• 한국가구학회지
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• 제19권1호
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• pp.91-96
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• 2008

This paper investigates the penetration of essential oil into radial and longitudinal directions of Castanea crenata. Present study was performed to know the essential oil penetration depth in radial and longitudinal direction of Castanea crenata. Essential oil penetration depth was found higher in longitudinal direction than in radial direction and it was about 53 times high at 15.0 second of penetration. In early wood, fiber conducted oil more than that of large vessel. In heartwood, fiber had played an important role for the conduction of oil. But in sapwood, small vessel conducted oil deeper than wood fiber, which was also significantly different from large. On the other hand, large vessel in heartwood had statistically lower penetration depth than that of fiber and small vessel. At the beginning of penetration the speed was high and gradually decreased in course of time.

• 한국가구학회지
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• 제18권3호
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• pp.243-247
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• 2007

An experiment was conducted to observe the safranine penetration depth in radial directions of Populus tomentiglandulosa. Radial penetration was considered from bark to pith. In radial direction, ray parenchyma and intercellular space were considered for the measurement of safranine penetration depth. It was found that sapwood conducted safranine 24.23% higher in radial direction compared with heartwood. Intercellular space conducted safranine 39.27% higher depth compared with ray parenchyma and the penetration depth was 39.41% higher in sapwood compared to heartwood. During safranine penetration, it formed a curvature in the lumen of ray parenchyma. Initially safranine penetration was found high and decreased gradually.

• 한국가구학회지
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• 제18권4호
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• pp.282-286
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• 2007

An experiment was conducted to compare the 1% safranine solution flow depth in radial and longitudinal direction of Prunus sargentii. Longitudinal flow of safranine solution was found higher than radial flow. Body ray parenchyma was found more permeable than marginal ray parenchyma and it was about 1.3 times higher. Intercellular space conducted safranine solution more than ray parenchyma. Vessel was found to be the main avenue for liquid conduction in longitudinal direction. Different anatomical features of ray, vessel and fiber affected the penetration depth of safranine solution. Moreover initial penetration depth was found to be high and thereafter decreased gradually.

• 한국가구학회지
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• 제18권2호
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• pp.100-105
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• 2007

In this report, we describe the anatomical features of Gmelina arborea Roxb. belong to the genera of Verbenaceae native to Bangladesh and safranine penetration depth in radial and longitudinal directions. The wood of this species was characterized mostly by distinct growth ring boundaries, diffuse-porous, simple perforations, alternate non-vestured intervessel pits, and relatively short vessel elements and medium fibers. Thin to thick walled septate fibers with simple to minutely bordered pits are confined to the radial walls. Tyloses are common. They are paratracheal axial parenchyma vascicnetric and confluent. Rays not higher than 1milimeter are found, and larger rays commonly 4 to 5 seriate are dominantly present, as are multi seriate rays composed of a procumbent ray with 1 row of square or upright cells. Acicular crystals are present in ray cells. Another experiment was taken under consideration to observe the liquid penetration depth in longitudinal and radial directions using safranine. It was found that safranine penetrated easily in longitudinal direction and sapwood was more permeable than heartwood.

• 한국자동차공학회논문집
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• 제9권6호
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• pp.16-23
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• 2001

Spray dispersion in high pressure diesel engines have been simulated experimentally with a special emphasis on the effect of swirl by using a liquid injection technique. A constant volume chamber was designed to be rotatable in order to generate a continuous swirl and to have the flow field closely resembling a solid body rotation. Emulsified fuel was injected into the chamber and the developing process of fuel sprays was visualized. The effect of swirl on the spray dispersion was quantified by calculating non-dimensionalized dispersion area according to the spray tip penetration length. The results show that the effect of swirl on the spray dispersion is different between short and long spray penetrations. For short range of spray tip penetration, the effect of swirl on spray dispersion is quite small. However, as the spray tip is penetrated into longer distance in spray chamber, the effect of swirl on spray dispersion becomes larger. These results can be used as a basic data for designing combustion chamber and injection system of direct injection diesel engine.

• 한국분무공학회지
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• 제12권3호
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• pp.154-159
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• 2007

Spray tip penetration and spray angle for one main injection were measured at the atmospheric condition with the fuel injection pressure of 270 bar and 540 bar. It investigates an effect of different nozzle hole geometry of conventional cylindrical one and those of elliptical ones. Injection period represented by injector pulse drive was fixed at 1ms. From the result of this study, it is shown that spray tip penetration becomes shorter and spray angle becomes wider with the elliptical nozzle hole geometry due to fast break-up of a fuel liquid column.

• 한국항공우주학회지
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• 제45권6호
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• pp.447-454
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• 2017

난류 유동장으로 분사되는 두가지 형태의 액체 제트 (수평분사는 디젤연료와 수직분사는 물)의 액주 분열과 미립화 현상에 관한 이상(Two-phase) 유동에 대해 3차원 LES 수치해석을 수행하였다. 기체상태의 공기 유동은 오일러리안 해법을 사용하고, 액체 제트의 액적 추적은 라그랑지안 해법을 사용하여 기체-액체간 이상유동 해석을 수행하였다. 두 종류의 확률론적 분열 모델(Stochastic breakup model)을 사용하여 액적 분열을 모사하였으며, 액체제트의 침투깊이와 액적 분포(Sauter Mean Diameter)를 실험결과와 비교하여 미세하게 분열되는 액체 제트의 분열 현상에 대해 확률론적 분열 모델링의 적합성을 제시하였다.

• 한국자동차공학회논문집
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• 제16권2호
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• pp.87-92
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• 2008

The breakup processes and spray plume characteristics of liquid jets injected in subsonic air cross-flows were experimentally studied. The behaviors of column, penetration, breakup of plain liquid jet and droplet sizes, velocities have been studied in non-swirling cross-flow of air. Nozzle has a 1.0 mm diameter and Lid ratio=5. Experimental results indicate that the breakup point is delayed by increasing air momentum, the penetration decreases by increasing Weber number and the split angle is increased by increasing air velocity or decreasing injection velocity. SMD increases according as increasing height or decreases in accordance with increasing air velocity. This phenomenon is related to the momentum exchange between column waves and cross-flow stream. Droplet vector velocities were varied from 11.5 to 33 m/s. A higher-velocity region can be identified in down edge region at Z/d=40, 70 and 100. Lower-velocity region were observed on bottom position of the spray plume.

• 한국가구학회지
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• 제26권2호
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• pp.179-185
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• 2015

A study was carried out to observe the 1% aqueous safranine solution flow speed in longitudinal and radial directions of softwood G. biloba, ring-porous wood A. altissima, and diffuse- porouswood D. kaki. In radial direction, ray cells and in longitudinal direction tracheids, vessel and wood fiber were considered for the measurement of liquid penetration speed at less than 12% moisture contents (MC). The length, lumen diameter, pit diameter, end wall pit diameter and the numbers of end wall pits determined for the flow rate. The liquid flow in the those cells was captured via video and the capillary flow rate in the ones were measured. Vessel in hardwood species and tracheids in softwood was found to facilitate prime role in longitudinal penetration. Radial flow speed was found highest in ray parenchyma of G. biloba. Anatomical features like the length and diameter, end-wall pit numbers of ray parenchyma were found also responsible fluid flow differences. On the other hand, vessel and fiber structure affected the longitudinal flow of liquids. Therefore, the average liquid penetration depth in longitudinal tracheids of G. biloba was found the highest among all cells considered in D. kaki and A. altissima.

• Journal of Mechanical Science and Technology
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• 제17권12호
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• pp.2019-2026
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• 2003

Spray and combustion characteristics of a dump-type ram-combustor equipped with a V-gutter flame holder were experimentally investigated. Spray penetrations with a change in airstream velocity, air stream temperature, and dynamic pressure ratio were measured to clarify the spray characteristics of a liquid jet injected into the subsonic vitiated airstream, which maintains a highly uniform velocity and temperature. An empirical equation was modified from Inamura's equation to compensate for experimental conditions. In the case of insufficient penetration, the flame in the ram-combustor was unstable, and vice versus in the case of sufficient penetration. When the flame holder was not equipped, the temperature at the center of the ram-combustor had a tendency to decrease due to the low penetration and insufficient mixing. Therefore, the temperature distribution was slanted to the low wall of the ram-combustor. These trends gradually disappeared as the length of the combustor became longer and the flame holder was equipped. Combustion efficiency increased when the length of the combustor was long and the flame holder was equipped. Especially, the effect of the flame holder was more dominant than that of the combustor length in light of combustion efficiency.