• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.3
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• pp.280-286
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• 2004

An experimental study is peformed to examine the heat transfer performance of individual rows of fin-tube heat exchangers. The heat transfer performance is measured using an air-enthalpy type calorimeter. The examined heat exchangers consist of 7mm tube and fin patterns of them are slit and louver types. Equivalent fin spacings are 18 fins per inch(fpi) for all samples, and the number of tube rows are two. In order to confirm that thermal boundary condition on fins of each row are the same, physically separated between two rows as well as connected heat exchangers are used. The frontal air velocity is varied from 0.7 to 2.5㎧. Heat transfer performance for each row is measured. It is observed that the heat transfer coefficient of the second row is smaller than that of the first row at low Reynolds number while larger at high Reynolds number.

• 유체기계공업학회:학술대회논문집
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• 2003.12a
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• pp.238-244
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• 2003

An experimental study was performed to examine the heat transfer performance of individual rows of fin-tube heat exchangers. The heat transfer performance was measured using air-enthalpy type calorimeter. The examined heat exchangers consists of $7{\Phi}$ tube and fin patterns of them are slit and louver types. Equivalent fin spacing are 18 FPI for all samples, and the number of tube rows were 2. In order to confirm that thermal boundary condition on fins of each row are the same, physically separated between two rows as well as connected heat exchangers were used. The frontal air velocity varied from 0.7 to 2.5 m/s. Heat transfer performance for each row are measured. It was observed that the heat transfer coefficient of the 2nd row were smaller than that of the 1st row at low Reynolds number while larger at high Reynolds number.

• KOREAN JOURNAL OF CROP SCIENCE
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• v.29 no.4
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• pp.321-327
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• 1984

Grain yield of rice plants grown in outmost first and second rows in paddy field blocked by 50 cm wide levee was averaged 30 percent more than that in center rows, but yield increased percents in border rows were significantly different between varieties. Average border effect through 3 varieties were recognized only in first and second rows from levee, but most vigorous variety, Hangangchal, showed border effect up to fourth rows from levee. Rice plants grown in border rows had more number of panicles per hill and more number of spikelets per panicle. Total dry matter weight and average leaf area of rice plants in border rows differed with those in center rows from 30 to 60 days after transplanting. Early maturing variety showed the difference between border and center rows quickly concerning to total dry matter weight and leaf area. Rice plants grown in border rows showed higher values of CGR, RGR, NAR, and LAR through the growth duration except 1 or 2 growing periods.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.2
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• pp.149-155
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• 2007

The row-by-row heat transfer characteristics of fin-and-tube heat exchangers were experimentally investigated. Three wavy fin samples having different rows (one, two and three) and one plain fin sample (three row) were tested for $600{\leq}Re_{D}{\leq}4,000$. The heat transfer data were obtained for individual rows, and the corresponding heat transfer coefficients were reduced from the data. Results showed that the heat transfer coefficients were strongly dependent on the tube row. The heat transfer coefficient decreased as the tube row increased. However, the row effect was different depending on the fin shape. For the wavy fin, the row effect significantly decreased as the Reynolds number increased, yielding approximately the same heat transfer coefficients at $Re_{D}{\approx}2,500$. For the plain fin, however, the row effect lasted for the whole Reynolds number range. The increased mixing of bulk flow by wavy channels appears to induce high heat transfer coefficient (accordingly diminishing row effect) at downstream rows. The heat transfer coefficients of individual rows were higher for heat exchangers having larger tube rows.

• Animal Systematics, Evolution and Diversity
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• v.26 no.3
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• pp.307-316
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• 2010

To investigate the Korean ciliate fauna, two oxytrichid ciliates, Laurentiella strenua (Dingfelder, 1962) and Notohymena australis (Foissner and O'Donoghue, 1990) were collected from the Taehwa River in Ulsan, South Korea. These two ciliates are reported for the first time in Korea. Descriptions were based on the observation of live and silver stained specimens. Diagnoses of these species are as follows: Laurentiella strenua: body is approximately $320{\times}170\;{\mu}m$ in size, an inverted triangular shape. Cytoplasmic globules are present in both anterior and posterior margins, transparent and sized $10-15\;{\mu}m$ in live specimens. Adoral zone of membranelles is covering about 50% of body length. Frontoventral-transverse cirri are arranged diagonally into 5 rows. Transverse cirri are arranged almost longitudinally and varied 4-6 in number. Dorsal kineties are 11 rows with multiple fragmentations. Macronuclei are 4-5 in number. Notohymena australis: body is approximately $170{\times}50\;{\mu}m$ in live specimens, slender and long ellipsoidal shape. Yellowish green cortical granules are present as pairs or rows which composed of 3-6 granules. Adoral zone of membranelles is covering about 36% of the body length, composed of 39-50 adoral membranelles. Dorsal kineties is 6 rows. Macronuclei are 2 in number.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2010.06a
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• pp.70-70
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• 2010

Until recently. the study about bypass diode has been limited to theoretical study. but, in this paper, We study on the relationship between structure of PV module and Bypassing point by simulation software(Pspice). We expected the design on the PV module has an effect on bypassing point. So, we designated the two kind of experiment with PV modules. One of the experiment is on the relationship between the number of rows and Bypassing point on the PV modules, the other experiment is on the relationship between the number of groups(two columns) on the PV modules.(around 50Wp, 100Wp, 150Wp, 200WP) As the result, the more increase the number of rows, bypassing point is faster. And the more increase the number of groups in more than 3 groups, bypassing point is faster more than case of increasing the rows.

• Journal of Species Research
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• v.1 no.1
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• pp.78-86
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• 2012

Three ciliate species of genus Cyrtohymena, C. australis Foissner, 1995, C. citrina (Berger & Foissner, 1987) and C. muscorum (Kahl, 1932) new to Korea, were collected from semi-terrestrial habitats. The description was based on the observation of live and silver stained specimens. Diagnostic characteristics of these species are as follows. C. autralis: size about $275{\times}100{\mu}m$ in live specimens. Cortical granules yellowish. 18-31 right and 31-40 left marginal cirri in number. Dorsal kineties eight rows. C. citrina: size about $180{\times}50{\mu}m$ in live specimens. Cortical granules yellowish. 26-32 right and 23-27 left marginal cirri in number. Dorsal kineties five to six rows. C. muscorum: size about $180{\times}60{\mu}m$ in live specimens. Cortical granules reddish. 31-34 right and 33-36 left marginal cirri in number. Dorsal kineties six rows. Three species of Cyrtohymena have been added to Korean ciliate fauna from this study. Including previous one species of C. quadrinucleata, four species of this genus in total have been recorded so far in this country.

• Solar Energy
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• v.9 no.2
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• pp.31-41
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• 1989

The purpose of this research is to study the utility of prediction program like a F.E.M. analysis for energy recovery of heat exchanger with heat pipe which uses arbitrary groove wick. The program is based on the utility by the experimental and applytical method of the single heat pipe. It is also expanded and applied in the prediction program of the heat exchanger. The results are as follows; 1) The effective thermal conductivity of the groove wick with arbitrary shape is counted by the thermal resistance change. 2) The more the number of rows, the more the effect energy recovery changing by the number of rows, the bigger the free velocity, the smaller the effect of energy recovery. 3) The effect of energy recovery increases according to the value of the rate of mass flow (Me/Mc) and also number of rows. 4) The comparison between calculated and data shows good agreement within 2.5% error, therefore the F.E.M. analysis of the study is useful to predict the performance of heat pipe-heat exchanger.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.10 no.5
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• pp.589-599
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• 1998

Air side heat transfer and pressure drop for fin-tube heat exchanger with wave and wave-slit fins were measured for various fin spacings and number of tube rows. Outer diameter of the tube including fin collar is 10.07mm, and experiments were done with dry surface condition. Longitudinal and transverse tube spacings of the heat exchangers are 21.65mm and 25mm respectively, and wave depth of the wave fin is 2mm. Experiments were conducted for 1, 2 and 3 rows and 3 different fin spacings, 1.3, 1.5 and 1.7mm. An attempt was made to demonstrate advantage of the enhanced fins over the plane fin by introducing the concept of fan power, Effect of the number of tube rows on heat transfer was discussed in connection with general mechanisms of heat transfer enhancement for fin-tube heat exchanger. Also the effect of hydrophilic coating was investigated. Lastly, correlations for Colburn j-factor and friction factor were developed.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.22 no.11
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• pp.1555-1563
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• 1998

Heat transfer and pressure drop for ${\phi}10.07$ dry surface fin-tube heat exchanger with wave and wave-slit fins were measured for different fin spacings and number of tube rows. Longitudinal and transverse tube spacings of the heat exchangers are 21.65mm and 25mm respectively, and wave depth of wave fin is 1.5mm. The experiments were performed for 4 different fin spacings, 1.3, 1.5, 1.7 and 2.0mm, and the number of tube rows were 1,2 and 3 rows. The present results were compared with the previous results for the wave depth of 2mm. Also hydrophilic coated and bare fins were tested. Correlations for Colburn j-factor and friction factor were developed.