• Solar Energy
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• v.18 no.3
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• pp.217-228
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• 1998

The purpose of this research is to investigate the characteristics of static and total pressure distribution in the upward free water jet system impinged on a downward flat plate. The rectangular nozzle was used and its contraction and aspect ratio was five and about seven respectively. Experimental conditions considered were jet velocity, distance between nozzle and flat plate, height of supplementary water. It was founded that pressure distribution on the flat plate had the Gaussian curve when the pressure at stagnation point and impinging half width were chosen as the scaling parameters. The maximum pressure was shown at the stagnation point. The central impingement velocity decreased with the increment of distance between nozzle and flat plate, and its slop of decay was similar to that of chracteristics decay region in the three-dimensional free jet.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.15 no.3
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• pp.234-243
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• 1986

이번 호서부터는 주로 충돌수분류계의 유동특성 및 열전달특성에 대하여 대표적인 실험결과를 문헌들을 인용하여 소개하기로 한다. 우선 이 호에서는 그 유동특성에 대하여 설명한다.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.15 no.1
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• pp.58-61
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• 1986

• Proceedings of KOSOMES biannual meeting
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• 2009.06a
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• pp.87-88
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• 2009

In evaporating distillation plant velocity characteristic of fluid to flow in a evaporator have great influence on flash phenomenon. In This experimental study about impinging water jet region having the inflow of wall jet flow and effect of baffle height to flow velocity in after baffle region, making a application by PIV.

• Solar Energy
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• v.15 no.1
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• pp.53-71
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• 1995

Experiments have been conducted on a planar, free surface jet of water to investigate the effects of aspect ratios(AR=6.67, 15, 26.67), average nozzle velocity($V_0=3.3m/s{\sim}78m/s$) and nozzle-to-plate spacings($Z/W=6{\sim}40$) on the characteristics of heat transfer, when 3 rectangular waterjets impinging on a flat plate which has the uniform heat flux. the scondary peaks which produced by circular jets also produced by rectangular water jets. The position of the scondary peaks depends upon the aspect ratio of nozzle. The heat transfer coefficient was subjected to the influence of aspect ratio. The heat transfer correlations and best position of nozzles which produced maximum heat transfer coefficient at stagnation point are provided.

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.15 no.2
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• pp.155-162
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• 1986

• The Magazine of the Society of Air-Conditioning and Refrigerating Engineers of Korea
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• v.15 no.4
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• pp.323-335
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• 1986

• Transactions of the Korean Society of Mechanical Engineers
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• v.16 no.6
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• pp.1150-1155
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• 1992

The cooling characteristics of a hot steel plate by a laminar impinging water bar were investigated experimentally. The dynamic parameters investigated were nozzle height L between nozzle and the hot plate, flow rate Q, and initial cooling temperature. Because the boiling phenomena on a hot steel plate are unsteady and change discontinuously, it is difficult to analyze the cooling characteristics directly. In this study the cooling efficiency was estimated by using the temperature decay rates and expansion speed of the water cooling zone. Temperature in the water cooling zone decreased rapidly and the radius of the water cooling zone expanded nearly in proportion to square root of the cooling time. With increasing initial temperature of a hot steel plate, the cooling efficiency became descendent. The cooling curve in the case of L/D = 30 showed the largest temperature decay rate and excellent cooling performance.

• Solar Energy
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• v.15 no.2
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• pp.47-64
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• 1995

An experimental investigation is carried out to see the local heat transfer characteristics of a rotating heated flat plate surface with constant heat flux when a normal water jet is impinging on this surface. The effects of jet Reynolds number, rotating Reynolds number are investigated while the distance between the nozzle and the flat plate is set fixed. As a result, correlations to relate the local Nusselt number to the local rotational Reynolds number, jet Prandtl number and the dimensionless radial position are presented.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.34 no.2
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• pp.203-212
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• 2010

Water spray cooling has been widely used in a variety of industrial applications. The present study concentrated on quantitative measurements of the heat flux and heat transfer coefficient by water spray as it impinges on the rough surface of a hot steel plate at $900^{\circ}C$. A novel experimental technique was developed for a hightemperature heat flux gauge with a test block, cartridge heaters, and thermocouples that was used to measure the surface heat flux information on the hot steel plate for local heat flux measurements. The roles of the surface roughness on heat transfer are presented in this paper for well-characterized four rough surfaces with average rms roughness heights of $40-80{\mu}M$. The results show that the local heat transfer for rough surfaces is higher than that for a smooth surface. Heat transfer can be significantly increased by the presence of surface roughness elements, which can disrupt the thin thermal boundary layer. In addition, the heat transfer enhancement mechanism on a rough surface can be investigated by a different boiling regime.