• 설비공학논문집
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• 제15권5호
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• pp.439-445
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• 2003

The purpose of this study is to suggest the improvement strategies for exhaust performance in composite kitchen hoods. The Exhaust only hood, the 2-way compensating hood and the 3-way compensating hood were selected, and the laboratory experiments were performed to compare the local exhaust efficiency and the indoor temperature distributions according to the variations of the hood type and supply/exhaust air velocity. The results of this study can be summarized as follows. The compensating hood has better performance than exhaust only hood in the aspect of local exhaust efficiency and temperature distribution. The 3-way compensating hood shows the best performance when the supply air velocity is about 2.7 m/s, and the 2-way compensating hood at the supply air velocity of 3.5 w/s. In the same exhaust rate condition, if the exhaust area of the hood is increased and therefore the exhaust velocity is lowered, the supply air velocity is also lowered to get the optimum performance. The optimum exhaust velocity range of the commercial kitchen hood which derived from this study is 0.48 ∼ 0.55 m/s.

• 설비공학논문집
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• 제24권7호
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• pp.578-584
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• 2012

In this study, the analysis on the distribution of indoor airflow velocity and temperature by using numerical simulation has carried out to make fundamental data for establishing the optimum design of laboratory animal facilities. From the results, it was found that replacement of cage lacks, air supply and exhaust system, supply air temperature, supply air velocity affect to the optimum design of laboratory animal facilities as a important element.

• 한국화재소방학회논문지
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• 제34권4호
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• pp.78-86
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• 2020

본 연구에서는 공동주택 화재 시 부속실 가압 시스템의 방연풍속에 관하여 수치해석을 수행하였다. 수치해석을 통해 댐퍼의 급기량과 방화문에서의 방연풍속의 관계식을 선형적으로 나타내었고 국가화재안전기준인 방연풍속 0.7 m/s를 만족하는 댐퍼의 최소유량을 선정할 수 있었다. 댐퍼의 최소유량을 적용하여 댐퍼의 급기 방향과 설치 높이에 따라 방연속도를 분석하였다. 댐퍼의 급기 방향이 상향인 경우와 댐퍼가 높게 설치되었을 때 댐퍼의 급기 방향이 하향인 경우보다 방화문 상부에서 더 큰 방연풍속을 나타내었고 누출된 연기 농도가 더 낮은 것을 확인할 수 있었다. 따라서 방화문 상부에서 큰 방연풍속을 확보하는 것이 제연에 더 효율적일 것으로 판단된다.

• 한국화재소방학회논문지
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• 제24권6호
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• pp.20-27
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• 2010

배연설비는 연기를 배출한 만큼 공기가 유입되도록 계획된다. 이때 유입공기의 속도가 배연에 어떠한 영향을 미치는지를 FDS를 통하여 분석하였다. 그 결과 화재의 위치로부터 급기구가 가까이 설치된 경우 화재 플럼으로 유입되는 기류속도가 빨라져 상승하는 화재 플럼을 흩트려 버리는 현상이 일어남을 발견하였다. 그로인해 배연성능이 저하되어 연기층의 강하가 더욱 빠르게 촉진되었으며 흐트러진 화재 플럼은 연기층을 교란시켜 가시거리를 더욱 나쁘게 하였다. 따라서 공기유입구의 위치는 화재의 위치로부터 충분히 이격된 위치에 설치하여 화재 플럼으로의 유입공기속도를 낮추도록 하여야 배연효율이 좋아진다는 것을 확인하였다.

• 설비공학논문집
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• 제12권9호
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• pp.810-816
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• 2000

Thermal comfort plays an important role in modern office buildings. Four major factors affecting thermal comfort are air temperature, velocity, humidity and radiation temperature. Distribution of these thermal factors in indoor space depends largely on the air flow which is related to the method of supplying and extracting air. In this study, an experimental analysis on indoor thermal comfort is conducted to study the difference between a ceiling supply cooling system and a floor supply one. The two cooling systems are applied to an office space during summer season and the distributions of temperature, velocity, radiation temperature and PMV are measured. Results show that the floor supply cooling system is superior in terms of thermal comfort and energy saving. Studies need to be done, however, to reduce the vertical temperature difference of a floor supply air conditioning system.

• 드라이브 ㆍ 컨트롤
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• 제13권4호
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• pp.7-13
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• 2016

This paper presents the meter-out and meter-in speed control characteristics of a pneumatic cylinder with relief valve type cushion device. The piston displacement and velocity are measured to investigate high speed driving performance with variation of the pressure setting in relief valve, air supply pressure, load mass, the supply and exhaust flow rate from the cylinder. Also, the internal pressures and temperatures driving pressure and cushion chamber are measured. The piston displacements and velocities of meter-out and meter-in control are compared experimentally determined data. A comparison experimental data meter-out and meter-in control show that a relief valve type cushion device is suitable for high speed pneumatic cylinders. The desired response characteristics of piston displacement and velocity are satisfactory adjust the pressure setting of a relief valve with varying system parameters such as air supply pressure, load mass and controlled flow rate.

• 상하수도학회지
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• 제12권2호
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• pp.76-82
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• 1998

It is necessary to calculate the accurate velocity from the hydraulic model for the reliable prediction of water quality changes in water supply system. To verify the hydraulic analysis of the water supply system, fluoride was used as a tracer to calculate the travel time from the injection point to the sampling points. Results from this field experiment indicate that fluoride can be a good conservative tracer while it showed a little longitudinal dispersion along the pipe lines. And the velocity from the model was verified by these travel times and calibrated by changing the ratio of the unaccountable water. When the ratio of the unaccountable water. When the ratio of the unaccountable water was 20%, the error between the estimation of hydraulic model and the real travel time was minimum.

• 설비공학논문집
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• 제10권5호
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• pp.640-648
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• 1998

A numerical study has been conducted to investigate the effect of inflow supply air temperature and velocity on ventilation effectiveness in an underfloor air conditioning space. A low Reynolds number k-$\varepsilon$ model is implemented to calculate steady state turbulent velocity distributions. A step-down injection method is used to calculate local and room mean ages from transient concentrations based on the concept of the age of air. Results show that there is a significant effect of Archimedes number on ventilation effectiveness especially for cooling conditions. Reynolds number shows relatively minor effect on velocity distribution and ventilation effectiveness especially for isothermal and heating conditions. It can be concluded that underfloor air conditioning system provides good ventilation characteristics for cooling conditions because of temperature stratification in the space.

• 디지털융복합연구
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• 제18권6호
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• pp.109-120
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• 2020

디지털화가 수반되지 않는 공급망은 마케팅, 상품개발, 제조, 물류 및 고객에의 상품 인도라는 여러 단계가 서로 독립적으로 수행되는 과정에 불과하다. 디지털화는 이런 여러 단계 간의 벽을 허물고, 모든 이해관계자 집단에게 투명하고 통합된 네트워크로의 변신을 가능하게 한다. 디지털 공급망관리의 최종 목표는 속도와 가시성이다. 이를 목표 달성을 위해서는 다양한 공급망 테크놀러지가 요구되는데, 여기에는 통합계획수립 및 운영체계, 공급망 애널리틱스, 자율적 물류관리, 스마트 물류센터와 스마트 팩토리 등이 포함된다. 이런 기술들은 예상치 못한 운영조건의 변동사항에 대한 가상 시나리오를 구축하고 이에 대한 솔루션을 제공함으로써 공급망 상의 변동에 대응할 수 있는 역량과 예측력을 강화시킨다. 본 연구에서는 공급망의 디지털화에 대한 여러 연구결과를 제시하고 현실적으로 기술도입 과정에서 제기되는 여러 이슈에 대한 논의를 시도해 보고자 한다. 연구결과에 대한 시사점도 함께 제시한다.

• 한국전산유체공학회:학술대회논문집
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• 한국전산유체공학회 2005년도 추계 학술대회논문집
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• pp.269-273
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• 2005

The on-board system for the air supply to the payload fairing(PLF) of a launch vehicle using both high and low pressure air was designed. The design concept was obtained from the CFD analysis of a Russian interstage air supply system, and a collector was adopted to expand the high pressure air. To verify that the on-board system would work as designed, a simplified axisymmetric computational model was made and a CFD analysis was also performed. It was found that the flow ejected from the hole of the collector expands to the Mach number of 4 and is soon retarded due to the action of viscosity. It was also found that a small gap between the low pressure duct and equipment bay wall can cause large velocity in PLF over the velocity requirement and no gap should be allowed in the design.