• Journal of Advanced Marine Engineering and Technology
• /
• v.25 no.6
• /
• pp.1220-1227
• /
• 2001

The condensation pressure drop fur refrigerant R-22 flowing in the plate and shell heat exchanger were investigated experimentally in this study. Two vertical counterflow channels were formed in the exchanger by three plates of commercial geometry with a corrugated trapezoid shape of a chevron angel of $45^{\circ}$. The condensing R-22 flowing down in one channel exchanges heat with the cold water flowing up in the other channel. The effects of the mean vapor quality, mass flux, average imposed heat flux and system pressure of R-22 on the pressure drop were explored in detail. The quality change of R-22 between the inlet and outlet of the refrigerant channel ranges from 0.03 to 0.05. The present data showed that pressure drop increases with the vapor quality. At a higher mass flux, pressure drop is higher for the entire range of the vapor quality. Also, a rise in the average imposed heat flux causes an slight increase in the Pressure drop. Finally, at a higher system pressure the pressure drop is found to be slightly lower. Correlation is also provided for the measured pressure drops in terms of the friction factor.

• Transactions of the Korean Society of Mechanical Engineers B
• /
• v.33 no.7
• /
• pp.527-534
• /
• 2009

Flame stabilization characteristics were experimentally investigated in a fuel-air cross flowing mixing layer. A combustor consists of a narrow channel of air steam and a cross flowing fuel. Depending on the flow rates of methane and air, flame can be stabilized in two modes. First is an attached flame which is formulated at the backward step where the methane and air streams meet. Second is a lifted-flame which is formulated within the mixing layer far down steam from backward step. The heights and flame widths of the lifted flames were measured. Flame shapes of the lifted flames were similar to an ordinary edge flame or a tribrachial flame, and their behavior could be explained with the theories of an edge flame. With the increase of the mixing time between fuel and air, the fuel concentration gradient decreases and the flame propagation velocity increases. Thus the flame is stabilized where the flow velocity is matched to the flame propagation velocity in spite of a significant disturbance in the fuel mixing and heat loss within the channel. This study provides many experimental results for a higher fuel concentration gradient, and it can also be helpful for the development and application of a smaller combustor.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.18 no.5
• /
• pp.1275-1284
• /
• 2004

This paper discuss the acupoints and flowing of channel. The Acupoints issued from the Foot Taiyin channel's energy are seventy three. The acupoints issued from the Foot Shaoyang channel's energy are sixty two. The acupoints issued from the Foot Yangming channel's energy are sixty eight. The acupoints issued from the Hand Taiyang channel's energy are thirty six. The acupoints issued from the Hand Yangming channel's energy are twenty two. The acupoints issued from the Hand Shaoyang channel's energy are thirty two. The acupoints issued from the Du channel's energy are twenty eight. The acupoints issued from the Ren channel's energy are twenty eight. The acupoints issued from the Chong channel's energy are twenty two. The acupoints issued from the Foot Shaoyin channel are the Lianquan points of kidney channel on each side under the tongue. The total points above amount of three hundred and sixty five. Urinary Bladder Channel of Foot-Taiyang: The number of acupoints is 67. Gall Bladder Channel of Foot-Shaoyang: The number of acupoints is 44. Stomach Channel of Foot-Yangming: The number of acupoints is 45.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.10 no.1
• /
• pp.86-95
• /
• 1986

A study on film water flow on steep open channel has been seldom found up to date. Therefore, this paper dealed with the depth variation of film thickness of water (city supply normal water) flowing on steep open channel. For this purpose, Experimental apparatus (made of a normal glass with 160cm of length and 15cm of width) was made and the depths of the water flowing on the channel were measured experimentally, changing the channel slope angle from 30 to 80 degree (5 steps) and the flow rate from 0.25 to 10CPM (11 steps). The results obtained, some characteristics of the film flow on the channel are as follows. (1) When thin film water flowed on steep open channel, the depths of flow tended to increase after decreasing and was kept nearly constant in its downstream in case of laminar and transitional flow region. The turining point of the depths of flow from decrease to increase tended to move downward with the increase of Reynolds number. In turbulent flow region, the depths of flow showed reapid decrease in its upper stream, gradual decrease in its midstream and were kept nearly constant in its downstream. (2) While the differences between the depths of flow along the channel slope got small in its upper stream and got large in its downstream in case of laminar flow region, they got very large in its upper stream and were kept nearly constant in its downstream in case of transitional and turbulent flow region. And the move flow rate increases, the more the differences between the depths of flow along the channel slope got large in its upper stream.

• Korean Management Science Review
• /
• v.26 no.1
• /
• pp.161-169
• /
• 2009

A traffic analysis on the Internet has an advantage for obtaining the characteristics of transferred packets. There were many studies to understand the characteristics of the Internet traffic with mathematical statistical approach. The approach of this study is different from previous studies. We first introduced a virtual network concept to present the Internet as a simplified mathematical model. It also represents each traffic flowing on the Internet as a parallel Gaussian channel on the virtual network. We suggest the optimal capacity of each parallel Gaussian channel using some related studies on the Gaussian channel model.

• Journal of The Geomorphological Association of Korea
• /
• v.28 no.3
• /
• pp.1-11
• /
• 2021

The drainage area of the Miho stream is composed of granitic basins, gneissic and sedimentary mountains. 80 percent of the Miho stream flows through the Jincheon basin and the Cheongju inner-plain within the Daebo granite belt. Because the deep weathering of granitic hills provides a large amount of sands to the streams, there are wide floodplains with thick alluvium developed in the basin and plain. The thickness of the alluvium is 5~10m and the width of the floodplains is 2~2.5km. In the basin outlet area where a stream passes through the mountain canyon, wide floodplains and deep alluvium are developed in other riverside. The Miho stream is a sand-gravel channel flowing through the Cheongju inner-plain with wide floodplains and deep alluvium formed by deep weathering of granite.

• Journal of Korean Medical classics
• /
• v.12 no.2
• /
• pp.282-292
• /
• 1999

In oriental medicine Acupuncture treatment is one of the most valuable therapy. Through the acupuncture humen have been healed many diseaes with his own natural therapic power, without medicine or surgery ect. But there have not formed a clear definition on the supplement & eradication(補瀉). I recognised the difference between the original meaning of Young-su(迎隨) mentioned in $\ll$Whang-Je-Nae-Kyung(黃帝內經)$\gg$ and Young-su-Bo-Sa(迎隨補瀉) that are recently used. The results were summerized as follow; 1. In the $\ll$Whang-Je-Nae-Gyung$\gg$, when they give medical teatment, they have totally used all methods of the supplement & eradication(補瀉). Therefore as now divided into respiration, speed, rotation and close-open supplement & eradication(補瀉) have many problomes. And Young-su(迎隨) did not mean the treatement of supplement and eradication which go with or against the flowing of channel energy(經氣). Young-su(迎隨) is not a simple technique of treatment, but is the totall principle of the supplement and eradication. 2. The direction of channel energy(經氣) connected with the O-su point (五輸穴) is from extremities to the trunk of body, therefore the direction of supplement is to the trunk of body and the direction of eradication is to extermities. 3. In the case of using the treatment which go with or against the flowing of channel energy(經氣), in oder to avoid the confusion of term, it must be defined another term. 4. It is necessary that we must define the procedure of supplement & eradication, and the objective indication that ascertain whether the doctor's purposes are really obtained.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2002.11a
• /
• pp.168-187
• /
• 2002

Scour is the physical or chemical attack of flowing water which excavates and carries away material from stream beds and banks. Especially, hydraulic structures such as bridge piers and abutments placed in the channel causes the changes of the flow pattern like acceleration, the formation of vortices, and scour around the structures. Channel scour, especially bridge pier scour is the leading cause of bridge failures. It is very important to apply appropriate methods for both of scour analysis and protection. In this paper, several methods world-widely used for bridge scour analysis and protection are introduced and compared.

• Proceedings of the Optical Society of Korea Conference
• /
• 2009.10a
• /
• pp.318-319
• /
• 2009

• Proceedings of the KSME Conference
• /
• 2007.05b
• /
• pp.2811-2816
• /
• 2007

We conducted a numerical study of AC-electroosmotic (alternating current) effect on the fluid flow and mixing in a 3-D microchannel. The microchannel used as an efficient micro-mixer is composed of a channel and a series of pairs of electrodes attached in zigzag pattern on the bottom wall. The AC electric field is applied to the electrodes so that a steady flow current takes place around the electrodes. This current is flowing across the channel and thus contributing to the mixing of the fluid within the channel. We performed numerical simulations by using a commercial code to obtain a steady flow field. This steady flow is then used in evaluation of the mixing performance via the concept of mixing index. It was found that good combination of two kinds of electrode, which gave us a good mixing, is not simple harmonic. And when the length ratio of these two kinds of electrode is 2:1, we can get the best mixing effect.