Search results
1 – 10 of over 12000Tan Chen, Wei-jun Zhang, Jian-jun Yuan, Liang Du and Ze-yu Zhou
This paper aims to present a different cooling method (water cooling) to protect all the mechanical/electrical components for Tokamak in-vessel inspection manipulator. The method…
Abstract
Purpose
This paper aims to present a different cooling method (water cooling) to protect all the mechanical/electrical components for Tokamak in-vessel inspection manipulator. The method is demonstrated effective through high temperature experiment, which provides an economical and robust approach for manipulators to work normally under high temperature.
Design/methodology/approach
The design of cooling system uses spiral copper tube structure, which is versatile for all types of key components of manipulator, including motors, encoders, drives and vision systems. Besides, temperature sensors are set at different positions of the manipulator to display temperature data to construct a close-loop feedback control system with cooling components.
Findings
The cooling system for the whole inspection manipulator working under high temperature is effective. Using insulation material such as rubber foam as component coating can significantly reduce the environmental heat transferred to cooling system.
Originality/value
Compared with nitrogen gas cooling applied in robotic protection design, although it is of less interest in prior research, water cooling method proves to be effective and economical through our high temperature experiment. This paper also presents an energetic analysis method to probe into the global process of water cooling and to evaluate the cooling system.
Details
Keywords
Omid Pourali, Hashem Ghasemi Kadijani and Farideh Mohammadi Khangheshlaghi
An effective chemical conditioning technique was successfully tested and investigated to control and minimize the chemistry-related damages within mixed metallurgy steam and water…
Abstract
Purpose
An effective chemical conditioning technique was successfully tested and investigated to control and minimize the chemistry-related damages within mixed metallurgy steam and water cycle of Heller dry cooled combined cycle power plants (CCPPs), in which cooling water and condensate are completely mixed in direct contact condenser. This study aims to perform a comprehensive experimental research in four mixed metallurgy steam and water cycle.
Design/methodology/approach
A comprehensive experimental study was carried out in four mixed metallurgy steam and water cycle fabricated with ferrous- and aluminum-based alloys which have various corrosion resistance capabilities in contact with water. Chemical conditioning was conducted using both volatile and non-volatile alkalizing agents, and, to perform chemical conditioning effectively, quality parameters (pH, conductivity, dissolved oxygen, sodium, silica, iron, aluminum and phosphate) were monitored by analyzing grab and online samples taken at eight key sampling points.
Findings
Results indicated that pH was the most critical parameter which was not mainly within the recommended ranges of widely used standards and guidelines at all key sampling points that generally increases the occurrence of chemistry-related damages. The other quality parameters were mostly satisfactory.
Originality/value
In this research, the development of a suitable chemical conditioning technique in mixed metallurgy steam and water cycle, fabricated with ferrous and aluminum-based alloys, was studied. The obtained results in this thorough research work was evaluated by comparison with the chemistry limits of the widely used standards and guidelines, and combined use of volatile and solid alkalizing agents was considered as a promising chemical conditioning technique for utilization in mixed metallurgy units of Heller dry cooled CCPPs.
Details
Keywords
Mehmet Akif Ceviz, Faraz Afshari, Burak Muratçobanoğlu, Murat Ceylan and Eyüphan Manay
The purpose of this paper is to experimentally and numerically investigate the cooling performance of the air-to-water thermoelectric cooling system under different working…
Abstract
Purpose
The purpose of this paper is to experimentally and numerically investigate the cooling performance of the air-to-water thermoelectric cooling system under different working conditions.
Design/methodology/approach
An air-to-water thermoelectric cooling system was designed and manufactured according to the principle of discrete binary thermoelectric Peltier modules, and the thermal performance, heat transfer rate and average COP values were examined at different cooling water temperatures and voltages applied. Additionally, numerical simulations were performed by computational fluid dynamics approach to investigate the temperature distribution and airflow structure inside the cooling chamber.
Findings
Analyses were performed using experimental tests and numerical methods. It was concluded that, by decreasing the cooling water temperature from 20 to 5 °C, the average COP increases about 36%. The voltage analysis showed that the efficiency of the system does not always increase as the voltage rises; more importantly, the optimum voltage is different and depends on whether it is desired to increase COP or increase the cooling rate.
Originality/value
In the studies published in the field of thermoelectric cooling systems, little attention has been paid to the voltage applied and its relationship to other operating conditions. In most cases, the tests are performed at a constant voltage. In this study, several options, including applied voltage and cooling water temperature, were considered simultaneously and their effects on performance have been tested. It was found that under such studies, optimization work should be done to evaluate maximum performance in different working conditions.
Details
Keywords
This article discusses the basics of computer‐room air conditioning, an important component of the special environment required by mainframe computers and many mini‐computers as…
Abstract
This article discusses the basics of computer‐room air conditioning, an important component of the special environment required by mainframe computers and many mini‐computers as well. Computer room air conditioners differ in some significant ways from “comfort” air‐conditioners, which are designed for the comfort of people rather than machines. These differences make it less than ideal to use air conditioning systems designed for human comfort for computer cooling. The author describes several different types of air‐conditioners, considerations related to the construction of a computer room, and factors that determine air‐conditioning requirements.
Eduardo Alencar de Souza and José Antônio da Cunha Ponciano Gomes
– The aim was to study the effect of an electromagnetic treatment used on corrosion control of carbon steel in cooling systems.
Abstract
Purpose
The aim was to study the effect of an electromagnetic treatment used on corrosion control of carbon steel in cooling systems.
Design/methodology/approach
The aim was to assess the performance of an electromagnetic treatment used on corrosion control of carbon steel in cooling water systems.
Findings
The main conclusion is that the electromagnetic system cannot induce a direct effect on the corrosion rates. The use of chemical corrosion inhibitors cannot be suggested.
Social implications
The optimized industrial use of water is an objective of unquestionable importance, as water is a finite resource. The use of efficient corrosion control on water cooling systems permits the reduction of the water volume required. Consequently, a social benefit can be associated with the improvement of corrosion control technologies.
Originality/value
The development of alternative corrosion control technologies, such as the use of physical treatments, has been considered as a promising tool. In this work, a consistent assessment of the results achieved on a full-scale system, without using chemical corrosion inhibitors, is presented.
Details
Keywords
Xie Xuejun, Yuanlin Zhang, Rui Wang, Yu Zhang and Mianzhao Ruan
The hollow copper wires of the generator are seriously corroded in cooling water. This paper aims to explore the mechanism of copper corrosion by thermodynamic calculation and…
Abstract
Purpose
The hollow copper wires of the generator are seriously corroded in cooling water. This paper aims to explore the mechanism of copper corrosion by thermodynamic calculation and kinetic experiments and to find out the precise pH range for preventing corrosion of copper in stator internal water and dual internal water cooled generators.
Design/methodology/approach
Thermodynamic and kinetic studies were carried out for the purpose of preventing the corrosion of hollow conducting copper wires in the internal cooling water. Thermodynamic calculation results demonstrate hollow copper wires electrochemically corroded by oxygen rather than acids (H+) and find out a precise anti-corrosion pH range. Kinetic experiments research on the effect of the pH value and oxygen concentration on corrosion and protection methods of copper in desalted water.
Findings
Research results demonstrate that, in the internal cooling water, hollow copper wires are electrochemically corroded by oxygen, rather than acids (H+). The method of preventing copper from corrosion in the desalted water is to control the pH value of the stator cooling water and the dual water inner cooling water between 7.86-8.86 and 7.86-9.26, respectively.
Originality/value
The thermodynamic calculation and potentiometric-pH diagram are used to obtain the accurate pH range of the inner cooling water and inner cooling water in the inner cooling water system. The kinetic experiments provide data support for the effect of temperature, pH value and oxygen concentration.
Details
Keywords
Nzita Alain Lelo, P. Stephan Heyns and Johann Wannenburg
Steam explosions are a major safety concern in many modern furnaces. The explosions are sometimes caused by water ingress into the furnace from leaks in its high-pressure (HP…
Abstract
Purpose
Steam explosions are a major safety concern in many modern furnaces. The explosions are sometimes caused by water ingress into the furnace from leaks in its high-pressure (HP) cooling water system, coming into contact with molten matte. To address such safety issues related to steam explosions, risk based inspection (RBI) is suggested in this paper. RBI is presently one of the best-practice methodologies to provide an inspection schedule and ensure the mechanical integrity of pressure vessels. The application of RBIs on furnace HP cooling systems in this work is performed by incorporating the proportional hazards model (PHM) with the RBI approach; the PHM uses real-time condition data to allow dynamic decision-making on inspection and maintenance planning.
Design/methodology/approach
To accomplish this, a case study is presented that applies an HP cooling system data with moisture and cumulated feed rate as covariates or condition indicators to compute the probability of failure and the consequence of failure (CoF), which is modelled based on the boiling liquid-expanding vapour explosion (BLEVE) theory.
Findings
The benefit of this approach is that the risk assessment introduces real-time condition data in addition to time-based failure information to allow improved dynamic decision-making for inspection and maintenance planning of the HP cooling system. The work presented here comprises the application of the newly proposed methodology in the context of pressure vessels, considering the important challenge of possible explosion accidents due to BLEVE as the CoF calculations.
Research limitations/implications
This paper however aims to optimise the inspection schedule on the HP cooling system, by incorporating PHM into the RBI methodology, as was recently proposed in the literature by Lelo et al. (2022). Moisture and cumulated feed rate are used as covariate. At the end, risk mitigation policy is suggested.
Originality/value
In this paper, the proposed methodology yields a dynamically calculated quantified risk, which emphasised the imperative for mitigating the risk, as well as presents a number of mitigation options, to quantifiably affect such mitigation.
Details
Keywords
Wei-Mon Yan, Hsu-Yang Teng, Chun-Han Li and Mohammad Ghalambaz
The electromagnetic field and cooling system of a high power switched reluctance motor (SRM) are studied numerically. The geometry of the motor and its main components are…
Abstract
Purpose
The electromagnetic field and cooling system of a high power switched reluctance motor (SRM) are studied numerically. The geometry of the motor and its main components are established using a computer-aided design software in the actual size. This study aims to evaluate the resulting thermal losses using the electromagnetic analysis of the motor.
Design/methodology/approach
In the electromagnetic analysis, the Joule’s loss in the copper wires of the coil windings and the iron losses (the eddy currents loss and the hysteresis loss) are considered. The flow and heat transfer model for the thermal analysis of the motor including the conduction in solid parts and convection in the fluid part is introduced. The magnetic losses are imported into the thermal analysis model in the form of internal heat generation in motor components. Several cooling system approaches were introduced, such as natural convection cooling, natural convection cooling with various types of fins over the motor casing, forced conviction air-cooled cooling system using a mounted fan, casing surface with and without heat sinks, liquid-cooled cooling system using the water in a channel shell and a hybrid air-cooled and liquid-cooled cooling system.
Findings
The results of the electromagnetics analysis show that the low rotational speed of the motor induces higher currents in coil windings, which in turn, it causes higher copper losses in SRM coil windings. For higher rotational speed of SRM, the core loss is higher than the copper loss is in SRM due to the higher frequency. An air-cooled cooling system is used for cooling of SRM. The results reveal when the rotational speed is at 4,000 rpm, the coil loss would be at the maximum value. Therefore, the coil temperature is about 197.9°C, which is higher than the tolerated standard temperature insulation material. Hence, the air-cooled system cannot reduce the temperature to the safe temperature limitation of the motor and guarantee the safe operation of SRM. Thus, a hybrid system of both air-cooled and liquid-cooled cooling system with mounting fins at the outer surface of the casing is proposed. The hybrid system with the liquid flow of Re = 1,500 provides a cooling power capable of safe operation of the motor at 117.2°C, which is adequate for standard insulation material grade E.
Originality/value
The electromagnetic field and cooling system of a high power SRM in the presence of a mounted fan at the rear of the motor are analyzed. The thermal analysis is performed for both of the air-cooled and liquid-cooled cooling systems to meet the cooling demands of the motor for the first time.
Details
Keywords
Mixtures of metallic phosphates which are produced as by‐products of the phosphate industry have been found to have superior corrosion‐inhibiting properties in water systems while…
Abstract
Mixtures of metallic phosphates which are produced as by‐products of the phosphate industry have been found to have superior corrosion‐inhibiting properties in water systems while at the same time preventing scale deposition in those sections where the water has a tendency to form scales. Thus, chemical control of acidity in water systems becomes much less critical. The new technique is considered important and it is thought that metallic phosphates may in the future be applied to fields other than water treatment. The following article is based on the results of work carried out in the laboratories of the Deady Chemical Co., Kansas City, U.S.A.
Ioannis A Kartsonakis, Elias P. Koumoulos, Antonis Karantonis, Costas A. Charitidis, S Dessypris and A Monos
The purpose of this paper is to perform the evaluation of copper susceptibility to corrosion in industrial cooling systems. Microstructure and defects of copper are observed…
Abstract
Purpose
The purpose of this paper is to perform the evaluation of copper susceptibility to corrosion in industrial cooling systems. Microstructure and defects of copper are observed, while divergences from optimum structure are discussed.
Design/methodology/approach
Various types of corrosion are examined. Electrochemical techniques such as electrochemical impedance spectroscopy and potentiodynamic polarisation are applied in these materials, using corrosion inhibitors. Microscopic observations and electrochemical measurements are interpreted according to possible mechanistic scenarios.
Findings
It is evident that, under specific conditions (e.g. high pH), water cooling ingredients can enhance corrosion, leading to significant copper mass loss from the inner surface of the pipe and thus leading to failure.
Originality/value
Evaluation of copper corrosion in cooling industrial systems was done, as well as studies of copper corrosion in sodium chloride.
Details