• Proceedings of the KSME Conference
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• 2002.08a
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• pp.47-50
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• 2002

The numerical simulation of a 271-rod fuel assembly of nuclear Liquid-Metal Fast Reactor (LMFR) with an infernal blockage has been carried out. Internal blockage within a subassembly is addressed in the safety assessment because it potentially has very serious consequences for the reactor as a whole. Three dimensional calculations were performed using the SABRE4 computer code for the range of blockage positions and sizes to investigate the seriousness and detectability of the internal blockage. The magnitude and location of the peak temperatures together with the temperature distribution at the subassembly exit were calculated in order to look at the potential for damage within the subassembly, and the possibility of blockage detection. The analysis result shows that the 6-subchannel blockage causes large temperature rise within a assembly with practically no change in mixed mean temperature at the assembly exit.

• Proceedings of the Korean Nuclear Society Conference
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• 2003.05a
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• pp.127.1-127.1
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• 2003

• Proceedings of the Korean Nuclear Society Conference
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• 2004.05a
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• pp.215-215
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• 2004

• Transactions of the Korean Society of Mechanical Engineers B
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• v.37 no.4
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• pp.377-385
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• 2013

To identify the effects of an outflow area on pool boiling heat transfer in a vertical annulus, three different flow restrictors were studied experimentally. For the test, a heated tube of smooth stainless steel and water at atmospheric pressure were used. Both annuli with open and closed bottoms were considered. To validate the effects of the outflow area on the heat transfer, the results of the annulus with the restrictor were compared with the data for the plain annulus without the restrictor. The reduction of the outflow area ultimately results in a decrease in the heat transfer. As the outflow area is very small, a slight increase in heat transfer is also observed. The major cause of this tendency is explained as the difference in the intensity of liquid agitation cause by the movement of coalesced bubbles. It is identified that the convective flow, pulsating flow, and evaporative mechanism are considered as the important mechanisms.

• Clinical and Experimental Pediatrics
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• v.50 no.7
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• pp.660-664
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• 2007

Purpose : Pleural effusion is a common complications of pediatric bacterial pneumonia. Intrapleural administration of fibrinolytic agents such as urokinase have been used in the management of complicated parapneumonic effusions. But the safety and effectiveness of intrapleural urokinase instillations in children has not been confirmed. The aim of this study is to evaluate the safety and effectiveness of intraperitoneal urokinase in children. Methods : We reviewed a total of 29 children diagnosed as parapneumonic effusion with septation by chest CT or chest ultrasonography. We divided them into two groups. Fourteen children treated with urokinase after thoracostomy (Group A) were compared with 15 children treated only with thoracostomy (Group B). The urokinase, 3,000 IU/kg/day, was injected into the pleural cavity twice a day. Results : There was no statistical difference in sex and age between the two groups. Total drainage volume during thoracostomy in group A and B was 375.5 mL and 350.0 mL, respectively. It was not statistically significant. But the amounts of pleural fluid of group A on day 1, day 2 and day 3 were 102.5 mL, 100.0 mL, and 70.0 mL respectively and those of group B on day 1, day 2 and say 3 were 120.0 mL, 50.0 mL and 15.0 mL respectively. To compare group A with group B in the amounts of drainage volume on day 1 was not statistically significant, but the amounts of drainage volumes on day 2 and day 3 in group A were statistically more significant than group B (Day 1 P=0.371, Day 2 P=0.049, Day 3 P=0.048, respectively). The duration of fever, antibiotics, thoracostomy and total hospital days. Were not statistically significant between the two groups. But the frequency of complications in Group A was statictically significantly lower than in group B. Conclusion : Intrapleural instillation of urokinase facilitates the drainage of loculated pleural effusions, especially during the first 3 days, and it could reduce complications, such as pleural thickening, surgical managements, re-positioning of tube and re-thoracostomy. So intrapleural urokinase injection was and effective and safe treatment of pleural effusion in children (P=0.014).

• Journal of the Korean Society of Marine Environment & Safety
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• v.15 no.3
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• pp.251-256
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• 2009

In this research, we experimentally studied flow characteristic by applying PIV measuring techniques which could measure the point velocity of all flow field and measuring the unsteady velocity of surrounding disk generated in a short time. Time range of great velocity change following quick closing of the slide valve was within 0.1s and the cycle was presumed to be 0.12s as a result of comparison study between the result of point flow field and of existing pressure change. Also, surrounding disk flow inside the circular pipe was closed from the upper part and flow road was getting narrow and advanced to the lower part incidentally quickly there was a tendency that the size of the flow back velocity to the upper part immeadiately after the closure decreased to 4/120s and increased again. There was flow back velocity component in y/D=0.2 lower part by the influence of flow back to the upper part after complete closure and the vortex flow of 0.2D-size near y/D=0.7, x/D=-0.3 was observed.

• 유체기계공업학회:학술대회논문집
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• 2004.12a
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• pp.405-410
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• 2004

2-dimensional impeller's distinctive feature is expected to have an influence on performance and flow characteristics of centrifugal compressor. And new design method is required for 2-dimensional impeller, because the unique geometry cannot be designed using conventional theories. The objective of this study is to advance new design technology for 2-dimensional impeller and to investigate the performance characteristics of designed 2-dimensional centrifugal compressor. The performance test for 2-dimensional impeller is conducted at 35000, 40000 and 45000rpm. Also numerical calculation is applied by using commercial CFD code, FLUENT, and the results are compared with experimental results.

• Proceedings of the Korean Society of Fisheries Technology Conference
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• 2000.05a
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• pp.220-222
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• 2000

한반도 서해 중부역에 위치한 금강 수계는 국내 4대강의 하나로서 발원지인 전라북도 진안에서 군산하구까지 총 유로연장이 약400km에 달하며, 집수면적은 9880$\textrm{km}^2$으로 담수유출량은 6.4$\times$$10^{9}$ton/year에 이른다. 1988년에 농업용수와 공업용수의 안정적 확보를 목적으로 전라북도 옥구군 성산면 성덕리와 충청남도 서천군 마서면 도산리를 연결하는 총 1,841m길이의 금강하구둑이 건설되었고, 1994년 8월 하구언 갑문이 반 영구적으로 폐쇄됨에 따라 하구해역의 환경변화가 크게 나타날 것으로 예상되었다. (중략)

• Transactions of the Korean Society of Mechanical Engineers B
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• v.31 no.7 s.262
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• pp.604-610
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• 2007

To investigate effects of the inflow area on pool boiling heat transfer in a vertical annulus, the inflow area at its bottom has been changed from 0 to $1060.3mm^2$. For the test, a heated tube of 34 mm diameter and water at atmospheric pressure have been used. To elucidate effects of the inflow area on heat transfer results of the annulus are compared to the data of a single unrestricted tube. The change in the inflow area at the bottom of the annulus results in much variation in heat transfer coefficients. When the inflow area is $113.1mm^2$ the deterioration point of heat transfer coefficients gets moved up to the higher heat fluxes because of the convective flow at the bottom regions.

• Journal of Aerospace System Engineering
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• v.9 no.4
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• pp.67-72
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• 2015

The analysis has been performed on the blockage effect at the propellant flow passage in a liquid rocket engine. This simulates an example of emergency situation where flow passage is partially blocked. The analysis method has been validated by predicting the pump head and flow rate within 1% precision against the measured data of turbopump-gas generator coupled test. When the oxidizer passage is reduced it is predicted that the mixture ratio decreases, the oxidizer pump head increases and the gas generator pressure increases. When the fuel passage is reduced it is predicted that the mixture ratio increases, fuel flow rate decreases and the fuel pump head increases.