• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2017년도 춘계 학술논문 발표대회
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• pp.236-237
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• 2017

This study discusses the development of waterproofing layer jet-spray nozzle that forms a three-dimensional air cell. This nozzle has an air flow generation mechanism in the air groove of the attachment cell part located at the end of the injection nozzle. Since the air grooves also function as an air curtain, the airborne particles generated when the waterproof material is sprayed is effectively blocked. In the past, spraying of the waterproof material through the high pressure was possible, but this technology allows stable injection due to the static agitation method, and various problems caused by particle generation has been (damages to neighboring areas, economic loss, etc.) minimized.

• 대한설비공학회:학술대회논문집
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• 대한설비공학회 2007년도 동계학술발표대회 논문집
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• pp.252-257
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• 2007

The present study investigated the effect of air velocity on frost formation of slit fin-and-tube heat exchanger under frosting condition. The slit fin-and-tube heat exchanger with outer tube diameter 7.0mm and 1 row was used. Air side pressure drop, photographs of frost distribution, frost accumulation and frost thickness were presented with respect to the frosting time. In the early stage of experiment, the case with air velocity of 1.5m/s showed 403% higher for the air pressure drop than the case with the air velocity of 0.5m/s. As the frost was accumulated, the effect of air velocity on air pressure drop was decreased. In the end stage of test, air pressure drops of two cases were very close and air pressure drop for the air velocity of 0.5m/s was higher than that of 2.0m/s. It was also shown in the photographs of frost distribution, frost accumulation and frost thickness. From frost thickness, fanning friction factor was presented.

• 설비공학논문집
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• 제15권7호
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• pp.586-594
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• 2003

The performance of the condenser installed in the air-conditioning plant room of a high-rise building was studied numerically. The effect of the draft direction on the performance of an air-conditioner was analyzed. The on-coil temperature of the condenser was investigated by varying the arrangement and location o( the condenser in the air-conditioning plant room. The performance of an air-conditioner was also evaluated by using COP (coefficient of performance) and CGPI (condenser group performance indicator). The condenser in an air-conditioning plant room should be arranged in such a manner that the fan of the condenser is facing the outside of the building to exhaust the hot air directly, The model by which the condenser is located at the lower-left end of an air-conditioning plant room can prevent the hot air from reentering, and allow indrafting of fresh air. When the direction of draft is to the frontal face of the building, the performance of the condenser above 30th floor is degraded.

• Journal of the Korean Wood Science and Technology
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• 제14권1호
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• pp.45-54
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• 1986

A study was conducted to determine the physical properties related to drying characteristics, the seasonal air drying curves and the kiln drying schedule for taun lumber imported and utilized. This kiln drying schedule was found by oven drying and developed by pilot testing of green lumber and partially air dried lumber. The results of this study were as follows; 1. Average green specific gravity and standard deviation of heartwood lumber were 0.60${\pm}$0.03 and those of sapwood lumber were 0.64${\pm}$0.02. 2. Radial shrinkage from green to air dry and from green to oven dry were 3.05 percent and 5.96 percent respectively, and tangential shrinkage from green to air dry and to oven dry were 5.49 percent and 8.74 percent respectively. 3. Drying time for 25mm thick green lumber (50 percent moisture content) air dried to 30 percent moisture content were 14 days in springtime. 6 days in summertime, and 12 days in autumntime, whereas for 50mm thick lumber in 36 days in springtime, 18 days in summertime, 38 days in autumntime. 4. Kiln drying schedules developed by oven drying were T8-B3 for 25mm thick lumber and T5-B2 for 50mm thick lumber. 5. Kiln drying curves of green 25mm and 50mm thick lumber were similar to those of partially air dried lumber from the level of 30 percent average moisture content. Green 25mm thick lumber (55.7 percent moisture content) was dried to 9.3 percent moisture content in 101.5 hours and green 50mm thick lumber (65.6 percent moisture content) was dried to 11.5 percent moisture content in 526 hours. 6. End checking for green 25mm thick lumber occured in 49.6 percent moisture content and reached maximum amount in 27.6 percent moisture content and closed in 15.8 percent moisture content. 7. End checking for green 50mm thick lumber and partially air dried lumber developed and reached maximum amount earlier then for 25mm thick lumber. 8. Final moisture content of surface layer for 50mm thick lumber was one half of that of core, and moisture content equalized in the lumber after nine days of room conditioning. 9. Casehardening for 50mm thick lumber was slight and was conditioned after nine days of room stroage. 10. Drying defects, such as end checking and surface checking, were not observed and the quality of dry lumber was first.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1998년도 하계학술대회 논문집 A
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• pp.107-109
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• 1998

This paper presents mechanical analysis of gas turbine generator (113MVA, $3{\phi}$, 2P, 0.9PF, F class, 3600rpm, 60Hz, 13.8kV, 4.72kA, Air-Cooling) field coil deformation. Rotor end coil deformation is only appeared on turbine end but collector end coil is normal. Expansion direction of end coil is tangential not axial. Deformation appears more severe at top turn. Retaining ling is expanded by centrifugal force of coil and itself. In case friction coefficient between coil top surface and retaining ring insulation inner surface is small, coil end length ${\ell}$ does not change. However, in case friction coefficient big condition, coil end is expanded ${\Delta}{\ell}$ due to start and stop. Deformation is assumed about 30mm by watching photograph inner surface of retaining ring is coated by Teflon at manufacturing condition. Usually Teflon coating insulation surface is small friction coefficient. It's value 0.08${\sim}$0.15. However it's value exceeds more than 0.297. Since top turn deformation appears. The distortion and subsequent failure have occurred because of the lack of a sufficient slip-plane between the top field coil conductors and the inside surface of the retaining ring insulation on the turbine end of the field-winding.

• 대한환경공학회지
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• 제33권5호
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• pp.325-331
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• 2011

연소과정 중에 발생하는 질소산화물을 저감하는 기술인 MILD 연소에 대하여 연료노즐과 공기노즐의 위치와 공기유량을 변화하면서 나타나는 연소특성을 수치해석을 통하여 연구하였다. 본 연구의 MILD 연소로는 연료노즐과 공기 노즐 사이에 연소배기가스의 배출구가 있는 연소로를 이용하였다. 공기노즐은 8개, 연료노즐은 4개를 사용하였다. 연료노즐이 연소로 중앙 부근에 위치한 연소로의 경우에 공기유량이 적을 때는 연소반응대가 연료노즐에서부터 연소로 벽면으로 치우치게 되지만 공기유량이 커지면 연소반응대가 연료노즐 측에서 시작하여 연료노즐 상부로 형성된다. 공기노즐이 연소로 중앙부분에 위치한 경우에 공기유량이 적을 때는 연소반응대가 공기노즐 부근에서 시작하여 연소로 벽면으로 치우치지만 공기유량이 증가하면 연소반응대가 연료노즐 측으로 옮겨가게 된다. 두 가지 경우 모두 공기유량이 증가하면 연소반응대에서 최대온도가 증가하고 따라서 배기가스에서의 NOx 농도가 증가한다. 두 가지 노즐 위치에서의 NOx 생성을 비교해 보면 공기노즐이 연소로 중앙에 위치한 경우가 연료노즐이 연소로 중앙에 위치한 경우보다 NOx 농도가 현저히 적음을 알 수 있었다. 본 연구의 결과로부터 NOx 저감과 연료의 미연가스 배출을 감안할 때 공기노즐이 연소로 중앙에 위치하고 이론공기량에 해당하는 공기량을 분출할 때 NOx 생성에 가장 효과적임을 알 수 있었다.

• 한국항공운항학회지
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• 제16권4호
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• pp.35-40
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• 2008

There are many studies indicate that human is one of the major contributing factors to the aviation accident. To this end, the Human Factor of pilots and in flight operations has been a popular subject to be studied, however, not of the air traffic controllers. Recently, some States have started studying Human Errors in Air Traffic Control field, removal of the potential errors in advance and prevention of the similar errors. This study analyzed Human Errors in air traffic control in terms of LOSA of airlines, which has been actively studied. This study will contribute to safe Flight Operation and Air Traffic Control.

• 대한전기학회논문지
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• 제35권11호
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• pp.479-486
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• 1986

It is necessary to consider a rotor movement in dynamic analysis on the flux distribution of electric machinery by FEM. Therefore, if air-gap domain was subdivided into triangular elements, computation results contain errors due to variation of element shape in air-gap because the nodal points corresponding to the rotor are displaced in analyzing domain for the time difference. In order to reduce this errors, the paper presents a application of a Macro Air-gap Element that interpolation function is obtained analytically and a means to join it with linear triangular elements in the rotating machine or in the linear machine. At the end of paper, setting up analytic domain model, it compares analytic solution with the computation results of Macro Air-gap Element appliction and that of linear triangular element subdivision only to each cases of nodal displacement. And it carries out that errors due to variation of element shape are reduced effectively by application of a Macro air-gap element.

• 한국신재생에너지학회:학술대회논문집
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• 한국신재생에너지학회 2008년도 추계학술대회 논문집
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• pp.282-285
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• 2008

In this paper, the numerical analysis of the model without air-guide was carried out in wind power generator. From numerical results, the temperature rise was not satisfied for the class F insulation and the non-uniformity of temperature distribution was a wide difference in heating elements. To improve these problems, the air-guide was installed in front of the coil head of non-drive end(NDE). The short distance between coil head and air-guide was more effective than long distance in cooling performance. Compared to that of the preliminary design, it was found that the cooling performance of the modification design was improved about 12%.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2001년도 하계학술대회 논문집 D
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• pp.2455-2457
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• 2001

The Remote controlled air conditioner is to effectively suppress the peak load generated from air conditioners in summer. It is important that remote controlled air conditioners are operated well in the real field. Almost 3,200 remote controlled air conditioners has been distributed as of the end of June, 2001. This paper describes a development of the certification system for the air conditioners.