• 한국수소및신에너지학회논문집
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• 제29권1호
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• pp.124-129
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• 2018

Methane is the cleanest fuel and supplies by many distributed type: liquefaction natural gas (LNG), compressed natural gas (CNG), and pipeline natural gas (PNG). Natural gas is mainly composed by methane and has been discovered in the oil and gas fields. Coal bed methane (CBM) is also one of them which reserved in coalbed. This significant new energy sources has emerge to convert an energy source, hydrogen and hydrogen-driven chemicals. For this CBM, this paper was written to analyze the geological analysis and reserves in Mongolian Tavan Tolgoi CBM coal mine and to examine the application field. This paper is mainly a preliminary feasibility report analyzing the business of Tavan Tolgoi CBM and its exploitable gas.

• 한국수소및신에너지학회논문집
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• 제29권1호
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• pp.130-137
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• 2018

Now discusses the potential use and applications of coal bed methane (CBM) in various industries. One of the options for gas monetization is gas to power (GTP), sometimes called gas to wire (GTW). Electric power can be an intermediate product, such as in the case of mineral refining in which electricity is used to refine bauxite into aluminum; or it can be an end product that is distributed into a large utility power grid. For stranded gas, away from the regional markets, the integration of the ammonia and urea plants makes commercial sense. These new applications, if established, could lead to a surge in demand for methanol plants.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.227-230
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• 2006

The method of mass flow rate measurement using a critical nozzle is well established in the flow satisfying ideal gas law. However, in the case of measuring high-pressure gas flow, the current method shows invalid discharge coefficient because the flow does not follow ideal gas law. Therefore an appropriate equation of state considering real gas effects should be applied into the method. The present computational study has been performed to give an understanding of the physics of a critical nozzle flow for high-pressure hydrogen gas and find a way for the exact mass flow prediction. The two-dimensional, axisymmetric, compressible Navier-Stokes equations are computed using a fully implicit finite volume method. The real gas effects are considered in the calculation of discharge coefficient as well as in the computation. The computational results are compared with the previous experimental data and predict well the measured mass flow rates. It has been found that the discharge coefficient for high-pressure hydrogen gas can be corrected properly adopting the real gas effects.

• 한국수소및신에너지학회논문집
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• 제21권1호
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• pp.42-49
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• 2010

Increasing environmental concerns regarding the use of fossil fuels and global wanning have prompted researcher to investigate alternative fuels. The purpose of this study is to investigate the syngas production by biogas reforming using a compression spark ignition engine. The parametric screening studies were carried out according to the variations of oxygen enrichment rate, biogas $CO_2$ ratio, intake gas temperature, and engine revolution. When the oxygen enrichment rate and input gas temperature increased, hydrogen and carbon monoxide were increased. But the biogas $CO_2$ ratio and engine revolution increased, the syngas were reduced. For the reforming of methane 100% only, generation of hydrogen and carbon monoxide was 58% and 17%, respectively. However when the biogas $CO_2$ ratio was 40%, hydrogen and carbon monoxide concentration were about 20% each.

• 한국수소및신에너지학회논문집
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• 제24권5호
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• pp.461-466
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• 2013

In this research, the diesel cycle was thermodynamically interpreted to evaluate the possibility of high efficiency by converting diesel engine to the atkinson cycle, and general cycle features were analyzed after comparing these two cycles. That an experimental single cylinder and a long stroke diesel-atkinson engine, of which S/B ratio was more than 3, were manufactured. After evaluating the engine through basic experiments, a diesel engine was converted into the atkinson cycle by constituent VCR (variable compression ratio) device and VVT (variable valve timing) system. The experimental method was to observe compression work reduction effects due to low compression effects from delayed intake valve closing of the early stage atkinson engine. The result, the possibility of increasing compression ratio about each engine load was confirmation by constructing compensate expansion-compression ratio in accordance with the delayed intake valve close.

• Journal of Advanced Marine Engineering and Technology
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• 제28권5호
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• pp.728-734
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• 2004

Environmentally friendly refrigerants with zero ozone layer depletion potential are required to be used in refrigerators and air conditioners due to the difficulties related to ozone layer depletion and global warming. A rigorous study for the system performance with new refrigerants having zero ozone layer depletion potential is inevitable before adopting that as a new fluid. The HFC(Hydrofluorocarbon) potential has been recommended as alternatives. In this paper. system performance in the heat pump facilities were studied using R-290, R-600a. R-1270 as an environment friendly refrigerant. R-22 as a HCFC's refrigerant. The experimental apparatus has been set-up as a conventional vapor compression type heat Pump system. The test section is a horizontal double pipe heat exchanger. A tube diameter of 12.70mm with 1.315mm wall thickness is used for this investigation. The test results showed that the COP of hydrocarbon refrigerants were superior to that of R-22 and the maximum increasing rate of COP was found in R-1270. The refrigeration capacity of hydrocarbon refrigerants were higher than that of R-22. The compressor work was obtained with the maximum value in R-1270 and the minimum one in R-22.

• 한국컴퓨터정보학회:학술대회논문집
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• 한국컴퓨터정보학회 2023년도 제68차 하계학술대회논문집 31권2호
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• pp.7-10
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• 2023

최근 기후 변화가 심각해짐에 따라 수소 에너지에 대한 관심이 집중되고 있으며 이를 안전하게 운송/보관할 수 있는 용기에 대한 연구도 활발히 진행되고 있다. 특히 고압 가스를 저장하는 TypeIII 용기의 노후화 및 안전과 관련되어 결함을 인지하는 연구가 활발하다. 그러나 이 용기의 외각층을 이루는 CFRP 소재는 탄소 섬유와 에폭시가 복잡한 구조로 구성되어 결함별 탐지가 매우 어렵다. 본 논문에서는 음향방출시험과 딥러닝을 활용하여 CFRP 결함 데이터셋을 구축하고 이를 분류할 수 있는 모델을 제안한다. 특히 CFRP 시편을 직접 제작하여 AE 센서를 부착하고 파괴하여 파형 데이터를 수집하였다. 이후 표현 학습을 통해 데이터의 특징을 압축/추출하고 유사도를 비교해 결함별 데이터를 판별하는 알고리즘을 개발하였다. 구축된 데이터셋의 실루엣 계수는 0.86으로 높은 군집도를 보였다. 마지막으로 구축된 데이터셋을 실시간으로 분류할 수 있는 1D-CNN 딥러닝 모델을 개발하였으며 99.33%의 높은 분류 정확도를 보였다.

• 한국수소및신에너지학회논문집
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• 제35권1호
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• pp.97-104
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• 2024

In this study, combustion experiments were conducted to assess engine performance and exhaust gas characteristics using four blends of 1-pentanol and diesel as fuel in a naturally aspirated 4-stroke diesel engine. The blending ratios of 1-pentanol were 5, 10, 15, and 20% by volume. The experiments were carried out under four different engine torque conditions (6, 8, 10, and 12 Nm) while maintaining a constant engine speed of 2,000 rpm for all fuel types. The results showed that the use of 1-pentanol/diesel blended fuel generally led to a decrease in brake thermal efficiency, attributed to the low calorific value of the blend and the cooling effect due to the latent heat of vaporization. Additionally, both brake specific energy consumption and brake specific fuel consumption increased. However, the use of the blended fuel resulted in a general decrease in NOx concentration, a decrease in CO concentration except some conditions, and a reduction in smoke opacity across all conditions.

• Elastomers and Composites
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• 제44권1호
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• pp.76-83
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• 2009

본 연구는 비닐작용기의 위치가 다른 실리콘 프리폴리머와 수소작용기의 위치가 다른 가교제, 그리고 이들의 혼합사용이 제조된 치과용 폴리비닐실록산 고무인상재의 물성에 미치는 영향을 연구하였다. 한 종류의 중점도 프리폴리머를 사용한 실험군은 인장강도, 파단신율, 압축시 변형률이 다른 특성의 프리폴리머들을 혼합사용한 경우보다 낮은 값을 보였다. 측부와 말단에 수소작용기가 있는 CR210 가교제를 사용한 실험군은 측부에만 수소작용기가 있는 CR101 가교제를 사용한 실험군에 비해 압축시 변형률과 파단신율이 더 높았다. 측쇄에도 비닐기를 갖는 높은 비닐함량의 프리폴리머를 사용한 경우는 더 높은 인장강도를 보였지만, 경화 속도가 늦어서 임상 사용에 적합한 작업성을 갖는 치과용 인상재를 만들기 위해서는 이 성분이 경화시간에 미치는 영향과 이를 조절할 수 있는 방안에 대한 지속적인 연구가 필요하다고 생각한다.

• 한국자동차공학회논문집
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• 제21권4호
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• pp.106-112
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• 2013

Compression ratio is an important factor affecting engine performance and emission characteristics since thermal efficiency of spark ignition engine can be theoretically improved by increasing compression ratio. In order to evaluate the effect of compression ratio change in HCNG engine, natural gas engine was employed using HCNG30 (CNG 70 vol%, hydrogen 30 vol%). Combustion and emission characteristics of CNG and HCNG fuel was analyzed with respect to the change of compression ratio at each operating condition. The results showed that thermal efficiency improved and $CH_4$, $CO_2$ emission decreased with the increase in compression ratio while $NO_x$ emissions were decreased at a certain excess air ratio condition. Higher thermal efficiency and further reduction of exhaust emissions can be achieved by the increase of compression ratio and the retard of spark timing.