, this paper considers the near-α group of Ti alloys, which are the most popular high-temperature Ti alloys developed for a high-temperature application, particularly in compressor disc and blades in aero-engines. The paper is relied on literature within the past decade to discuss phase stability and microstructural effect of alloying elements, plastic deformation and reinforcements used in the development of these alloys.

Findings

The near-a Ti alloys show high potential for high-temperature applications, and many researchers have explored the incorporation of TiC, TiB SiC, Y2O3, La2O3 and Al2O3 reinforcements for improved mechanical properties. Rolling, extrusion, forging and some severe plastic deformation (SPD) techniques, as well as heat treatment methods, have also been explored extensively. There is, however, a paucity of information on SiC, Y2O3 and carbon nanotube reinforcements and their combinations for improved mechanical properties. Information on some SPD techniques such as cyclic extrusion compression, multiaxial compression/forging and repeated corrugation and straightening for this class of alloys is also limited.

Originality/value

This paper provides a topical, technical insight into developments in near-a Ti alloys using literature from within the past decade. It also outlines the future developments of this class of Ti alloys.

Details

Aircraft Engineering and Aerospace Technology, vol. 92 no. 4
Type: Research Article
ISSN: 1748-8842

Keywords

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Article

Kai Yang, Mingli Jiao, Sifan Wang, Yuanyuan Yu, Quan Diao and Jian Cao

The purpose of this paper is to investigate thermoregulation properties of different composite phase change materials (PCMs), which could be used in the high temperature

Abstract

Purpose

The purpose of this paper is to investigate thermoregulation properties of different composite phase change materials (PCMs), which could be used in the high temperature environmental conditions to protect human body against the extra heat flow.

Design/methodology/approach

Three kinds of composite PCM samples were prepared using the selected pure PCMs, including n-hexadecane, n-octadecane and n-eicosane. The DSC experiment was performed to get the samples’ phase change temperature range and enthalpy. The simulated high temperature experiments were performed using human arms in three different high temperature conditions (40°C, 45°C, 50°C), and the skin temperature variation curves varying with time were obtained. Then a comprehensive index TGP was introduced from the curves and calculated to evaluate the thermoregulation properties of different composite PCM samples comprehensively.

Findings

Results show that the composite PCM samples could provide much help to the high temperature human body. It could decrease the skin temperature quickly in a short time and it will not cause the over-cooling phenomenon. Comparing with other two composite PCM samples, the thermoregulation properties of the n-hexadecane and n-eicosane composite PCM is the best.

Originality/value

Using the n-hexadecane and n-eicosane composite PCM may provide people with better protection against the high temperature conditions, which is significative for the manufacture of functional thermoregulating textiles, garments or equipments.

Details

International Journal of Clothing Science and Technology, vol. 30 no. 4
Type: Research Article
ISSN: 0955-6222

Keywords

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Article

F.P. McCluskey, L. Condra, T. Torri and J. Fink

An overview of the concerns involved in the operation of electronic hardware at elevated temperaturesis presented. Materials selection and package design issues are…

Abstract

An overview of the concerns involved in the operation of electronic hardware at elevated temperatures is presented. Materials selection and package design issues are addressed for a wide range of packaging elements from the semiconductor chip to the box. It is found that most elements of common high density device and packaging architecture can be used up to 200°C. However, gold‐aluminium wirebonds, eutectic tin‐lead solder joints and die attaches, and FR‐4 boards will seriously degrade at temperatures below 200°C. For these elements, alternative materials of construction are recommended. Comparisons are made between package design for high power dissipation and that for high temperature operation.

Details

Microelectronics International, vol. 13 no. 3
Type: Research Article
ISSN: 1356-5362

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Article

Anindya Ghoshal, Dy Le and HeungSoo Kim

Presently there exists no way to directly measure strain at high temperatures in engine components such as the combustion chamber, exhaust nozzle, propellant lines, and…

Abstract

Purpose

Presently there exists no way to directly measure strain at high temperatures in engine components such as the combustion chamber, exhaust nozzle, propellant lines, and turbine blades and shaft. The purpose of this paper is to address this issue.

Design/methodology/approach

Thermomechanical fatigue (TMF) prediction, which is a critical element for a blade design, is a strong function of the temperature and strain profiles. Major uncertainties arise from the inability of current instrumentation to measure temperature and strain at critical locations. This prevents the structural designer from optimizing the blade design for high temperature environments, which is a significantly challenging problem in engine design.

Findings

Being able to directly measure strains in different high temperature zones would deeply enhance the effectiveness of aircraft propulsion systems for fatigue damage assessment and life prediction. The state of the art for harsh environment, high temperature sensors has improved considerably over the past few years.

Originality/value

This paper lays down specifications for high temperature sensors and provides a technological assessment of these new sensing technologies. The paper also reviews recent advances made in harsh environment sensing systems and takes a peek at the future of such technologies.

Details

Sensor Review, vol. 32 no. 1
Type: Research Article
ISSN: 0260-2288

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Article

Bernd‐Robert Höhn, Klaus Michaelis and Hans‐Philipp Otto

The purpose of this paper is to make an attempt to evaluate the pitting load carrying capacity under increased thermal conditions. This is the basis for an estimated…

Abstract

Purpose

The purpose of this paper is to make an attempt to evaluate the pitting load carrying capacity under increased thermal conditions. This is the basis for an estimated lifetime which is one of the most important parameters defining transmission reliability.

Design/methodology/approach

Recommendations related to pitting load carrying capacity calculation of case hardened gears running at high gear bulk temperatures are formulated. These factors are based on extensive experimental data, obtained in pitting tests with high oil injection temperatures, high oil sump temperatures or high operational gear bulk temperatures due to a lack of heat dissipation caused by minimised lubrication.

Findings

Testing of gear type C‐PT on FZG back‐to‐back test rig at high gear bulk temperatures by either heating up the lubricant or caused by a lack of heat dissipation as it appears with poor lubrication conditions resulted in a decrease of up to 30 per cent of the endurance strength in various investigations. This results in a reduction of the material strength due to tempering effects and high surface shear stress due to low oil film thicknesses caused by low operating oil viscosities.

Originality/value

The present calculation method in the standard DIN/ISO is not valid for high gear bulk temperatures. Nevertheless, the present calculation algorithms of the standards DIN/ISO are valid for low and moderate thermal operating conditions when using oil temperatures of up to 80 (90)°C in the case of a sufficient cooling oil supply to the gear mesh. With the presented modifications higher gear bulk temperatures (>120°C) can be taken into account.

Details

Industrial Lubrication and Tribology, vol. 63 no. 1
Type: Research Article
ISSN: 0036-8792

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Article

Pengju Li, Yongsheng Zhu, Youyun Zhang and Pengfei Yue

– This paper aims to present the theoretical and experimental investigation of the temperature of high speed and heavy haul tilting pad journal bearing.

Abstract

Purpose

This paper aims to present the theoretical and experimental investigation of the temperature of high speed and heavy haul tilting pad journal bearing.

Design/methodology/approach

The bearing is 152.15 mm in diameter with three slenderness ratios (L/D) and three clearance ratios. The equations that govern the flow and energy transport are solved by the finite difference method, and the experimental tests are conducted in a test rig of high speed and heavy haul tilting pad journal bearing. The shaft speed ranges from 3,000 to 16,500 r/min (the highest linear-velocity equals 131.4 m/s), and the three static loads are 10, 20 and 30 KN.

Findings

The comparisons between numerical results and experimental results show better correlations. It is shown in the theoretical and experimental results that the temperature increases with static load and shaft speed and decreases with clearance ratio and L/D.

Originality/value

The theoretical models presented in this paper can be used to predict the temperature of tilting pad journal bearing when the shaft’s linear velocity is up to 130 m/s.

Details

Industrial Lubrication and Tribology, vol. 67 no. 4
Type: Research Article
ISSN: 0036-8792

Keywords

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Article

Qijing Lin, Zirong Wu, Na Zhao, Zhuangde Jiang, Qidong Zhang, Bian Tian and Peng Shi

The Fabry-Perot sapphire optical fiber sensor is an excellent choice for high-temperature sensing in civil and military fields, such as oil exploitation, engine and…

Abstract

Purpose

The Fabry-Perot sapphire optical fiber sensor is an excellent choice for high-temperature sensing in civil and military fields, such as oil exploitation, engine and turbine. The purpose of this paper is to study the high-reflective film system withstanding high temperature in Fabry-Perot sapphire optical fiber high-temperature sensor. To improve the performance of the sensor and reduce the difficulty of signal acquisition, one of the key ways is to enhance the normalized light intensity of F-P sensor, which can be achieved by coating the high-reflective film system on the fiber end.

Design/methodology/approach

The high-reflective film system can be achieved by a multilayer film with alternating ZrO2 and Al2O3 film layers whose refractive indexes are different. In addition, the optimum film alternating sequences and the influence of the number of film layers, incident angle and temperature should be obtained by numerical analysis.

Findings

With the increase of the number of film layers, the reflectivity rises gradually and the change trend is more and more gentle. A minimum of the spectral reflectivity will occur at a certain incident angle depending on the design of the periodic multilayer system. Temperature affects the reflectivity of high-reflective film system. The normalized light intensity of the F-P sensor coated with high-reflective film system enhances greatly which is helpful to the signal demodulation. The temperature response of the F-P sensor is mainly determined by the characteristics of the F-P cavity.

Originality/value

Higher reflectivity, lower cost and easy signal acquisition are the most important features of the introduced high-reflective film system for the Fabry-Perot sapphire optical fiber high-temperature sensor.

Details

Sensor Review, vol. 39 no. 2
Type: Research Article
ISSN: 0260-2288

Keywords

Content available
Article

Chunlan Li, Jun Wang, Min Liu, Desalegn Yayeh Ayal, Qian Gong, Richa Hu, Shan Yin and Yuhai Bao

Extreme high temperatures are a significant feature of global climate change and have become more frequent and intense in recent years. These pose a significant threat to…

Abstract

Purpose

Extreme high temperatures are a significant feature of global climate change and have become more frequent and intense in recent years. These pose a significant threat to both human health and economic activity, and thus are receiving increasing research attention. Understanding the hazards posed by extreme high temperatures are important for selecting intervention measures targeted at reducing socioeconomic and environmental damage.

Design/methodology/approach

In this study, detrended fluctuation analysis is used to identify extreme high-temperature events, based on homogenized daily minimum and maximum temperatures from nine meteorological stations in a major grassland region, Hulunbuir, China, over the past 56 years.

Findings

Compared with the commonly used functions, Weibull distribution has been selected to simulate extreme high-temperature scenarios. It has been found that there was an increasing trend of extreme high temperature, and in addition, the probability of its indices increased significantly, with regional differences. The extreme high temperatures in four return periods exhibited an extreme low hazard in the central region of Hulunbuir, and increased from the center to the periphery. With the increased length of the return period, the area of high hazard and extreme high hazard increased. Topography and anomalous atmospheric circulation patterns may be the main factors influencing the occurrence of extreme high temperatures.

Originality/value

These results may contribute to a better insight in the hazard of extreme high temperatures, and facilitate the development of appropriate adaptation and mitigation strategies to cope with the adverse effects.

Details

International Journal of Climate Change Strategies and Management, vol. 11 no. 1
Type: Research Article
ISSN: 1756-8692

Keywords

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