• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.65-66
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• 1997

1. 서론 : 현재의 막분리 기술로는 단 단계 분리공정(single-stage separation)으로 약 40%의 산소농축공기(oxygen-enriched air)를 얻을 수 밖에 없지만 심냉법(cryogenic techniques)보다는 에너지 소비율이 적으며, 공정이 비교적 간단하기 때문에 용도에 따라 순 산소를 꼭 필요로 하지 않는 제철소, 발전소 등의 연소분야, 호흡기 환자를 위한 의료분야, 생물공학이나 항공기 분야 등에 편리하게 이용될 수 있다. 이와 같이 용도가 다양한 산소를 분리막을 이용하여 보다 편리하고 값싸게 얻기 위해서는 산소와 질소의 막투과에 대한 새로운 지식을 얻고 막투과가 기체의 어떤 성질에 지배되고 있는가를 조사할 필요가 있다. 본 연구에서는 고무상 고분자막(rubbery polymer membrane)에 대한 산소/질소의 수착특성과 순수한 기체의 투과율(permeation rate)을 기초로 하여 혼합기체의 투과율, 분리인자(separation factor), 막분리 공정변수에 의한 중공사 분리막에서의 기체분리특성에 대하여 연구하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.107-110
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• 2008

The test range for turbopump and gas generator coupled test was determined considering the engine system test area which cover the qualification and development. Based on the test range, we determined the required loss coefficient for the throttle valves and lines.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2001.11a
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• pp.90-93
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• 2001

In the present work, ultrasonic testing method has been developed to evaluate adhesive layers in rocket motor case assembly for the reliability of the rocket. The main objective of the present work was to find debonding between steel and rubber layers. The relationship between adhesion ratio and reflected ultrasonic amplitude was calculated by considering reflection coefficient at the interface between steel and rubber layers. It was found that the higher amplitude of ultrasound is reflected for the debonding area, and shown good agreements with experimental results. The ultrasonic C-scan images offers good implements for the determination of debonding area. The nondestructive testing results were compared with the micrography of destruective testing. As results, ultrasonic testing could be utilized for the evaluation of adhesive layer in the rocket motor case assembly.

• Journal of Aerospace System Engineering
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• v.14 no.5
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• pp.26-32
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• 2020

In this study, a facility was constructed to supply liquid nitrogen to simulate combustion instability in a liquid rocket combustor. The pressurization and supply performances were predicted and verified through different experiments. The liquid nitrogen supply system was composed of a pressurized supply system, and a dome regulator was used to adjust the pressure of the pressurant. A cavitation venturi was used to control the mass flow rate of liquid nitrogen. The condition of liquid nitrogen supply was a mass flow rate of 2.55 kg/s and the venturi inlet pressure was above 100 bar. Based on the initial experiment, it was observed that the predicted amount of the pressurant was not sufficiently supplied and the target pressure was not supplied due to a drop in tank pressure. Through the modification of the established facilities, the target mass flow rate was successfully supplied and the cryogenic liquid nitrogen supply facility was verified.

• Journal of the Korean Society of Propulsion Engineers
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• v.14 no.2
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• pp.29-38
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• 2010

The experimental study on paraffin wax/LDPE blended fuel for hybrid rocket was performed. Various combustion characteristics of blended fuel were compared with pure paraffin, HTPB, HDPE and SP-1a fuel in order to evaluate the performance of blended fuel. The regression rate of lab-scale and large-scale motor using pure paraffin fuel was increased by 10.2 and 9.8 factor when respectively compared to that of HDPE. The regression rate factor of blended fuel was 3.4 in which the regression rate of blended fuel was higher than that of HTPB and HDPE, but lower than that of pure paraffin, SP-1a fuel. The values of characteristic velocity and specific impulse of blended fuel was higher than those of pure paraffin, HTPB and HDPE, and almost the same as SP-1a fuel. As these results, it was confirmed that blended fuel can be an effective solid fuel for hybrid rocket.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.8 no.2
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• pp.207-211
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• 2007

It is a quite quality concerning to control the temperature of single crystalline growth as it does when we get most of heat treating products. It is also important factor to control the temperature when we make the $Al_2O_3$(single crystalline) used to artificial jewels, glass of watches, and heat resistant transparent glasses. Thus, it is a major interest to get the proper temperature in accordance with the time process while we are making mixture of oxygen and hydrogen to have the right temperature. In this paper, we will study of electrical valve positioning system with DC-Motor for the gas mixture to improve the quality of products.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.18 no.5
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• pp.420-427
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• 2017

Recently, the depletion of fossil fuels, global warming and environmental pollution have emerged as a worldwide problem, and studies of new renewable energy sources have been progressed. Among the many renewable energy sources, the use of bio fuel has the potential to displace fossil fuels due to low price, easy to handle, and the abundant sources. Pyrolysis oil (PO) derived from waste wood and sawdust is considered an alternative fuel for use in diesel engines. On the other hand, PO is limited to diesel engines because of its low cetane number, high viscosity, high acidity, and low energy density. Therefore, to improve its poor properties, PO was mixed with alcohol fuels, such as ethanol. Early mixing with ethanol has the benefit of improving the storage and handling properties of the PO. Furthermore, a PO-ethanol blended fuel was injected separately, which can be fired through pilot-injected diesel in a dual-injection diesel engine. The experimental results showed that the substitution of diesel with blended fuel increases the amount of HC and CO, but reduces the NOx and PM significantly.

• Journal of the Korean Institute of Gas
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• v.23 no.1
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• pp.27-35
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• 2019

In order to solve the global warming and reduce greenhouse gas emissions, $CO_2$ capture technology was developed by applying oxy-fuel combustion. But there has been such a problem that its economic efficiency is low due to the high price of oxygen gases. ASU is known to be most suitable method to produce large quantity of oxygen, to reduce the oxygen production cost, the efficiency of ASU need to be improved. To improve the efficiency of ASU, exergy analysis can be used. The exergy analysis provides the information of used energy in the process, the location and size of exergy destruction. In this study, the exergy analysis was used for process developing and optimization of large scale ASU. The process simulation of ASU was conducted, the results were used to calculate the exergy. As a result, to reduce the exergy loss in the cold box of ASU, a lower operating pressure process was suggested. It was confirmed the importance of heat leak and heat loss reduction of cold box. Also, the unit process of ASU which requires thermal integration was confirmed.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.3 no.2
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• pp.103-113
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• 1991

This paper presents a method for estimating the noise source contribution of a pulse combustion burner in a multiple input system where the input sources may be coherent each other. By coherence function method, it is found that the biggest part of the noise source in the pulse combustion burner is generated by the part of the combustion chamber. This analysis is modeled as three input / single output system because the noise generating mechanism of the pulse combustion burner is very complicated. The coherence function method is proved to be useful tool for the identification of noise source. The overall levels of the radiated source pressure by coherence function method are compared with those measured and calculated by the frequency response function approach. The experimental results have shown a good agreement with the results calculated by the coherence function method when the input sources are coherent strongly each other. The estimation of shield effect by FRF method indicates that significant reduction can be achieved in sound radiation if only transmission path generated by the part of combustion chamber is acoustically shield.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.31 no.8
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• pp.85-90
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• 2003

To control spacecraft including satellite, we should understand precisely the performance of propulsion system and the program logic with appropriate format for satellite operations. In this study, the thruster performance functions was generated by using the best curve fitting for performance data from bi-propellant thrusters. Detailed thruster performance data are, in general, company proprietary information, therefore real firing tests were performed to understand the basic characteristics of the performance curve. Experimental rocket motor utilize liquid oxygen and kerosine as propellant and designed average thrust was 100 pound.