• Journal of Advanced Navigation Technology
• /
• v.18 no.2
• /
• pp.107-113
• /
• 2014

In this paper, controller Propose to prevent compressor surge and improve the transient response of the fuel flow control system of turbojet engine. Turbojet engine controller is designed by applying Artificial Neural Network PID control algorithm and make an inference by applying Artificial Neural Network Error Back Propagation Algorithm. To prevent any surge or a flame out event during the engine acceleration or deceleration, the ANN PID controller effectively controls the fuel flow input of the control system. ANN PID results are used as the fuel flow control inputs to prevent compressor surge and flame-out for turbo-jet engine and the controller is designed to converge to the desired speed quickly and safely. Using MATLAB to perform computer simulations verified the performance of the proposed controller. Response characteristics pursuant to the gain were analyzed by simulation.

• Transactions of the Korean hydrogen and new energy society
• /
• v.23 no.2
• /
• pp.134-142
• /
• 2012

A bipolar plate is a major component of a fuel cell stack, which occupies 50~60% of the total weight and over 50% of the total cost of a typical fuel cell stack. In this study, a composite bipolar plate is designed and fabricated to develop a compact and light-weight direct methanol fuel cell (DMFC) stack for a small-scale Unmanned Aerial Vehicle (UAV) application. The composite bipolar plates for DMFCs are prepared by a compression molding method using resole type phenol resin as a binder and natural graphite and carbon black as a conductor filler and tested in terms of electrical conductivity, mechanical strength and hydrogen permeability. The flexural strength of 63 MPa and the in-plane electrical conductivities of 191 S $cm^{-1}$ are achieved under the optimum bipolar plate composition of phenol : 18%; natural graphite : 82%; carbon black : 3%, indicating that the composite bipolar plates exhibit sufficient mechanical strength, electrical conductivity and hydrogen permeability to be applied in a DMFC stack. A DMFC with the composite bipolar plate is tested and shows a similar cell performance with a conventional DMFC with graphite-based bipolar plate.

• Journal of Advanced Navigation Technology
• /
• v.24 no.1
• /
• pp.1-8
• /
• 2020

In this research, we develop an airborne equipment radiating S/C-band signal to a target located at a long distance. RF interface of the equipment comprises band-specific transmitters and an broadband antenna to satisfy EIRP(effective isotropic radiated power) requirements. The equipment is in a shape of a POD like an aircraft fuel tank. The measured weight of the equipment is 119.8 kg, the CG(center of gravity) is 1391.35 mm and the MOI(moment of inertia) are 46.07 ± 0.05(I_yy) kg·㎡, 45.36 ± 0.09(I_zz) kg·㎡. All results are found to meet the requirements for aircraft installation. To verify flight safety, EMI(electromagnetic interference) tests (RE102, CE102), environmental tests (high/low temperature operation, altitude), intra-system EMC(electromagnetic compatibility) and HERP(hazards electromagnetic radiation personnel) tests have been conducted and all the test results met the requirements. It is confirmed that the equipment could be mounted on the aircraft by meeting all electrical and mechanical requirements.

• Membrane Journal
• /
• v.20 no.4
• /
• pp.267-277
• /
• 2010

Gas separation membranes have been developed for decades in various areas to replace the conventional processes. Membrane processes for gas separation have many advantages of energy saving, compact size, and easy scale-up. Nowadays, gas separation processes is widely spreaded in nitrogen generating system, hydrogen generating system, membrane dryer, on board inert gas generating system, natural gas purification, biogas purification and fuel cells. Carbon dioxide separation process using membrane would be a strong candidate of carbon dioxide capturing process. In order to broaden the scope of application of gas separation membranes, development of new materials which can overcome the borderline of Robeson's plot should be necessary, so that many researchers and companies are trying to develop the new materials like polymers containing cardo and spiro group and PIMs (polymers for intrinsic microporosity).

• Korean Chemical Engineering Research
• /
• v.55 no.1
• /
• pp.13-18
• /
• 2017

Sodium borohydride, $NaBH_4$, shows a number of advantages as hydrogen source for UAV PEMFC (Unmaned Aerial Vehicle Proton Exchange Membrane Fuel Cells). In order to use for UAV, the weight and volume of byproduct should be small after $NaBH_4$ hydrolysis reaction. Therefore, the weight and volume of byproduct were studied after $NaBH_4$ hydrolysis reaction using unsupported catalyst. The effect of catalyst type, concentration of $NaBH_4$, concentration of NaOH and thickness of catalyst pack on the weight and volume of byproduct were studied. Most of byproduct was $NaB(OH)_4$ and superficial volume of byproduct increased due to foam evolved from byproduct. The weight and volume of byproduct were not affected by concentration of NaOH used stabilizer. The weight of byproduct decreased as concentration of $NaBH_4$ solution increased, but maximum volume of byproduct obtained at 23 wt% of $NaBH_4$. Suitable defoaming agent reduced the volume of byproduct.

• 한국방재학회:학술대회논문집
• /
• 2011.02a
• /
• pp.194-194
• /
• 2011

현대 사회에서 차량을 비롯한 선박, 항공기와 같은 각종 수송수단들은 그 용도와 형태도 다양하고 널리 보급되어있을 뿐만 아니라 각 분야에서 없어서는 안 될 필수품이 되어 있다. 그러나 수송수단의 수와 활용빈도수가 증가함에 따라 그로 인한 차량화재, 선박화재 그리고 항공기화재 등과 같은 특수화재의 발생에 따른 재산 및 인명피해의 문제점들도 함께 늘어나고 있는 실정이다. 2009년 기준, 1년 동안의 전체 화재발생건수 47,071건 가운데 차량화재의 발생건수가 5,958건으로서 전체의 12.6% 정도를 차지하였다. 그뿐만 아니라 차량 내장재의 주 재질은 가연성을 지닌 열가소성 합성수지들로서 화재가 발생하였을 경우, 다량의 가연성 가스 및 독성가스를 방출하기 때문에 인명 및 재산 피해를 증가시키는 문제점을 갖고 있다. 하지만 아직까지도 이와 같은 수송수단에 대한 화재를 예방하거나 피해를 최소화할 수 있는 화재진압대책 등에 관한 연구는 미흡한 실정이다. 따라서 본 연구에서는 이러한 문제점을 해결하고 과학적이며 체계적인 대응방안을 수립하기 위한 기초 자료를 확보하고 이를 통한 수송수단의 화재안전성을 분석하고자 각종 수송수단에서 사용되는 오일을 대상으로 연소특성 분석 및 화재하중에 관한 연구를 수행하였다. 분석 대상 오일은 연료용과 부속용 오일로 크게 분류되며, 연료용 오일로는 차량용 경유와 휘발유 그리고 군용차량용 경유, 항공기용 백등유와 제트유, 선박용 고유황경유 등을 선정하였다. 부속용 오일로는 브레이크오일, 파워오일, 엔진오일, 자동변속기오일, 수동변속기오일을 대상으로 각각 일반용과 고급형 2가지씩 시료를 선정하여 분석을 수행하였다. 분석방법은 대상오일들의 기초물성을 고찰하기 위해서 비중계를 이용하여 각 시료들의 비중을 측정하였으며, 문헌으로부터 끓는점, 어는점 및 점도 등을 조사하였다. 또한, 대상오일들의 착화특성을 살펴보고자 콘칼로리미터와 인화점 측정기 및 발화점 측정기 등을 이용하여 발열량, 착화시간, 발연량, 발화점, 인화점 등을 측정하였다. 대상오일들의 물성 및 착화특성에 대한 측정결과를 살펴보면, 비중은 $725.8{\sim}1072.0kg/m^3$ 정도의 값을 나타냈고, 인화점은 영하의 인화점을 갖는 휘발유의 경우, 장비의 특성상 분석이 곤란하여 측정하지 못하였으며, 다른 시료들은 $45.3{\sim}266.6^{\circ}C$정도의 값을 나타냈다. 발화점은 $325.7{\sim}600.6^{\circ}C$정도의 값을 갖는 것으로 나타났다. 따라서 이와 같은 결과들을 활용하면 차량, 선박, 항공기 등에 대한 화재발생과 관련된 화재안전성을 분석하고 이를 통한 수송시스템의 화재에 대한 예방 및 대응 방안의 효율성을 높일 수 있을 것으로 생각된다.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.22 no.5
• /
• pp.15-21
• /
• 2021

Electrically powered airplanes can reduce CO₂ emissions from fossil fuel use and reduce airplane costs in the long run through efficient energy use. For this reason, advanced aviation countries such as the United States and the European Union are leading the development of innovative technologies to implement the full-electric airplane in the future. Currently, the research and development to convert existing two-seater engine airplanes to electric-powered airplanes are underway domestically. The airplane converted to electric propulsion is the KLA-100, which aims to carry out a 30-minute flight test with a battery pack installed using the engine mounting space and copilot space. The lithium-ion battery installed on the airplane converted to electric propulsion was designed with a specific power of 150Wh/kg, weight of 200kg, and a C-rate 3~4. This study confirmed the possibility of a 30-minute flight with a designed battery pack before conducting a flight test of a modified electrically propelled airplane. The battery performance was verified by dividing the 30-minute flight profile into start/run stage, take-off stage, climbing stage, cruise stage, descending stage, and landing/run stage. The final target of the 30-minute flight was evaluated by calculating the battery capacity required for each stage. Furthermore, the flight performance of the electrically propelled airplane was determined by calculating the flight availability time and navigation distance according to the flight speed.

• Journal of the Korean Society of Propulsion Engineers
• /
• v.2 no.3
• /
• pp.99-106
• /
• 1998

The performance of the turbofan engine, a medium scale civil aircraft which has been developing in Rep. of Korea, was analyzed and the control scheme for optimization the performance was studied. The dynamic and real-time linear simulation was performed in the previous study The result was that the fuel scedule of the step increase overshoot the limit temperature(3105 $^{\cire}R$) of the high pressure turbine and got small surge margine of the high pressure compressor. Therefore a control scheme such as the LQR(Linear Quadratic Regulator) was applied to optimizing the performance in this studies. The linear model was expected for designing controller and the real time linear model was developed to be closed to nonlinear simulation results. The system matrices were derived from sampling operating points in the scheduled range and then the least square method was applied to the interpolation between these sampling points, where each element of matrices was a function of the rotor speed. The control variables were the fuel flow and the low pressure compressor bleed air. The controlled linear model eliminated the inlet temperature overshoot of the high pressure turbine and obtained maximum surge margins within 0.55. The SFC was stabilized in the range of 0.355 to 0.43.

• Korean Chemical Engineering Research
• /
• v.54 no.1
• /
• pp.11-15
• /
• 2016

Proton Exchange Membrane Fuel Cells (PEMFC) instead of batteries is appropriate for long time flight of unmanned aero vehicles (UAV). In this work, $NaBH_4$ hydrolysis system supplying hydrogen to PEMFC was studied. In order to decrease weight of $NaBH_4$ hydrolysis system, enhancement of hydrogen yield, recovery of condensing water and maintenance of stable hydrogen yield were studied. The hydrogen yield of 3.4% was increased by controlling of hydrogen pressure in hydrolysis reactor. Condensing water formed during air cooling of hydrogen was recovered into storage tank of $NaBH_4$ solution. In this process the condensing water dissolved $NaBH_4$ powder and then addition of $NaBH_4$ solution decreased system weight of 14%. $NaBH_4$ hydrolysis system was stably operated with hydrogen yield of 96% by 2.0g Co-P-B catalyst for 10 hours at 2.0L/min hydrogen evolution rate.