• Journal of Korean Society of Steel Construction
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• v.13 no.6
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• pp.609-619
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• 2001

It is almost impossible to evaluate the ultimate strength theoretically, because the behavior of Gusset-Tube connection stiffened with rib-plate is considerably complicate. Therefore in this study a finite element model of gusset-tube connection stiffened with rib-plate was established. The validity of finite element analysis was examined through comparing with previous experimental result and the behavior and strength of the connection was examined. From the parametric study considering lateral force ratio, eccentricity, gusset length based on finite element model, the stiffened effect was estimated and stiffening method was proposed.

• Journal of Korean Association for Spatial Structures
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• v.12 no.4
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• pp.81-90
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• 2012

The concrete-filled tube (CFT) column has the excellent structural performance. But it is difficult to connect with column and beam because of closed section. Its Solution, 2 members of ㄷchennel in which Internal diaphragm is installed were welded beforehand and the method of making Rectangular Steel Tube was proposed. According to upside and downside junction shape, Internal diaphragm suggested as symmetric specimen and asymmetric specimen. The upper and lower diaphragm of the Symmetric specimen used the same horizontal and The upper diaphragm of the Asymmetric specimen used the horizontal plate and the lower diaphragm used the vertically plate. In this research, 4 T-shape column to beam steps connections were tested with cyclic loading experiment in order to evaluate the structural capability of the offered connection. Symmetric specimens be a failure in 0.03rad from beam flange. And Asymmetric specimens be a failure in 0.05rad from column interface. The comparison results of All specimens shown similar to energy absorption capacity in 0.02rad.

• Journal of Internet of Things and Convergence
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• v.8 no.1
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• pp.23-29
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• 2022

The product to be developed in this study is a heat recovery device which generates steam or hot water at high temperature and high pressure by heating water using exhaust gas from diesel engine, gas engine, gas turbine, etc. as an exhaust gas boiler off heat boiler(EGB) type for ship and power generation. The steam vapor or the created warm water is used as the power source required for the steerage heating and hot water facility or the HFO heating of the ship, and the turbine drive. The principle of waste heat boilers serves to heat water as high temperature exhaust gas with heat pass through the tube of the boiler. The heated water is a structure that is sent to a cabin or turbine device in the form of steam. In this study, the objective of this study is to maximize the efficiency by increasing the heat transfer surface by replacing the tube which is the heat transfer part of EGB with the plate tube.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.28 no.2
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• pp.135-145
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• 2004

An experimental study is conducted to investigate the flow and heat transfer characteristics of a multi-tube inserted impinging jet. Four different multi-tube devices are tested for various nozzle-to-plate distance. Flow visualization by smoke-wire method and velocity measurements using a hot-wire anemometer are applied to analyze the flow characteristics of the multi-tube insert impinging jet. The local heat transfer coefficients of the multi-tube inserted impinging jet on the impingement surface are measured and the results are compared to those of the conventional jet. In multi-tube inserted system the multi-tube length plays an important role in the flow and heat transfer characteristics of the jet flow. With multi-tube insert of I3d4 and I6d4 which has relatively longer tube length than the multi-tube-exit of I3d1 and I6d1, the flow maintains its increased velocity far downstream due to interaction between adjacent flows. For the small H/D of 4, the local heat transfer coefficients of multi-tube inserted impinging jet are much higher than those of the conventional jet because the flow has higher velocity and turbulent intensity by the use of the multi-tube device. At large gap distance of H/D=12, also higher heat transfer rates are obtained by installing multi-tube insert except multi-tube insert of I3d1.

• Journal of the Korean Society for Nondestructive Testing
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• v.11 no.1
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• pp.7-12
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• 1991

The multi-frequency eddy current technique has been used for evaluation of various type of defects in tubings. However, this technique is not sufficient to detect and evaluate the defect in tubings if the defect is located in the geometrically complicated area(e. g. tube support plate, anti-vibration bar, tubesheet area) and mixing residue signal is significant to the defect signal. In order to improve the reliability of the multi-frequency eddy current technique, the effect of the interaction of mixing residue after frequency mixing with a function of distances between the defect and the tube support plate boundary has been analyzed theoretically. The experimental results have been discussed with the theoretical developments. The calculation shows the interaction between the two neighboring signal sources could be significant within the range of approximately 1.0mm with the experimental condition.

• 한국태양에너지학회:학술대회논문집
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• 2008.04a
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• pp.215-220
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• 2008

This study shows the results on thermal performance test with domestic solar collector for low-temperature applications using KS, then reveals the efficiency difference between KS and EN standard. Using the test results, this study presents the status of thermal performance with domestic solar collector including flat-plate, single evacuated, and double evacuated (with mirror or U-tube) solar collector.

• International Journal of High-Rise Buildings
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• v.1 no.1
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• pp.21-28
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• 2012

Diagrid system has been in the spotlight for its superiority in terms of the resistance to lateral force when applied to skyscrapers. In diagrid system, most of columns can be eliminated because vertical loads (gravity loads) and horizontal loads (lateral loads) are delivered simultaneously thanks to the triangular shape of diagrid. However, lack of studies on connection shape and node connection details makes it hard to employ the system to the buildings. In this study, the structural safety of the node connections in circular steel tube diagrid system which has been considered in the Cyclone Tower in Korea (Seven stories below and fifty-one above the ground) was evaluated using the 4 full-scale specimens. The parameters are the extended length (20 mm, 40 mm & 60 mm), thickness (40 mm & 50 mm).

• Proceedings of the KIEE Conference
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• 2000.07c
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• pp.1800-1802
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• 2000

본 연구에서는 냉음극 발광 소자인 FEA를 이용하여 Cold Cathode Lamp 제작과 그 구조에 대해서 연구하였다. Anode plate에는 ZnO:Zn 형광체를 전기영동법으로 증착한 후 tube slabs와 anode plate를 frit glass를 이용하여 접합하였다. FEA와 substrate의 bonding, addressing을 위한 wire bonding, substrate와 집속전극, setter를 stem base의 외부전극에 연결하기 위한 spot welding, tube와 stem base를 glass melting method로 접합 공정을 하였다. 진공배기 시스템에 배기판을 연결하여 ${\sim}10^{-7}$torr까지 배기한 후 heater를 이용하여 배기관을 tip-off하였다. 최종적으로 진공을 유지하기 위해 getter를 RF 고주파로 활성화하였다. 결론적으로 lamp외 특성을 비교분석한 후 휘도 및 발광효율을 향상시키기 위한 구조절 개선과 방안을 고찰하였다.

• Journal of computational fluids engineering
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• v.19 no.3
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• pp.20-23
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• 2014

The flow pattern inside the inlet chamber of the tube side is one of the key parameters influencing on the performances of the shell-and-tube type of heat exchangers(STHE). In order to improve the flow distribution, the baffle shaped as the porous plate is installed in the inlet chambers. In the present study, numerical simulation has been performed to investigate the flow features of the tube side of the STHE in sense of the hydraulic performances. The flow fields have been analysed by the three-dimensional Navier-Stokes solvers with the proper turbulent models. Computational domain is ranged in the whole of the tube side of the STHE. The numerical results showed that the presence of the baffles improves the redistribution of the flow injecting to the tube bundels. The good agreements of the numerical results with the experimental results of PIV measurements have been shown for the validation of the numerical methods adopted in the present papers.

• Transactions of the Korean Society of Pressure Vessels and Piping
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• v.7 no.4
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• pp.51-56
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• 2011

Steam generator is one of the main equipments that affect safety and long term operation in nuclear power plants. Fluid flows inside and outside of the steam generator tubes and induces vibration. To prevent the vibration the tubes are supported by AVB (anti vibration bar). When the steam generator tube contact to AVB, it is damaged by the accumulation of wear and corrosion. Therefore studies are required to determine the effects of the gap between the steam generator tube and AVB. In order to obtain the stress and the displacement distributions of the steam generator tube, three dimensional finite element analyses were performed by using the commercial program ANSYS. Using the calculated the stress and the displacement distributions, the static residual strength of the steam generator tube can be evaluated. The results show that the stress and displacement of the steam generator tube increase significantly compared with the results from a zero-gap model.