• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2012.04a
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• pp.476-479
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• 2012

차량의 충돌에 따른 등유의 누출에 의한 화재와 항공기 충돌에 따른 항공유의 누출에 의한 화재 발생 시 격실의 개구부 크기에 따른 화염온도를 평가하기 위해 화원으로 등유와 Jet-A-1을 사용하고 개구부의 크기를 조절해 가며 격실화재시험을 수행하였으며, 가장 높게 측정된 시험결과의 조건으로 과도화재시험을 수행하여 금속저장용기가 화염온도에 미치는 영향을 평가하였다. 시험결과 등유보다 Jet-A-1의 열 방출속도 및 질량 연소유속이 크게 나타났으며, Jet-A-1에서의 화염온도가 높게 측정되었다. 연료 소모율은 개구부의 크기가 클 경우 작은 경우보다 크게 나타났으며, 개구부의 크기가 클 경우 화염온도가 높게 측정되었다. 격실 내에 금속저장용기가 저장되었을 때는 저장용기가 화염으로부터 받는 열량만큼 화염의 온도는 낮아지는 것으로 나타났다.

• Korean journal of aerospace and environmental medicine
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• v.30 no.3
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• pp.113-129
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• 2020

With the operation of the KC-330 MRTT (Multi Role Tanker Transport), which had been fielded in 2019, the ROKAF (Republic of Korea Air Force) has given fighter pilots a new mission of air refueling. As a result, fighter pilots are more likely to be exposed to risks they have never faced before, and it is necessary to look at the risk factors associated with human factors in air refueling missions. Therefore, in this study, an analysis using the HFACS (Human Factors Analysis and Classification System) model was performed for fighter pilots with air refueling qualifications. This study tried to prevent hazard in advance by discriminating the risk factors according to the human factors related to the fighter pilot during the air refueling mission.

• Asian Journal of Atmospheric Environment
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• v.5 no.4
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• pp.263-277
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• 2011

Global atmospheric $CO_2$ distributions were simulated with a chemical transport model (GEOS-Chem) and compared with space-borne observations of $CO_2$ column density by GOSAT from April 2009 to January 2010. The GEOS-Chem model simulated 3-D global atmospheric $CO_2$ at $2^{\circ}{\times}2.5^{\circ}$ horizontal resolution using global $CO_2$ surface sources/sinks as well as 3-D emissions from aviation and the atmospheric oxidation of other carbon species. The seasonal cycle and spatial distribution of GEOS-Chem $CO_2$ columns were generally comparable with GOSAT columns over each continent with a systematic positive bias of ~1.0%. Data from the World Data Center for Greenhouse Gases (WDCGG) from twelve ground stations spanning $90^{\circ}S-82^{\circ}N$ were also compared with the modeled data for the period of 2004-2009 inclusive. The ground-based data show high correlations with the GEOS-Chem simulation ($0.66{\leq}R^2{\leq}0.99$) but the model data have a negative bias of ~1.0%, which is primarily due to the model initial conditions. Together these two comparisons can be used to infer that GOSAT $CO_2$ retrievals underestimate $CO_2$ column concentration by ~2.0%, as demonstrated in recent validation work using other methods. We further estimated individual source/sink contributions to the global atmospheric $CO_2$ budget and trends through 7 tagged $CO_2$ tracers (fossil fuels, ocean exchanges, biomass burning, biofuel burning, net terrestrial exchange, shipping, aviation, and CO oxidation) over 2004-2009. The global $CO_2$ trend over this period (2.1 ppmv/year) has been mainly driven by fossil fuel combustion and cement production (3.2 ppmv/year), reinforcing the fact that rigorous $CO_2$ reductions from human activities are necessary in order to stabilize atmospheric $CO_2$ levels.

• Journal of Advanced Navigation Technology
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• v.19 no.3
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• pp.175-181
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• 2015

Method establishment needs for recent shortening the flight path, fuel reduction, reduction of the flight delay time, increase of the route capacity like as relieve congested airspace and solving future demand. However, As the existing conventional navigation systems is impossible to be resolved. Hereupon, SBAS has been developed with using the GNSS. ICAO has recommended that SBAS need to be operated with aircraft operation from 2025, korea is also developing KASS in accordance with the recommendation. In this paper, before the 2022 KASS will be completed, KASS can be expected using for flight test and inspection as analyzing KASS flight test and relative specifications.

• Journal of Aerospace System Engineering
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• v.13 no.6
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• pp.70-79
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• 2019

The increase of bird strike requires to be amended more safely current airworthiness requirements for bird strike. The USA and Europe are considering the methodology to verify the bird strike requirements based on the finite element analysis (FEA). Meanwhile, the aircraft airworthiness standards in Korea enacted by the Ministry of Land, Infrastructure and Transport were based on those enacted by the Federal Aviation Administration (FAA). This means that the verification methods using the FEA for the bird strike requirements should be reflected in the airworthiness standards in Korea. Our study proposes the methodology for bird strike simulation based on the FEA for the external auxiliary fuel tank assembly on the Surion helicopters and confirmed that the numerical outputs corresponded to the test results. The authors suggest that the methodology and procedure based on the FEA are adopted not only in the bird strike requirements but in various aircraft certifications of civilian rotorcraft.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.39 no.6
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• pp.485-496
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• 2015

The present study presents experimental results on the characteristics of emission spectra of kerosene/air swirl flames. The aviation fuel Jet A-1, which is used for the liquid rocket engines of the Korea Space Launch Vehicle, is used with three different swirlers to investigate the swirl strength effects. The emission spectra from the flames are measured with a spectrometer as the swirl strength and combustion air temperature are varied. Chemiluminescence intensities of $OH^*$, $CH^*$ and $C_2{^*}$ are identified from the spectra. The chemiluminescence intensities from the kerosene flames show sensitivity to the swirl strength and are affected by changes in the combustion air temperature. Among the three radicals of interest, $C_2{^*}$ show the most significant changes in chemiluminescence intensity with the swirl strength and equivalence ratio. The intensity ratios $I_{OH^*}/I_{CH^*}$ and $I_{C_2{^*}}/I_{CH^*}$ are adequate for indicating changes in the equivalence ratio with the air and fuel mass flow rates, respectively.

• Journal of Advanced Navigation Technology
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• v.10 no.4
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• pp.319-326
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• 2006

In this paper, a fuzzy inference control system is proposed for a turbojet engine with fuel flow control input only. The proposed control system provides a practical fuel flow control method to prevent surge or flame out during engine acceleration or deceleration. A fuzzy logic is designed to obtain the fast acceleration and deceleration of the engine under the condition that the operating point should stay between the surge line and flame out control line. With using both engine rotating speed error and surge margin as fuzzy input variables, the desired engine rotating speed can be achieved to rapidly follow the engine control line without engine stall. Computer simulation using the MATLAB is realized to prove the proposed control performance to the turbojet engine which is linear modelized using DYGABCD program package.

• Journal of Aerospace System Engineering
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• v.17 no.6
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• pp.72-81
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• 2023

Hydrogen-fueled gas turbines are a promising technology that can resolve the carbon dioxide emission issue as future aviation propulsion engines and carbon-free power generations. To achieve high efficiency and stability of gas turbines using 100% hydrogen as fuel, an innovative design of combustor systems is necessary to consider the characteristics of hydrogen, which are different from those of conventional hydrocarbon fuels. Micromix is a combustor design method, which aims to terminate the reaction quickly by intense mixing of fuel and air, consequently reducing NOx and increasing the stability. In this paper, we examine the principles and design process of micromix combustors as a pure-hydrogen combustion technology, and we introduce a design of a 30 kW micromix hydrogen combustor for research.

• International Journal of Aeronautical and Space Sciences
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• v.16 no.2
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• pp.311-324
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• 2015

This study presents computational analyses for low-drag aerodynamic design that are applied to modify a long-endurance UAV. EAV-2 is a test-bed for a hybrid electric power system (fuel cell and solar cell) that was developed by the Korean Aerospace Research Institute (KARI) for use in future long-endurance UAVs. The computational investigation focuses on designing a wing with a reduced drag since this is the main contributor of the aerodynamic drag. The airfoil and wing aspect ratio of the least drag are defined, the fuselage configuration is modified, and raked wingtips are implemented to further reduce the profile and induced drag of EAV-2. The results indicate that the total drag was reduced by 54% relative to EAV-1, which was a small-sized version that was previously developed. In addition, static stabilities can be achieved in the longitudinal and lateral-directional by this low-drag configuration. A long-endurance flight test of 22 hours proves that the low-drag design for EAV-2 is effective and that the average power consumption is lower than the objective cruise powerof 200 Watts.

• Composites Research
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• v.25 no.4
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• pp.105-109
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• 2012

Recently, development of a small aircraft has been carried out for the BASA(Bilateral Aviation Safety Agreement) program in Korea. This aircraft adopted all composite structures for environmental friendly by low fuel consumption due to its lightness behavior. However the composite structure has disadvantage which is very weak against impact damages. Therefore, damage allowable design of aircraft structure must be performed considering compressive fracture strength. This point is very important for certification of composite structure aircraft. In this paper, it is performed the research on damage tolerance of thick laminate adopting aircraft structure. The damage tolerance of three different types of thick laminates such as no damage, open hole and impact damage is evaluated under compression loading.