• Fire Science and Engineering
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• v.19 no.1 s.57
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• pp.70-89
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• 2005

Fire scenarios in a space $20.0m\;\times\;4.0m$ floor and 3.0m high were simulated by using computational fluid dynamics program (FDS 4.0.3) to investigate the effect of the combined operation of both sprinkler and vent systems, which are installed for cooling and blocking smoke which propagates beneath the ceiling of a horizontal corridor, on the temperature and smoke density of it. It was shown that the combined operation both sprinkler and vent systems was more effective than each operation for cooling and blocking smoke, the number of operating sprinklers was two because of corner effect of wall, and over-installed sprinklers deteriorated the effect of cooling and blocking smoke. This study showed that the case of two sprinklers and vent flow rate $3.0m^3/s$ in fire scenario was the most effective for cooling and blocking smoke. It was confirmed that the smoke downdrag occurs in operating sprinkler system, and the more smoke droplets produced by increasing fire size, the greater smoke downdrag occurred.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.636-641
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• 2010

A preburner for the staged combustion in the high performance liquid rocket engine is being developed and strength experiments and finite element analyses on specimens, which simulate the brazing joint of the preburner, were performed and the results were compared. One specimen simulate the joints near oxygen injectors of head by the funance brazing and two specimens the joints of the combustion chamber cooling channel by vacuum brazing. The experiments were burst ones with strain gauges.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.11
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• pp.536-540
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• 2018

As the performance of engines improves, the temperature of engines is increasing, resulting in a high piston temperature. An excessively high piston temperature may result in torque drop or engine failure. An oil jet is used to reduce the piston temperature. In this study, to monitor the effect of oil jet, a templug was used to measure the piston temperature. A templug is a kind of sensor and the hardness of the templug changes according to the piston temperature. Using a templug, the maximum temperature of the piston was measured with and without an oil jet. The piston temperature was lowered using the oil jet. The highest temperature region changed from the center crown to the front/rear area. In addition, the temperature difference between the highest and lowest regions became smaller.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05d
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• pp.176-181
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• 1996

원자로 용기 헤드부위의 관통관은 재질이 Inconel-600이며, 현재 세계각국에서도 원자로 헤드 관통관의 균열이 일부 발견되어 우리나라에서도 관심이 되고 있다. 국내 원전 헤드관 통관 수량도 고리 1,2호기의 경우 40개, 고리3,4호기(영광1,2) 61개, 울진 57개로서 관통관의 균열결함이 존재할 수 있다. 만약 균열이 성장하여 파손 되었을 시 원자로 냉각재 누설등 발전소 안전에 큰영향을 미치므로 균열의 원인으로 알려진 용접부위 잔류응력 및 발전소 정상운전 상태에서의 응력을 해석하였다.

• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.2
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• pp.50-55
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• 2011

A preburner for the high performance, staged combustion cycle liquid rocket engine is being developed. For the structural design processes, strength experiments and finite element analyses on specimens simulating the brazing joints of the preburner, were performed and compared. Total two kinds of the specimen were manufactured for the tests. One simulated the joints between the oxygen injectors and the head junctioned by the conventional vacuum brazing. The another was made to test the brazing surfaces by vacuum compression between the combustion chamber cooling channel and the outer wall. During the burst experiments, it was observed that the fractures were occurred not at the brazed joining but in the middle of the face plate and the cooling wall. In addition, the analysis showed that the predicted fracture locations and the strains were well matched with the experiment results.

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05a
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• pp.824-829
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• 1998

미국의 개량형 원자력 발전소 개념설계단계에서 중대사고시 사고완화를 위한 전략으로 원자로 압력용기 외부냉각 개념이 제안되었다. 중대사고 진행과정에서 노심용융물이 원자로 압력용기 하부헤드로 재배치 되었을 때 압력용기 외벽을 냉각함으로서 노심용융물을 압력용기 내부에 가두어 두어 격납건물 내로의 유출을 방지하는 방식이다. 이 연구에서는 원자로 압력용기 하부헤드 내의 노심용융물 거동중 자연 순환에 의한 거동을 수치적으로 모의하여 보았다. 연구결과, 정상상태의 온도 및 속도분포는 현상학적으로 적절하게 모의되나 고화와 액화의 경우에는 고유모델의 필요성이 요구되었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2017.05a
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• pp.1021-1025
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• 2017

Numerical heat/flow analysis was performed on a liquid rocket engine head with the cooling water manifold to ensure the durability of a ground test facility for heat exchanger. Through these studies, the shapes of the injector and the flow path were determined and applied to the head of the engine under development. Firing tests were conducted to verify the designed coolant manifold and no thermal damage was found on the engine-head-face. Comparing the combustion test results with the numerical analysis, the outlet temperature of coolant showed a difference of about $15^{\circ}C$. This trend is reasonable considering existence of LOX manifold, thermal barrier coating, and the actual location of flame.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05a
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• pp.166-171
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• 1997

LPMS(Loose Part Monitoring System)는 원자로 및 냉각재계통내에서 발생하는 금속파편의 검출 및 분석을 위하여 사용되는 진단 장비이다. 본 논문에서는 RPV(Reactor Pressure Vessel)의 상부헤드(closure head)와 하부헤드(lower head)에서의 금속파편의 충격위치를 평가하는 LPMS를 위한 새로운 기법을 제안하고, Mock-up에서의 실험을 통하여 그 효용성을 검증하였다. 즉, 수정된 원교차법을 제안하고, 이를 반구로 모델링된 RPV의 상ㆍ하부헤드에 존재하는 금속파편의 위치평가에 적용하므로써 정확한 충격위치를 찾을 수 있음을 보였다. 이들 결과는 충격물질의 질량이나 에너지를 계산하는데 정확한 정보를 제공해 줄 수가 있다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.31-34
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• 2011

Design and fabrication of Technology Demonstration Model(TDM) of 75 tonf regenerative cooling thrust chamber were described. It has design chamber pressure of 60 bar, propellant mass flow rate of 243.6 kg/s, and nozzle expansion ratio of 12. It has a single welded structure of the mixing head and the chamber. Design and fabrication technologies established through this TDM can be used to development of flight model.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2007.04a
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• pp.128-134
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• 2007

Combustion performance and characteristics of high-pressure subscale liquid rocket combustors were studied experimentally. Four different models of combustor were considered in this paper. The high-pressure subscale combustor is composed of the mixing head, the water cooling cylinder and the nozzle. One model of the combustors employed regenerative cooling combustor in that the kerosene used for the chamber cooling is burned. This combustor was damaged due to a high frequency combustion instability occurred during a firing test. The results of the firing tests, comparison of performance, and characteristics of static and dynamic pressures of the combustors are described.