• Journal of the Korean Society of Combustion
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• v.19 no.4
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• pp.8-13
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• 2014

Flow distribution of fuel nozzles for a combustor in a micro gas turbine is numerically investigated. The fuel supply system for the present study has 12 single nozzles with a diameter of several hundred micrometers. A uniform temperature distribution of a combustor outlet should be achieved for maximizing the lives of the turbine blades and nozzle guide vanes. For this, it is very important to uniformly supply fuel to a combustor. In order to investigate flow distributions of fuel nozzles, numerical models for fuel nozzles are made and solved by a commercial code, ANSYS FLUENT. An effect of a fuel nozzle diameter and fuel flow rates on flow distribution of fuel nozzles is numerically investigated. As a result, non-uniformity is increasing as a diameter of a single fuel nozzle increases. Finally, an appropriate diameter of a single fuel nozzle is suggested.

• Transactions of the Korean hydrogen and new energy society
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• v.26 no.2
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• pp.136-147
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• 2015

Dead-ended operation of Proton Exchange Membrane Fuel Cell(PEMFC) provides the simplification of fuel cell systems to reduce fuel consumption and weight of fuel cell. However, the water accumulation within the channel prohibits a uniform supply of fuel. Optimization of the purge strategy is required to increase the fuel cell efficiency since fuel and water are removed during the purge process. In this study, we investigated the average voltage output which depends on two interrelated conditions, namely, the supply gas pressure, purging valve open time. In addition, flow visualization was performed to better understand the water build-up on the anode side and cathode side of PEMFC in terms of a variety of the current density. We analyzed the correlation between the purge condition and water flooding.

• Journal of the Korean Society for Precision Engineering
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• v.34 no.2
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• pp.101-106
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• 2017

The chemical mechanical planarization (CMP) process combines the chemical effect of slurry with the mechanical effect of abrasive (slurry)-wafer-pads The slurry delivery system has a notable effect on polishing results, because the slurry distribution is changed by the supply method. Thus, the investigation of slurry pumps and nozzles with regard to the slurry delivery system becomes important. This paper investigated the effect of a centrifugal slurry pump on a spray nozzle system in terms of uniform slurry supply under a rotating copper (Cu) wafer, based on experimental results and computational fluid dynamics (CFD). In conventional tools, the slurry is unevenly and discontinuously supplied to the pad, due to a pulsed flow caused by the peristaltic pump and distributed in a narrow area by the tube nozzle. Adopting the proposed slurry delivery system provides a higher uniformity and lowered shear stress than usual methods. Therefore, the newly developed slurry delivery system can improve the CMP performance.

• Nuclear Engineering and Technology
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• v.10 no.2
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• pp.79-86
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• 1978

The object of this study was to obtain data on air-distributions in two-phase up flow in vertical rod-bundle test-section. The test-section in this study was a hexagonal shaped 61-rod bundle where each rod was wrapped with helical spacers. The variables were flow rates of air and water and air inlet positions. Experimental data were obtained at the outlet of the test-section. The experiments were performed in two parts. Firstly, data were taken at increasing flow rates of air keeping water flow rates constant, and secondly, at simultaneous increase of air and water flow rates. At each flow condition, air supply position could be changed to 4 different positions. Data obtained by electrical void-needle technique were analyed and are presented here in graphical forms for comparison. The results of this study demonstrate qualitatively that air-distribution tends to be more uniform as water flow rates are increased. The air supply positions have noticeable effects on the pattern of air-distribution.

• The Journal of the Convergence on Culture Technology
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• v.4 no.1
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• pp.237-240
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• 2018

Recently, many parts including military uniform and combat boots have been changed into functional ones in company with the development of military supplies. Especially, problems such as crack of soles and defective boots regarding combat boots have been improved, which is the motive of this study. As a result of verifying other theses, the study on the satisfaction of combat boots is not existent. The contents of study are the pressure of combat boots, the analysis on the shoelace of combat boots as the instrument for suicide and they are not interesting, which is the reason to become a subject of this study.

• Journal of agriculture & life science
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• v.44 no.3
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• pp.7-14
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• 2010

Alternative subirrigation way, capillary wick system (CWS) was tested to reduce labor cost, waste water, contamination of ground water, and use of fungicide compared to overhead irrigation system (OIS). CWS helped reduce remarkably the working hours for watering from 4 hours in OSI to just 5 minutes. Labor cost was saved 98% in CWS compared to OIS. By the physical characteristics of various growing media, 1 coconut coir+2 perlite (v/v) mixture was selected because it had an ideal distribution of three phase, e.g. 1 solid: 1 liquid: 2 gas phase. Medium mixture containing scoria had so high bulk and particle density to hurt root. In bark-containing medium, the liquid phase and the percent saturation of liquid phase with time elapsed was lower than that of other mixture. It meant that the mixture contained very low level of water. Application of CWS for cyclamen pot production played an important role in reducing the incident of fusarium wilt symptom from 18% in conventional over watering system to 4%. Cyclamen pot irrigated by capillary wick had shorter petiole and more leaves than those by overhead watering. As a result, this system was highly beneficial to get uniform pot products with high quality. It improved water and nutrient solution efficiency relative to conventional overhead irrigation system (OIS).

• The Journal of Society for e-Business Studies
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• v.17 no.1
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• pp.151-171
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• 2012

In applying RFID/USN technology to various industries, it is needed to solve the problem caused by the system differences. Accordingly, this study introduces the common standard platform concept, and suggests the standard data scheme which provides the uniform perspective of classifying supply chain data and of using vocabularies. We selected several industry areas applicable for the platform, which are pharmaceutical, cosmetics, food and liquor industry. We collect and organize terminologies used in the supply chain of each industry, and then classify them according to the defined data attributes. The standardized vocabularies are suggested based on the contextured scheme of data classification. This study could provide more convenient way of communication between business partners, system developers and users of the platform.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.17 no.4
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• pp.370-376
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• 2005

For the purpose of investigating the effective removal of heating/cooling load from light-weighted building envelope, two air-conditioning systems, conventional parameter air-conditioning system and air-barrier system, are evaluated and compared by both experiment and simulation with six different cases during heating and cooling season. In addition, the characteristics of window-side building thermal load are assessed by varying supply air velocity in order to seek the optimal system operation condition. The results are as follows. 1) Air-barrier system is more effective to remove heating/cooling load at perimeter zone than conventional parameter air-conditioning system. Moreover, the better effectiveness appears during cooling season than during heating season. 2) The experiment during cooling season provides that indoor temperature of air-barrier system shows $1^{\circ}C$ less than that of the conventional system with similar outdoor air temperature profile, and indoor temperature distribution is more uniform throughout the experimented model space. It concludes that air-barrier system can achieve energy saving comparing to the conventional system. 3) The capturing efficiency of air-barrier system is 0.47 on heating season and 0.2 on cooling season with the same supply air volume. It results that the system performs effectively to remove building thermal load, moreover demonstrates high efficiency during cooling season. 4) The simulation results provide that capturing efficiency to evaluate the effective removal of building load from perimeter zone shows high value when supply air velocity is 1 m/s.

• Journal of Families and Better Life
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• v.22 no.5
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• pp.59-73
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• 2004

Since 1980s' Korea had a great change on the housing culture by the supply of multi-family housing stock both on the macro-social and micro-social aspects. The purpose of this study was to examine the changes and the characteristics of housing environments which were estimated its modernization, and to examine the personal life under the change of housing environments. So I would like to revaluation the characteristics of modernization between the 1980s' and 1990s'. Therefore references were made to various papers, reports, the statistical data, newspaper reports, advertisements and magazines during that period. As a result, this paper came to the remarks as follows: 1. The success of modernization on the housing environments since 1980s' was the Quantitative growth of housing supply by multi-family housing. In spite of this, the Quantitative growth of housing supply and the improvement in Quality like housing space per person had the characters which was 'out of valence on the division'. 2. The Qualitative improvement of modem housing life by the development of housing industries could be said the improvement owing to develop of facilities and equipments. The introduction of up-to-date facilities and equipments realized the convenience and the rationality of living in the house. Although the improvement on the physical things deteriorated the modernized spaces to uniform things by commercial strategies. 3. The life in the multi-family housing which gives protection to personal privacy was settle down on the extremely individualized life without common things within the neighbors. Multi-family housing which was a production of process of modernization came true the growth in an appearance and the variety in the inside, but for the aspect of residents' everyday life in the multi-family housing, the Korean traditional relationship was collapsed and a sense of incompatibility within the residents was created.

• Journal of Power System Engineering
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• v.10 no.3
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• pp.32-37
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• 2006

In this paper, we present the flow and heat transfer characteristics with the array of impinging jet nozzles by using the numerical computation and experiment. Numerical solutions were obtained for dimensionless gap H=6, dimensionless outlet length L=10 and Reynolds number Re=1500 by using the commercial CFD code, CFX-5. Experimental and numerical results were agreed well with each other. It was found that the impinging jet with circular array nozzles generated the uniform heat transfer area and the maximum heat transfer is higher than rectangular array nozzles for certain parameter sets. It is one of the most important utilities providing steam to turbine in order to supply mechanical energy in thermal power plant. It is composed of thousands of tubes for high efficient heat transfer.