• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 한국추진공학회 2007년도 제29회 추계학술대회논문집
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• pp.139-143
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• 2007

The overall results of combustion tests performed for a 30 tonf-class full-scale combustion chambers of a liquid rocket engine were described. The combustion chambers have chamber pressure of 53${\sim}$60 bar and propellant mass flow rate of 89 kg/so The combustion chamber is composed of mixing head, SUS baffle, baffle injector, ablative chamber, channel cooling chamber and regenerative cooling chamber. The test results show that the combustion characteristic velocity is in the range of 1673${\sim}$1730 m/sec and the specific impulse of the combustion chamber is in the range of 254${\sim}$263 sec. As the recess number of the injectors increases, the combustion characteristic velocity increases. And as the combustion characteristic velocity increases, the specific impulse of the combustion chamber also increases.

• Korean Journal of Plant Tissue Culture
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• 제27권2호
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• pp.83-87
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• 2000

To investigate the effect of growth regulators and antioxidant in anther floating cultures of rice, anthers were cultured in liquid media supplemented with different growth regulators, and the effect of antioxidant mixture : (Sigma Chemical Co.) on callus induction and plant regeneration were investigated. N6 medium with 1 mg/L 2,4-D and 1 mg/L kinetin was the best for rice anther floating cultures, which showed 48.5% of callus induction and 6.8% of green plant regeneration. The callus induction was not affected by antioxidant mixture in liquid medium, and antioxidant mixture (250 mg/L) was effective for the reduction of brownish callus and improvement of plant regeneration Antioxidant mixture showed better effectiveness when it was supplemented to both media for callus induction and plant regeneration.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• 제16권3호
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• pp.347-357
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• 2018

The applicability of room temperature ionic liquids (RTILs), 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([$C_nmim$] [$Tf_2N$]), was investigated for the extraction of Am(III) and Eu(III) from nitric acid using n-octyl(phenyl)-N,N-diisobutyl carbamoylmethyl phosphine oxide (CMPO) and tri-n-butylphosphate (TBP) as extractants. The distribution ratios of Am(III) and Eu(III) in CMPO-TBP/[$C_nmim$][$Tf_2N$] were measured as a function of various parameters such as the concentrations of nitric acid, CMPO, and TBP. The results were compared with those obtained in CMPO-TBP/n-dodecane (n-DD). With comparable concentrations of the extractants, the distribution ratios obtained with RTILs were much higher than those obtained with n-DD. It was observed that the extraction efficiency was less for Eu(III) than for Am(III). The extraction of Am(III) and Eu(III) decreased with increases in the feed acidity for all three RTILs. The results suggest that the extraction of Am(III) and Eu(III) by CMPO in RTILs from nitric acid proceeds through the cation-exchange mechanism. The distribution ratios of Am(III) and Eu(III) increased with increases in the concentration of CMPO for all three RTILs. A linear regression analysis of the extraction data resulted in a straight line with a slope of about 3, suggesting the involvement of 3 molecules of CMPO during the extraction process.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제43권7호
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• pp.585-592
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• 2015

Effects of opening distance on liquid-gas spray of pintle injector were experimentally investigated under atmospheric condition by using water and air as simulants of propellants. Discharge coefficients($C_d$) and mass flow rates were calculated with various injection conditions; 0.1 bar - 1.0 bar for water pressures and 0.2 mm - 1.0 mm for the pintle opening distances. Spray angles were measured from the spray images that were obtained by a shadowgraphy method. When opening distance is 0.2 mm, liquid sheet is not formed properly and it show non-uniform spray. than it can result in combustion instability. it has a weak correlation between the momentum flux ratio and the spray angle, while it has a strong correlation between the momentum ratio and spray angle. Finally the spray angles reduced exponentially when the momentum ratio increased and the spray angles converged to about 40 degrees.

• Fire Science and Engineering
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• 제28권4호
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• pp.14-20
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• 2014

The purpose of this study is to analyze combustion patterns by filling a specific container with a flammable liquid and performing combustion tests in a divided space. The container used for the test is made of plastic, 20 mm in depth and 150 mm in width. After the liquid was ignited, its combustion process was photographed using a digital camera and video camera. It was found that in the case of benzene, the flame reached its peak at the fastest speed about 60 s while in the case of alcohol, the flame reached its peak at the lowest speed about 360 s, which is approximately six times slower than the benzene. In most cases, when the flame reached its peak, smoke generated was dark as the plastic container and flammable liquid were combusted simultaneously. After completion of the combustion, it was possible to sample oil vapor from all flammable liquids excluding soybean oil as a result of the examination of oil vapor using a crime investigation tube. That is, it can be seen that there is significant difference in flame propagation speed, pattern, etc., depending on the combustible substances.

• Journal of the Korean Society of Propulsion Engineers
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• 제11권4호
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• pp.38-45
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• 2007

A liquid rocket engine fuel-rich gas generator has been developed for the first time in the country, which can produce combustion gas over the rate of 4 kg/s at 900 K and 58 bar. The gas is not only for driving a turbopump but also for providing heat source for propellant supply tanks. The final design of the gas generator had been fixed based on the concept and preliminary development tests, and was validated through structure and heat transfer analysis. The manufacturing involved precision machining, surface finish, and special welding technique. The final assessment on the characteristics of ignition and combustion had been carried out for two different versions of injector heads. This concluded that the present product satisfies the development requirements such as spatial temperature distribution and the development has been successful.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제38권12호
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• pp.1195-1201
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• 2010

Performance tests of a supersonic exhaust diffuser were conducted by using a liquid rocket engine for simulating high-altitude environment. The experimental setup consisted of a combustion chamber, a vacuum chamber and a diffuser. The combustion tests for simulating high-altitude environment were carried out at three cases by chamber pressure variation(26, 29, 32barg). The test results showed that the diffuser was started at all case and vacuum chamber pressures were approximately 140torr. The starting pressure using combustion gas was similar with that of cold gas, but the vacuum chamber pressure was relatively high because of high temperature in the vacuum chamber. The results of this test can be used as an essential database for the design of real-scale high-altitude simulation test facility in the future.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• 제30권6호
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• pp.46-52
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• 2002

Characteristics of flow rate control has been studied for a cavitating venturi adopted in a liquid rocket propellant feed system. Both experiment and numerical simulation have been performed to give about 10% discrepancy of mass flow rate for cavitating flow regime. Mass flow rate is confirmed to be saturated for pressure difference higher than $3{\times}10^5$pa when the upstream pressure is fixed to $22.8{\times}10^5$pa and the downstream pressure is varied. The evaporation amount depends substantially to non-condensable gas concentration. However the mass flow rate characteristics is relatively insensitive to the mass fraction of non-condensable gas. So it reduces by only 2% when the non-condensable gas concentration is increased from 1.5PPM to 150PPM. From the previous comparison the expansion of the non-condensable gas and the evaporation of liquid are verified to gave same effect to the pressure recovery pattern.

• Proceedings of the Plant Resources Society of Korea Conference
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• 한국자원식물학회 2010년도 정기총회 및 추계학술발표회
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• pp.19-19
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• 2010

황칠나무(Dendropanax morbifera Lev.)는 두릅나무과(Araliaceae)에 속하며 학명에서 뜻하는 바와 같이 목본 (Dendro), 전능약(Panax)이라는 의미가 있고 나무인삼이라 불리기도 하며 줄기에 상처를 내면 노란액이 나온다고 해서 황칠나무(D. morbifera)라는 이름이 붙여졌다. 두릅나무과는 우리나라에서 최고의 약재들로 손꼽히는 인삼(Panax ginseng), 가시오갈피(Eleutherococcus senticosus) 등의 약용식물을 포함하고 있어서 황칠나무는 황칠수지액 이외에 약용식물로서의 무한한 개발 가능성을 내포하고 있다. 따라서 본 실험은 황칠나무의 기내 부정근 유도 및 증식조건의 확립을 목적으로 수행되었다. 우선 황칠나무의 기내 발아체로부터 부위(잎, 줄기, 뿌리)를 달리하여 부정근을 유도한 결과, 잎은 줄기나 뿌리보다 양호한 부정근의 유도를 보였다. 또한 유도된 부정근을 이용하여 옥신의 종류에 따른 부정근 유도율을 조사한 결과 IBA와 NAA는 IAA와 2.4-D보다 높은 유도율을 보였다. IBA의 농도에 따른 유도율과 증식효율은 IBA가 1.0 mg/L 첨가되었을 때 가장 높은 유도 및 증식효율을 보였다. 최적의 액체배지조건을 확인하고자 sucrose의 농도와 염농도를 달리하여 실험한 결과 1/2MS 배지는 MS 배지보다 10%정도 높은 증식율을 보였다. 액체배양 된 황칠나무의 부정근을 각각 1/2MS 배지에 30 g/L sucrose, 3.0 mg/L IBA가 첨가된 5 L volume 생물반응기에 4주 간 배양한 대조구와 2주 후 IBA의 농도를 1.0으로 낮추어 배양한 실험구에서 2주후 IBA의 농도를 낮추어 배양한 실험구에서 대조구보다 약 2배 높은 부정근의 증식량을 보였다. 결국, 황칠나무의 종자발아체를 이용하여 부정근의 유도 및 증식조건에 필요한 기내배양조건을 확립하였고, 플라스크와 생물반응기 배양을 통해 효율적인 실험실 내 증식조건을 확립하였다. 본 실험결과는 향후 황칠나무 천연추출물을 활용한 향장품/식,의약품 소재의 대량확보 차원에서 중요한 가치를 내포하고 있다고 조심스럽게 사료된다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 한국추진공학회 2010년도 제35회 추계학술대회논문집
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• pp.72-76
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• 2010

To research and develop a high performance injector for LRE, it needs not only cold flow test, but also investigations of combustion performance, optimization of cyclogram and thermo-fluid dynamical characteristics of combustion flow field through hot-fire test. In this study, hot-fire test of LOX-CH4 coaxial swirl injector has been carried out using lab-scale hot fire test stand which can supply and control cryogenic propellant. Ignition and continuous combustion for LOX-$GCH_4$ propellant of 0.19 kg/s total mass flowrate and 2.80 O/F Ratio was achieved through cyclogram optimization. The mean combustion chamber pressure and thrust were measured as approximately 1.43 MPa and 38.7 kgf respectively.