• Journal of the Korean Society of Propulsion Engineers
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• v.15 no.2
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• pp.56-61
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• 2011

Performance test of a full-scale turbopump assembly for a 75 ton class liquid rocket engine was carried out at full speed. Model fluid was used as a working medium: liquid nitrogen for the oxidizer pump, water for the fuel pump, and hot air for the turbine. The turbopump was operated stably, satisfying the performance requirements. Head coefficient and flow coefficient of the pumps remained constant at the speed-increasing period. In terms of performance characteristics of pumps and turbine, the results from the turbopump assembly test showed a good agreement with those from the turbopump component tests.

• 한국연소학회:학술대회논문집
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• 2003.12a
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• pp.125-130
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• 2003

본 논문에서는 액체로켓엔진에서 터보펌프의 160kW급 터빈을 구동하고, 액체산소와 케로신을 추진제로 사용하는 가스발생기의 설계점 연소성능시험 결과에 대해 논의하였다. 충돌형 F-O-F 인젝터, 물냉각 채널을 가진 연소실, torch ignitor, turbulence ring 그리고 측정 링을 갖는 가스발생기에 대해 기술하였고, 점화, 연소, 종료 등의 시험 cyclogram에 대해 언급하였다. 설계점에서의 연소시험 및 turbulence ring 장착여부, 연소실 길이 변화에 따른 연소시험의 결과들에 대해 기술하였다. 연소시험 결과 가스발생기는 설계점에서 안정된 작동성을 보여주었고, 연소압력 및 온도 등의 성능이 예측치에 근접하는 결과를 보여 주었다. Turbulence ring은 출구에서의 가스온도를 균일하게 분포시켜 효과적인 혼합 장치임을 보여 주었고, 4-6msec 정도에서의 잔류시간에서는 연소효율의 차이가 크지 않음을 알 수 있었다. 가스발생기 출구에서의 온도는 공급되는 추진제의 O/F ratio에 따라 매우 민감하게 반응함을 알 수 있었다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.11a
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• pp.27-32
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• 2010

Performance test of a full-scale turbopump assembly for a 75 ton class liquid rocket engine was carried out at full speed. Model fluid was used as a working medium: liquid nitrogen for the oxidizer pump, water for the fuel pump, and hot air for the turbine. The turbopump was operated stably, satisfying the performance requirements. Head coefficient and flow coefficient of the pumps remained constant at the speed-increasing period. In terms of performance characteristics of pumps and turbine, the results from the turbopump assembly test showed a good agreement with those from the turbopump component tests.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.04a
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• pp.57-60
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• 2011

The spray characteristics according to the recess length of the GCSC injector and the change of momentum flux ratio(MFR) of the gas and the liquid have been examined through high pressure cold flow test using a high pressure chamber. The liquid in this experiment was water, and the gas was nitrogen. The spray images were taken by a back-lit strobe imaging technique. Results showed that the spray was a wide hollow cone at the lower MFR(liquid velocity was fixed) and the spray became a narrow solid cone as the MFR was increased. And the injector with short recess length produced a narrow solid cone at the higher MFR.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.47-58
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• 2005

Rice straw is one of the main renewable energy sources in Korea, and bio-oil is produced from rice straw with a lab. scale plant equipped mainly with a fluidized bed and a char removal system. We investigated how the reaction temperature affected the production of bio-oil and the efficiency of a char removal system. To elucidate how the temperature depended on the production of bio-oil, experiment were conducted between $450^{\circ}C\;and\;600^{\circ}C$ with a feed rate of about 300g/h. The mass balance was established in each experiment, and the produced gas and oil were analyzed with the aid of GCs and a GC-MS system. The char removal system is composed of a cyclone and a hot filter. In the experiments, we observed that the optimum reaction temperature range for the production of bio-oil is between $450^{\circ}C\;and\;500^{\circ}C$.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.12 no.1
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• pp.51-57
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• 2013

Leak detection, the system is controlled by humanity's precious water resources, prepare for natural disasters and prevent damage to buildings and various industrial facilities. Especially because it causes serious environmental pollution, chemicals or oil spills, leak detection of various liquid(oil, water), the point at which the liquid leak is detected early on, and minimize environmental pollution, prevent damage of the equipment due to the leak, and the country's precious water resources to be used safely. In this paper, we solve these problems by using specialized film sensor, any person who is not a skilled technician, equipment or walls anywhere can be easily installed. also reduce unnecessary circuit, If film sensor is connected to operate, have a big competitive price, the detection of liquid and the surrounding environment according to, the sensor film that can set the sensitivity control, and monitoring system was implemented.

• Journal of the Earthquake Engineering Society of Korea
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• v.3 no.2
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• pp.19-28
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• 1999

While the codifying works or the earthquake resistant design codes for buildings and bridges have been carried out progressively, such works for tank structures are still at the beginning steps. In case of the collapse of tank structures under seismic actions, substantially severe damages are expected due to the spillage of tank contents in addition to the direct economic losses of tanks and contents. Therefore not only the analysis and verification methods for the dynamic behavior of tank structures but also the measures of minimizing the damage propagation should be included in the codes for tank structures. In this paper the design concepts and principles, the analysis and verification methods as well as the measures against the damage propagation are set forth, which are mandatory for the preparation of the earthquake resistant design codes for cylindrical liquid-storage steel tanks.

• Journal of Convergence for Information Technology
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• v.11 no.2
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• pp.107-116
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• 2021

In this study, an analytical method was developed for estradiol-17��, testosterone, and progesterone, which are growth promoters as veterinary drug residues in animal food. The analytes were separated using liquid chromatography, and was injected into a mass spectrometer through the electrospray ionization(ESI) process and detected in multiple reaction monitoring(MRM) mode. As the method was validated by CODEX CAC/GL 71-2009 guideline, it met the acceptable. The analysis of beef, pork, and chicken distributed in Korea was conducted with an established method to confirm the applicability of the actual sample. It was confirmed that the developed method can be quickly and reliably in the analysis for the growth promoters identified in domestic distributed livestock products. Through subsequent research, a highly utilized analysis method will be completed if the number of growth promoters is expanded based on the method and the simultaneous analytical method is established by including all of it.

• Membrane Journal
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• v.32 no.3
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• pp.173-180
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• 2022

Presence of ammonia in drinking water is very toxic to human health. Soluble ammonia contaminates ground water due to activities such as the use of fertilizer in crop, industrial effluents and burning of fossil fuel. Even low concentration of ammonia present in water will damage aqua environment such as marine organism. Membrane technology is an important process to remove ammonia from effectively from water. Flat sheet membrane, membrane contactor and membrane distillation are some of the methods used for water purification from ammonia. Membrane contractor is an efficient process in which ammonia is removed through liquid-gas or liquid-liquid mass transfer without change of phase unlike membrane distillation. However, the cost of ammonia removal in this method is high due to maintenance of very high pH. Zeolite has excellent ion exchange ability that enhances its ability to interact with ammonia and adsorb from wastewater. Mixed matrix membranes containing zeolite enhance the efficiency of ammonia adsorption and separation from wastewater. In this review the above discussed issues are summarized in detail.

• Journal of Aerospace System Engineering
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• v.13 no.6
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• pp.9-16
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• 2019

The experiment on the liquid jet in crossflow in supersonic BFS (backward-facing step) flow was conducted to investigate the mixing characteristics. The working fluids are nitrogen and water. The shadow graph technique was used to visualize the flow field. Images captured by the high-speed camera were applied to analyze the flow phenomena. The liquid jet was injected at the re-circulation zone created by the supersonic jet flow. Experimental conditions are defined based on the pressure of the nitrogen gas chamber and pressurized liquid tank. In respective cases, the penetration depth of liquid jet and location of the Mach disc were observed to be proportional to the momentum ratio of gas and liquid jets.