• International Journal of High-Rise Buildings
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• v.12 no.4
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• pp.335-341
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• 2023

This study proposes a novel rotary direct evaporative cooler and investigates the potential of a moisture-wicking fabric as a cooling pad for the proposed evaporative cooler. The rotary direct evaporative cooler rotates the cooling pad to reduce the water and energy consumption of the pump compared to those of existing direct evaporative coolers. A moisture-wicking fabric is considered as the material of the cooling pad, because of its high moisture-wicking property, enhancing water evaporation. Experiments are performed under various inlet air conditions while measuring the air temperature, relative humidity, air velocity, and differential pressure. The evaporative cooling efficiency and impacts of the inlet air temperature and air velocity on the cooling performance are also evaluated. The results demonstrate the potential of the moisture-wicking fabric as cooling pad of direct evaporative cooler.

• Tribology and Lubricants
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• v.30 no.5
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• pp.265-270
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• 2014

Frictional heat greatly influences the friction behaviors during clutch engagement. Therefore, the engagement of a wet or dry clutch is frequently not under control by the frictional heat. In a wet clutch, the frictional temperature also specially needs to be controlled, and in many cases, the clutch material is selected to prevent a temperature rise from the friction between friction pad and separator. However, only the selection of the clutch material cannot ensure sufficient control of the temperature rise by the friction. The groove pattern on a friction pad is designed for more flow rates of transmission fluid between the contact gap of clutch pad and separator for the cooling effect. In this work, grove patterns are designed for more flow rates out of the contact gap between friction pad and separator plate. Selected groove design shows the improvement flow rates of transmission fluid through both inner and outer radius, where most of the transmission fluid flows through the outer radius when the clutch is engaged due to the centrifugal force in conventional wet clutch groove. Several comparisons of the amounts of frictional heat generated on clutch pads are made in order to verify the decrease of the temperature rise according to the flow rates along the groove patterns.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.07a
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• pp.193-194
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• 2005

By the high-temperature pad conditioning process: The slurry residues in pores and grooves of the polishing pad were clearly removed. These clear pores and enlarged grooves made the slurry attack the oxide surface. The changed slurry properties by high-temperature pad conditioning process made the oxide surface hydro-carbonate to be removed easily.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.6
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• pp.45-51
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• 2005

Braking performance of a vehicle can be significantly affected by the temperature increment in the brake system. Therefore, the important problem in brake system is to reduce the thermal effect by friction heat. Recently, many studies have been performed and good results have been reported on the prediction of the brake disk temperature. However, the study on the pad, piston and brake fluid temperature is rarely found despite of its importance. In this study, the temperature distribution of the disc brake system is studied according to the material properties of brake piston. Vehicle deceleration, weight distribution by deceleration, disc-pad heat division and the cooling of brake components are considered in the analysis of heat transfer. Unsteady state temperature distributions are analyzed by using the finite element method and the numerical results are compared with the experimental data.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.20 no.10
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• pp.839-845
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• 2007

In this paper, a polishing pad has been analyzed in detail, to understand surface phenomena of polishing process. The polishing pad plays a key role in polishing process and is one of the important layer in polishing process, because it is a reaction layer of polishing[1]. Pad surface physical property is also ruled by pad profile. The profile and roughness of pad is controlled by different types of conditioning tool. Conditioning tool add mechanical force to pad, and make some roughness and profile. Formed pad surface will affect on polishing performance such as RR (Removal Rate) and uniformity in CMP Pad surface condition is changed by conditioning tool and dummy run and is stable at final. And this research, we want to reduce break-in and dummy polishing process by analysis of pad surface and artificial machining to make stable pad surface. The surface treatment or machining enables to control the surface of polishing pad. Therefore, this research intends to verify the effect of the buffing process on pad surface through analysis of the removal rate, friction force and temperature. In this research, urethane polishing pad which is named IC pad(Nitta-Haas Inc.) and has micro pore structure, is studied because, this type of pad is most conventional type.

• Journal of Bio-Environment Control
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• v.14 no.2
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• pp.76-82
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• 2005

Evaporative cooling pad system is one of the main cooling methods in greenhouses and its efficiency is very high. However, it has some disadvantages such as greenhouse temperature distributions are not uniform and installation cost is expensive. In this study, a CFD simulation model f3r predicting the air temperature distribution in the fan and fad cooling greenhouse was developed. The model was calibrated and validated against experimental data and a good fit was obtained. The influence of different outside wind, fan and pad height, ventilation rate, shading, and greenhouse length, were then examined. In order to reduce the internal temperature gradients, it is desired that the prevail wind direction and the fan and pad heights are considered. The simulation indicates that high ventilation rates and shading contribute to reduce the temperature gradients in the fan and pad cooling greenhouse. In order to maintain the desired greenhouse temperature, the pad-to-fan distance should be restricted according to the design climate conditions, shading and ventilation rates. The developed CFD model can be a useful tool to evaluate and design the fan and pad systems in the greenhouses with various configurations.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2005.11a
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• pp.352-353
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• 2005

Indium tin oxide (ITO) thin film was polished by chemical mechanical polishing (CMP) immediately after pad conditioning with the various conditioning temperatures by control of do-ionized water (DIW). Light transparent efficiency of ITO thin film was improved after CMP process after pad conditioning at the high temperature because the surface morphology was smoother by soften polishing pad and decreased particle size.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 2003.11a
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• pp.261-266
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• 2003

The present paper theoretically investigates characteristics of moment balance of a tilting-pad thrust bearing. Pressure of lubricant film of the bearing was computed using tile finite element method, and average film temperature was estimated from the heat balance over a pad. From the investigation, it has been found that different two sets of tilt angles satisfy moment equilibrium of the pad about tile pivot for a given pivot location. The tilt angles converged depend upon initial tilt angles assumed. Quite different bearing performance, including load capacity, film thickness, and temperature, is shown to be obtained based on choice of the initial tilt angles.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.2
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• pp.26-31
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• 2011

This article provides the systematic design methodology for a tilting pad journal bearing. First the dynamic factors for the bearing are selected with the critical speed analysis. The pad bearing is then designed to have its best mechanical efficiency by simulations with changing of the number of pad and the lubricant flow rate with meeting the design specifications such as metal temperature, clearance and so on. And the simulation results are reviewed to compare with an experimental test. Finally the stability of rotor with the designed bearing is investigated. This methodology is successfully applied to the rotor for 1.2MW turbo-blower.

• Tribology and Lubricants
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• v.20 no.3
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• pp.152-156
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• 2004

The present paper theoretically investigates characteristics of moment balance of a tilting-pad thrust bearing. Pressure of lubricant film of the bearing was computed using the finite element method, and average film temperature was estimated from the heat balance over a pad. From the investigation, it has been found that different two sets of tilt angles satisfy moment equilibrium of the pad about the pivot for a given pivot location. The tilt angles converged depend upon initial tilt angles assumed. Quite different bearing performance, including load capacity, film thickness, and temperature, is shown to be obtained based on choice of the initial tilt angles.