• 한국연소학회:학술대회논문집
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• 한국연소학회 2002년도 제25회 KOSCI SYMPOSIUM 논문집
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• pp.57-64
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• 2002

This paper describes the results of a series of experiments executed by using two pilot-scale oxv-fuel burners are designed for maximum capacity of 50,000 kacl/hr, 300,000 kcal/hr and installed in the test furnace. The effects of turn-down ratio, excess oxygen ratio, nozzle exit velocity, injection angle, swirl vane angle and inlet oxygen temperature on the combustion characteristic are investigated. Temperature distributions are measured using R-type and Molybdenum sheathed C-type thermocouple. The results showed that maximum temperature and mean temperature increase with the increase of turn-down ratio and inlet oxygen temperature. The maximum flame temperature was increased about 35% compared to the case of equivalent air operated condition. In addition, Optimum excess oxygen ratio and nozzle characteristics are obtained for this oxy-fuel glass melting furnace.

• 한국연소학회지
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• 제5권2호
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• pp.63-68
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• 2000

Combustion phenomenon in scale-downed combustor is investigated. As the combustor scale decreases surface to volume ratio increases and chamber size approaches quenching distance. As the combustor scales down surface to volume ratio increases resulting increased heat loss. And this heat loss can affect quenching and instability of the flame. To investigate this effect plastic mini combustor is made. Stoichiometricaly premixed Hydrogen / air gas is used as fuel. Initial chamber pressure and chamber size are varied and the effects are evaluated. Peak pressure decreased with the decrease in chamber height. As initial chamber pressure decreases peak pressure decreases and this change is more important than scale down effect till the chamber height of 1mm. With this result and further information following the experiments design parameter for micro engine can be established.

• 한국융합학회논문지
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• 제4권3호
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• pp.1-5
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• 2013

본 연구에서는 소형풍력발전용 블레이드의 축소모델을 대상으로 단순 하중 계산 및 구조 시험을 수행하였다. 먼저, 연구 대상인 블레이드의 초기 모델의 0.2 비율만큼 축소하여 설계 및 제작하였다. 그리고 소형 풍력발전 국제 규격인 IEC 61400-2에 의거한 단순 하중 계산식을 이용하여 모멘트를 획득하였다. 또한, 추를 이용한 구조시험을 수행하여 최대 모멘트를 획득하였다. 이를 통하여 계산 및 시험에 따른 최대 모멘트를 비교하였다.

• Wind and Structures
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• 제11권4호
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• pp.291-302
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• 2008

Three-dimensional engineering simulations of momentum-driven tornado-like vortices are conducted to investigate the flow dynamics dependency on swirl ratio and the possible relation with real tornado Fujita scales. Numerical results are benchmarked against the laboratory experimental results of Baker (1981) for a fixed swirl ratio: S = 0.28. The simulations are then extended for higher swirl ratios up to S = 2 and the variation of the velocity and pressure flow fields are observed. The flow evolves from the formation of a laminar vortex at low swirl ratio to turbulent vortex breakdown, followed by the vortex touch down at higher swirls. The high swirl ratios results are further matched with full scale data from the Spencer, South Dakota F4 tornado of May 30, 1998 (Sarkar, et al. 2005) and approximate velocity and length scales are determined.

• 융합정보논문지
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• 제7권5호
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• pp.83-88
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• 2017

본 논문은 F-16 전투기 축소모델을 사용한 위상비교 방향 탐지 장치의 방위각 정확도 시험에 대해서 기술하였다. 전투기 하부면에 안테나를 배치하면 항공기 구조물에 의한 전파 반사가 일어나서 방위각 측정오차가 발생한다. 본 연구에서는 F-16 전투기를 5:1로 축소 모델링하고 전투기 하부면에 5개 안테나를 원형으로 설치한 다음 $0-360^{\circ}$ 방위각에서 $1^{\circ}$ 간격으로 전파를 수신하였다. 이 때 5개 안테나에 수신되는 전파의 위상을 수치해석으로 계산하여 방향 탐지정확도 시험을 실시하였다. 축소모델을 사용해서 시험한 위상비교 방향 탐지 방식의 방위각 오차는 신호잡음세기가 0dB 이상인 경우 평균 $0.5^{\circ}$ 이하로 측정되어서 전투기의 위상비교 방향 탐지 장치 설계에 유용하게 활용할 수 있을 것으로 판단된다.

• 한국정밀공학회지
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• 제24권3호
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• pp.108-116
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• 2007

To overcome many defects such as the high product cost, large energy consumption, and big space capacity in conventional mechanical machining, the miniaturization of machine tool and micro factory systems has been envisioned recently. The object of this paper is to research the effect of dynamic characteristic parameters in bolted-joint beams, which is widely applied to the joining of mechanical structures in order to identify structural system characteristics and to predict dynamic behavior according to scale-down from macro to micro system as the development of micro/meso-scale machine tool and micro factories. Modal parameters such as the natural frequency, damping ratio, and mode shape from modal testing and dynamic characteristics from finite element analysis are extracted with all 12 test beam models by materials, by size, and by joining condition, and then the results obtained by both methods are compared.

• 한국연소학회지
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• 제9권1호
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• pp.1-10
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• 2004

The results of a series of experiments executed by using two pilot-scale oxy-fuel burners are presented. The oxy-fuel burners are designed for maximum capacity of 50,000kcal/hr, 200,000kcal/hr and installed in the test furnace. The effects of turn-down ratio, excess oxygen ratio, nozzle exit velocity, injection angle, and swirl vane angle on the combustion characteristic are investigated. Temperature distributions are measured using R-type and Molybdenum sheathed C-type thermocouple at various points of the flame. The results showed that maximum temperature and mean temperature increase with the increase of turn-down ratio and momentum. The maximum flame temperature was increased about 35% compared to the case of equivalent air operated condition. In addition, optimum burner type, excess oxygen ratio and nozzle characteristics are obtained for this oxy-fuel glass melting furnace.

• 한국구조물진단유지관리공학회 논문집
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• 제13권1호통권53호
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• pp.135-144
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• 2009

본 연구에서는 현장타설과 프리캐스트 방식의 콘크리트 충진 FRP 교각의 성능평가 실험을 수행하였다. 8개의 축소모형 실험체에 대한 준정적 실험을 실시하였으며, 실험변수로는 FRP 두께, 콘크리트 강도, 횡방향 철근비, 직경을 선정하였다. 반복 횡하중에 대한 연성능력을 평가하고 각 시험체의 강성저하에 따른 감쇠비와 파괴양상 등을 비교하였다.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2000년도 제21회 KOSCO SYMPOSIUM 논문집
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• pp.212-216
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• 2000

Combustion phenomenon in scale-downed combustor is investigated. As the combustor volume decreases surface to volume ratio increases. for increased surface to volume ratio means increased heat loss and this increased heat loss affects reaction in combustion chamber. Plastic mini combustor is made. Stoichiometricaly premixed Hydrogen I air gas is used as fuel. Initial chamber pressure and chamber size are varied and the effects are evaluated. Peak pressure decreases with the decrease in chamber height. As initial chamber pressure decreases peak pressure decreases. And this change is more important than scale down effect till the chamber height of 1mm. With this result and further information following the experiments design parameter for micro engine can be established.

• 조명전기설비학회논문지
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• 제25권12호
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• pp.11-20
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• 2011

PSALI is referred to the supplementary lighting for the interior lighting under the daily lighting situation, and pursuant to the pertinent regulations in energy savings design standard and others in recent architecture works, the importance thereof has been increasing gradually coupled with the energy performance index (EPI), energy savings plan and the like as well as expansion of submittal and implementation policies. However, this type of PSALI studies indeed have a number of limitations since it has surrounding environmental conditions in direction, season, region, climate, time, opening rate, window area ratio, actual index, reflection rate of finishing materials and others in the architecture work as well as frequent changes in interior lighting environment for variables in daily light volume flowing into the interior, and others. Therefore, this study has analyzed existing advance research cases to produce the actual-sized model and scaled-down model, and installed the artificial lighting of LED light source possible to reproduce with same capability on both models. As a result of comparison and analysis of the artificial lighting with the key light, it has certain level of error rate from the scaled down lighting device in certain rate and actual model butit was noticeably significant within specific scope.