• 한국전산유체공학회:학술대회논문집
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• 1999.11a
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• pp.139-144
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• 1999

There have been many studies for heat transfer enhancement. Particularly, the study of flow in heat exchangers which have fin device has been main theme in heat transfer area. Practically, the circular tube which has internal fins is widely used for developing heat transfer rate. In this study, flow and heat transfer analysis of the circular tube with fins are investigated. The height and the number of fins are arbitrary. The flow field is assumed to be laminar. The conformal mapping is used for analytic solution of the laminar flow field. Discretization of governing equation, namely, FDM was used for numerical analysis. The velocity field, flow rate and shear stress are calculated for some numbers of fins in circular tube and for some heights of fin. Temperature fields are plotted along the tube length. It can be shown that the numerical solution agrees with the analytical solution.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.10a
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• pp.804-807
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• 2002

In general, the reinforcement of a structure is performed with cylinders. In this study, it is attempted to analyze the circular reinforcement with fins. And the maximum stress and deflection is investigated fur the circular reinforcement between two plates. The shape of models are : one which has only circular reinforcements of different diameters and one which has circular reinforcements with fins and one which has fin of same length and circular cylinders of different diameters. And in each model, there are two kinds; one is with upper and lower plates and the other with none. The results shows that the maximum stress is less in the model of circular reinforcement with fins than that in the model without fins. And the maximum stress of a model without upper and lower plate is less than that of a model with plates.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.51 no.5
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• pp.595-599
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• 2018

One specimen (181.0 cm; TL, total length) of Echinorhinus cookei was collected from Busan, Korea in 2014 using gill net. Echinorhinus cookei was characterized by having no anal fin, no spine at dorsal fin and numerous small dermal denticles at the placoid scale. This species is very similar to the congeneric species, E. brucus, but differed in the shape of placoid scale (star in E. cookei vs. round in E. brucus) and distribution of placoid scale (separated in E. cookei vs. slightly overlapped in E. brucus). We adopted the Korean name, Ga-si-bi-neul-sang-eo, for E. cookei, after Kim and Ryu (2017).

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.24 no.3
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• pp.265-270
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• 2012

A finned tube type heat exchange module has been proposed for a multi-burner water tube boiler. Fin density and length increase in streamwise direction to equalize the evaporation for each module, which makes it difficult to apply conventional bulk design procedure. The design program has been improved by updating data for every row of tubes along the flow. A numerical simulation has been also conducted to evaluate the effect of inlet conditions and validated with experiment. The heat transfer of the first row has been underpredicted by the conventional Zhukauskas correlation, since the acceleration of the flow due to the blockage is not fully inflected. The fin tip temperature is also underpredicted by Bessel solution, because of the interaction with neighboring fins.

• Journal of the Korean Society of Safety
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• v.16 no.4
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• pp.22-28
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• 2001

Heat transfer and pressure distribution for heat exchanger type of domestic gas boiler are different from shape, pitch, thickness of fin and array of pipe respectively. In order to measure the pressure distribution across the heat exchanger, a suction type wind tunnel was constructed and velocity distribution was measured for pilot tube(4 point) of rack type. The experiments were performed for 5 different air flow mass, rpm=3,6,9,12,15 and transverse axis of heat exchanger(x-length) is 5cm respectively. Results showed that above 9.5m/s, pressure distribution dispersion for wet type of heat exchanger is on the increase and above 5.5m/s, pressure distribution dispersion for dry type of heat exchanger is on the increase. Also, pressure distribution dispersion by comparing two different types heat exchanger, dry type of heat exchanger showed a higher augmentation than wet type of heat exchanger.

• Proceedings of the KSME Conference
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• 2004.04a
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• pp.2105-2110
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• 2004

Plate-fin type recuperators for the gas turbine/fuel cell hybrid power generating system were designed using commercial design software, MUSE. Heat transfer efficiency and total pressure drop in the recuperator were calculated to confirm required recuperator performance. Both counter flow and cross flow type plate-fin recuperators were designed. Results show that the counter flow type has higher efficiency and short core length, but the cross flow type is simpler to construct because the cross flow type does not need additional distributors. Two or three headers for the each recuperator core will be designed and tested to evaluate best header design. The designed recuperators and headers which will be designed later will be constructed, tested, and used in gas turbine/fuel cell hybrid power generating system.

• Korean Journal of Ichthyology
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• v.25 no.1
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• pp.42-45
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• 2013

Single specimen (68 mm TL) of the Shiho's seahorse Hippocampus sindonis collected from Geomun Island was described as a first record from Korea. The species is characterized by having 15 dorsal fin-rays, 14 pectoral fin-rays, snout length 2.8 in HL, trunk rings 10, and tail rings 37. A new Korean name, "Sin-do-hae-ma" is proposed.

• Journal of the Korea Institute of Military Science and Technology
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• v.22 no.5
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• pp.625-636
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• 2019

Recently, research on projectiles with wings for precision guidance is actively underway. In this study, we analyzed how the tail fins attached to the projectile affect the base drag. Aerodynamic analysis was performed with RANS(Reynolds Averaged Navier-Stokes) equations using FLUENT, a commercial CFD(Computational Fluid Dynamics) code. Through the aerodynamic analysis, the base drag characteristics of the projectile by parameters (number, length, thickness, position, shape of tail fin) were investigated. The results of this study are expected to be applicable to aerodynamic design of tail fins mounted on projectiles.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.55 no.5
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• pp.736-741
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• 2022

A single specimen (91.5 cm standard length) of the salmonid species, Oncorhynchus tshawytscha (Walbaum, 1792) was collected on April 19, 2022 in Sokcho-si, Gangwon-do, Korea. O. tshawytscha has the following morphological characteristics: base of lower jaw teeth is black, black spots are scattered on the dorsal section of body, and the edge of caudal fin is black. Although the species is morphologically similar to Oncorhynchus kisutch, O. tshawytscha differs from it in having black spots on the caudal fin. Molecular analysis results based on mitochondrial cytochrome c oxidase subunit I (COI) sequences showed that our specimen perfectly matched with the COI sequences of O. tshawytscha registered at the NCBI. Therefore, we suggest the new Korean name 'Wang-yeon-eo' for O. tshawytscha.

• Korean Journal of Ichthyology
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• v.29 no.3
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• pp.224-228
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• 2017

Two specimens of Ruvettus pretiosus (227.0 and 238.3 mm in standard length), belonging to the family Gempylidae, was firstly collected by using a gill net from the eastern coastal waters of Jejudo Island, Korea in November 2013. This species is characterized by having the following morphological traits: XV, 17~19+2 dorsal fin rays; II, 15~16+2 anal fin rays; belly keeled between pelvic fin and anus; body covered with cycloid scales, interspaced with rows of sharp bony tubercles. R. pretiosus can be easily distinguished from three Korean Snake mackerels (Thyrsitoides marleyi, Rexea prometheoides and Gempylus serpens) by having belly keeled between pelvic fin and anus, and cycloid scales covered the body and interspaced with rows of sharp bony tubercles. Based on morphological and molecular approaches, the specimens were identified as R. pretiosus. We propose new Korean names, "Gi-reum-chi-sok" and "Gi-reum-chi" for the genus and species, respectively.