• Journal of Conservation Science
• /
• v.27 no.2
• /
• pp.231-241
• /
• 2011

Anoxia Treatment using inert gas like nitrogen and argon has been used to eradicate insects successfully in museums as alternative of methyl bromide and toxic insecticide. Killing efficacy of insect for anoxia treatment is depend on species of insects, oxygen concentration, temperature, relative humidity and gas. It is possible to kill museum insects which are most tolerant in anoxia environment, within 1 month below 0.03% of oxygen concentration in temperature $15{\sim}25^{\circ}C$ and relative humidity 40~60% of museum environment. And various systems like bag, tent, bubble and chamber depending on size and quantity of objects, are used.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2003.10a
• /
• pp.78-82
• /
• 2003

The cooling mechanism for a regenerative cooling liquid rocket engine of 10tf-thrust using kerosene as a fuel was studied from the viewpoint of curtain cooling. Based on the concept of a highly-stratified gas flow in the combustion chamber, the cross section of the combustion chamber was spilt into 2 independent parts, core and exterior part. Additional fuel is injected into the exterior section and gas temperature can be reduced in the exterior section. Consequently, the heat flux into the coolant and wall temperature are reduced and the thermal stability of a liquid rocket engine could be improved.

• Journal of the Korean Society for Aeronautical & Space Sciences
• /
• v.31 no.10
• /
• pp.66-72
• /
• 2003

The cooling mechanism for a liquid rocket engine of 10tf-thrust using kerosene as a fuel was studied from the viewpoint of both the regenerative and curtain cooling. Based on the concept of a highly-stratified gas flow in the combustion chamber, the cross section of the combustion chamber was spilt into 2 independent parts, core and exterior part. Additional fuel is injected into the exterior section and gas temperature can be reduced in the exterior section. Consequently, the heat flux into the coolant and wall temperature are reduced and the thermal stability of a liquid rocket en g i.ne could be improved.

• Resources Recycling
• /
• v.11 no.6
• /
• pp.47-54
• /
• 2002

Copper concentrate particles were fed from the top of vertical reaction tube of 2.8 cm ID and 65 cm long with an $O_2$-$N_2$ gas mixture. The reaction tube was heated to 1000 K to 1400 K. The copper concentrate particles were very rapidly oxidized and melted down during their descent in the reaction tube. The particle temperature were calculated by combining an unreacted core model, mass transfer between gas and particles, and heat transfer between gas, particles and tube wall. The particle temperature reached its maximum at the height of 20 to 30 cm from the top of the reaction tube, and it attained about 1700 K at higher oxy-gen partial pressure. The most particles were melted at the oxygen partial pressure above 0.2 atm.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2017.05a
• /
• pp.734-738
• /
• 2017

In the present study, dominant factors for temperature increase and effects of mass entering the resonance tube of the gas-dynamic igniter are investigated. Using RhoCentralFoam solver in OpenFOAM program, numerical simulation is performed for three different cases. In the results, the heating of the working fluid is found to be a result from aero-thermodynamic phenomena. Appropriate mass entering to the resonance tube is found to be an important dominant factor as well.

• Proceedings of the Korea Information Processing Society Conference
• /
• 2019.10a
• /
• pp.746-749
• /
• 2019

자유 단조는 고온에 가열한 강괴에 높은 압력을 가하여 원하는 형상의 제품을 만드는 공정으로 에너지 소모가 매우 크다. 여러 개의 강괴를 가열로에 장입하여 고온에 가열한 후 소재를 하나씩 꺼내어 프레스 공정을 수행한다. 가열로에 함께 장입되는 소재들의 조합에 따라 가열 시 소요 시간 및 에너지 사용량이 달라진다. 소재 조합에 따른 가열 비용 예측을 통해 최적의 소재 조합을 결정하여 에너지 효율을 높일 수 있다. 비용 예측 모형을 학습하기 위해서는 가열 소요 시간 및 에너지 사용량 데이터가 필요하다. 따라서 본 논문에서는 가열로의 온도 및 가스 사용량 데이터를 이용하여 가열로의 가동 상태 변경 지점을 감지하는 방안을 제안한다. 가열로의 온도 및 가스 사용량은 IoT 인프라를 기반으로 손 쉽게 획득할 수 있다. 가열로의 상태 별로 온도 및 가스 사용량에 나타나는 패턴을 이용하여 상태 변경 지점을 감지한다. 이를 통해 가열 공정 데이터를 획득할 수 있을 뿐만 아니라 가열로의 상태를 실시간에 모니터링이 가능함으로써 불필요하게 가열하는 것을 예방하여 에너지 효율을 높일 수 있다.

• Korean Chemical Engineering Research
• /
• v.52 no.6
• /
• pp.821-825
• /
• 2014

Steam gasification of sawdust char was performed in a thermobalance reactor at high temperature. Gasification temperature was changed from $850^{\circ}C$ to $1400^{\circ}C$ and steam partial pressure was 0.3, 0.5 and 0.7 atm. Three models of gas-solid reaction were applied to the reaction kinetics analysis and modified volumetric model was an appropriate model. Reaction control regime and diffusion control regime were distinct depending on the temperature. Apparent activation energy and pre-exponential factors for both of the regimes were evaluated and the effects of steam partial pressure were examined. $H_2$ concentration in the produced gas was two times higher than that of CO due to the gasification accompanying by the water gas shift reaction.

• Aerospace Engineering and Technology
• /
• v.6 no.1
• /
• pp.128-135
• /
• 2007

Combustion characteristics of full-scale gas generators were studied experimentally by changing the injector number installed at the injector head. Three full-scale gas generators were utilized; they have same total mass flow rate but mass flow rates per injector are different. Thirteen, nineteen and thirty seven injectors, which have internal-mixing and double-swirl characteristics, are distributed in injector heads, respectively. The results showed that pressure fluctuations in the gas generators with 13 and 19 injectors didn't occur around longitudinal resonant frequency, however longitudinal-mode pressure fluctuation appeared slightly in the gas generator with 37 injectors. As the number of injectors increased, deviations of temperature distribution in the combustion chamber decreased gradually, but the damage of injector LOx posts became a little severe.

• 한국신재생에너지학회:학술대회논문집
• /
• 2011.05a
• /
• pp.145.2-145.2
• /
• 2011

메탄 하이드레이트는 낮은 온도와 높은 압력 조건에서 물분자들의 격자구조에 메탄가스분자가 포획되어 수소결합으로 형성되는 외관상 얼음과 비슷한 결정성 화합물이다. $1m^3$의 메탄 하이드레이트는 표준상태에서 $172m^3$의 메탄가스와 $0.8m^3$의 물로 분해되며, $-10^{\circ}C{\sim}-20^{\circ}C$의 온도에서는 하이드레이트 입자표면에서 생성되는 얼음막으로 인하여 상압에서도 안정하게 존재하는 자기보존 효과를 가지고 있다. 따라서 이와 같은 특징을 천연가스 수송 및 저장의 방법으로 이용할 경우 $-162^{\circ}C$의 초저온을 만들고 유지시키기 위하여 고가의 설비를 필요로 하는 기존의 LNG 수송방법을 대체할 수 있다. 특히 연간 천연가스 소비량을 0.4 ~ 1.0 million ton으로 가정했을 때, 하이드레이트 수송방법은 LNG 수송에 비해 18 ~ 25% 정도의 비용을 절약할 수 있는 경제적인 방법으로 알려져 있다. 그러나 하이드레이트를 인공적으로 제조할 경우 물분자와 가스분자의 반응율이 낮기 때문에 하이드레이트가 생성되기까지 많은 시간이 소요되며, 하이드레이트에 포획되는 가스분자의 양도 적다. 따라서 본 연구에서는 이와 같은 문제점을 해결하기 위하여 다공성 물질인 천연 제올라이트와 제올라이트 13X를 이용하여 제올라이트 혼합유체를 제조하였으며, 메탄가스와 반응시켜 하이드레이트를 생성시키는 실험을 수행하였다. 그 결과, 하이드레이트 생성 시 천연 제올라이트와 제올라이트 13X 모두 0.01 wt%의 혼합비율에서 가장 좋은 효과를 나타내었으며, 하이드레이트에 포획된 가스의 양은 같은 과냉도 조건에서 천연제올라이트와 제올라이트 13X 혼합유체를 이용하여 하이드레이트를 생성 시켰을 때, 증류수보다 각각 4배, 5배 높음을 보였다. 또한 낮은 과냉도에서 하이드레이트 생성 시 제올라이트, 제올라이트13X 혼합유체에서 하이드레이트 생성시간이 증류수에서 하이드레이트를 생성시킬 때보다 빨라짐을 확인하였다.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.11 no.4
• /
• pp.38-45
• /
• 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.