• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2006년도 춘계학술대회 논문집
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• pp.383-384
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• 2006

Ventilated disc was improved for reducing judder and heat. But the crack among vent holes occurs due to stress concentration. We investigate the stress distribution of vent holes. The vent holes with shape of a right angle, a chamfer and rounding was analyzed. The result of FEA was that rounded vent holes have a minimum stress. Also Maximum stress distributed within holes. Therefore We suggest that the rounded vent holes is good to reduce the crack.

• 한국가시화정보학회:학술대회논문집
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• 한국가시화정보학회 2006년도 추계학술대회 논문집
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• pp.17-20
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• 2006

Passenger safety is fundamental factor in automobile. Among much equipment for passenger safety, the air bag system is the most fundamental and effective device. Beside of the front air bag system which installed on most of all automobiles, a curtain-type air bag is increasingly adapted in deluxe cars fur protecting passengers from the danger of side clash. Curtain type airbag system consists of inflator housing, fill hose, curtain airbag. Inflator housing is a main part of the curtain-type air bag system for supplying high-pressure gases to deploy the air bag-curtain. Fill hose is a passageway to carry the gases from inflator housing to each part of curtain airbag. Therefore, it is very important to design the vent holes of fill hose for good performance of airbag deployment. But, the flow information from vent holes of fill hose is very limited. In this study, we measured instantaneous velocity fields of a high-speed flow ejecting from the vent holes of fill hose using a dynamic PIV system. From the velocity Held data measured at a high frame-rate, we evaluated the variation of the mass flow rate with time. From the instantaneous velocity fields of flow ejecting from the vent holes in the initial stage, we can see a flow pattern of wavy motion and fluctuation. The flow ejecting from the vent holes was found to have very high velocity fluctuations and the maximum velocity was about 480m/s at 4-vent hole region. From the mass flow rate with time, the accumulated flow of 4-vent hole has occupied about 70% of total flow rate.

• 한국CDE학회논문집
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• 제14권5호
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• pp.330-337
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• 2009

Nowadays a lot of high-tech electronic products such as TVs, monitors and camcorders are being developed. The more functions the electronic devices have, the more heat problems occur. Therefore, most of electronic products have air-ventilation holes to eliminate heat that is generated inside the products. The shapes of ventilation holes are usually complicated since aesthetic appearance of the products is important these days. In order to create those complicated shapes, designers should do time-consuming jobs because most of commercial CAD systems do not provide the functions that create patterns of lofted parts along freeform surfaces. In this research, an automated air-ventilation hole modeling system was proposed. The system generates patterns of lofted objects on freeform surfaces. Standard process to create air-ventilation holes manually was established, and vent-hole types and pattern types were classified into several categories. Designers can create many kinds of vent-holes by combining vent-hole types and pattern types. Users can also utilize user-defined pattern which can give users more flexibility. Developed system was applied to several design examples and the results are presented.

• Journal of Biosystems Engineering
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• 제20권4호
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• pp.360-367
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• 1995

The effect of air vent holes, stacking methods of boxes and clearance between boxes on static pressure drop, were measured to design of pressure cooling system. Static pressure drops in air vent hole of carton box were measured for different hole opening ratio from 1% to 5%. Static pressure drop was expressed as a function of superficial velocity as second-degree polynomial. At given static pressure in plenum chamber, static pressure drop in boxes was shown as second-degree polynomial of the number of carton box in series stacking method, as first-degree polynomial in height and parallel stacking method. In pressure cooling of 24 boxes of Tsugaru apple, air flow rates through clearance between the boxes were shown 1.27 and 1.65 times than those of through the inside of boxes at the plenum pressure of 10mmAq and 20mmAq, respectively.

• 한국정보통신학회논문지
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• 제11권6호
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• pp.1141-1149
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• 2007

본 논문에서는 신발금형의 가스벤트 착탈 작업을 효율적으로 진행하기 위해 이미지 프로세싱을 통한 가스벤트 착탈위치 탐색과 정밀 제어로 착탈 작업을 수행하는 교환 장치의 두 가지 기술을 다루고 있다. 이 두가지 방법을 적용하기 위한 핵심적인 이슈는 신발 금형의 가스벤트 교환 위치의 중심을 어떻게 하면 정확하게 찾아내는가이다. 이러한 자동 교환 장치의 사용은 가스벤트 착탈 시간을 줄이며 아울러 노동력의 절감 제품의 생산에 드는 비용을 최소화하는 등의 여러 가지 이점을 가져다 준다. 이 장치를 사용하여 실험을 통해 검증한 결과 가스벤트 교환 장치의 사용이 더 안정적이고 효율적이며 착탈 시간을 줄여 공정시간을 단축하는 것을 증명할 수 있었다.

• 한국농업기계학회:학술대회논문집
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• 한국농업기계학회 1996년도 International Conference on Agricultural Machinery Engineering Proceedings
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• pp.896-905
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• 1996

Pressure drop, as a function of air flow, was measured for tomatoes and mandarins in bulk with different sizes, stacking arrangements and bed porosities. Pressure drop was also measured on carton vent holes and on a carton of packed fruits . and the cumulative effects of air flow resistance of vent holes and packed fruits in bulk on the air flow resistance of a carton of fruits were evaluated . Equation were presented to describe pressure drop bulk fruits, of an empty carton and of a carton of packed fruits as related to the air velocity , the bed porosity, the fruit diameter and the opening ratio of the vent hole.

• 한국화재소방학회논문지
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• 제26권5호
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• pp.99-104
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• 2012

본 연구에서는 공동주택 화재 시 피난시나리오 및 화재실 배연개구부 유무에 따른 부속실 급기가압 시스템의 성능 및 효용성을 평가하기 위해 각 실의 압력변화 특성을 실험적으로 측정하였다. 그 결과, 화재실문과 계단실문 개폐 시나리오 및 배연개구부의 유무에 따라 압력변화 특성이 크게 달라졌으며 최저설계차압으로 재안정화 되기 전에 부속실 과압 또는 부압 발생, 도어클로져 닫힘 기능 저하 등의 현상이 나타났다. 또한. 급기댐퍼의 설치위치보다는 화재실 배연개구부의 존재가 규정방연풍속 유지에 필수적인 것으로 나타났다.

• 센서학회지
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• 제15권1호
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• pp.20-27
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• 2006

This paper presents a gas measurement system for deciding hole positions on a PU middle-sole mold from computed gas amount. The optimal number of holes and their positions on the shoe mold are decided from statistical experiment results to overcome the problem of excessive expenses in gas vent exchange. This paper also describes a gas vent exchange mechanism using computer vision system. The gas hole detecting process is based on computer vision algorithms represented as a simple Pattern Matching. The experimental result showed us that the system was useful to calculate the number of holes and their positions on the shoes mold.

• 항공우주기술
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• 제4권1호
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• pp.150-161
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• 2005

발사체의 노즈 페어링 벤트 홀 크기 결정 기법의 정확도를 검증하기 위한 시험을 수행하였다. 한국항공우주연구원 우주비행시험그룹이 보유한 열진공 챔버(Bake-Out Chamber)를 이용하여 챔버 내부 압력을 대기압에서 진공으로 떨어뜨렸으며, 그 속에 다양한 벤트홀이 설치된 모델을 넣고 모델 내외부의 압력 및 온도 변화를 측정하였다. 시험 과정에서 나타난 시험 설비 및 측정 장비의 특성을 검토하고 이들이 얻어진 시험 데이터의 정확도 및 신뢰도에 미치는 영향을 분석하였다. 설비 및 측정 장비의 한계 내에서 최대한의 정확도를 얻을 수 있도록 데이터를 처리하였으며, 이렇게 얻어진 시험 결과로부터 벤트 홀 면적 및 배치에 따르는 영향을 분석하였다.

• 소성∙가공
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• 제20권5호
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• pp.377-386
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• 2011

During stamping processes, the air trapped between sheet metal and the die cavity can be highly compressed and ultimately reduce the shape accuracy of formed panels. To prevent this problem, vent holes and passages are sometimes drilled into the based on expert experience and know-how. CAE can be also used for analyzing the air behavior in die cavity during stamping process, incorporating both elasto-plastic behavior of sheet metal and the fluid dynamic behavior of air. This study presents sheet metal forming simulation combined simultaneously with simulation of air behavior in the die cavity. There are three approaches in modeling of air behavior. One is a simple assumption of the bulk modulus having a constant pressure depending on volume change. The next is the use of the ideal gas law having uniform pressure and temperature in air domain. The third is FPM (Finite point method) having non-uniform pressure in air domain. This approach enables direct coupling of mechanical behavior of solid sheet metal and the fluid behavior of air in sheet metal forming simulation, and its result provides the first-hand idea for the location, size and number of the vent holes. In this study, commercial software, PAM-$STAMP^{TM}$ and PAM-$SAFE^{TM}$, were used.