• Title/Summary/Keyword: Reactive Fuel

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Non-ignition Evaluation Method for Hypergolic Propellant Using Microreactor (마이크로 반응기를 이용한 접촉점화 추진제의 비점화 평가 방법)

  • Lee, Kyounghwan;Park, Seonghyeon;Kang, Hongjae;Lee, Jongkwang
    • Journal of the Korean Society of Propulsion Engineers
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    • v.26 no.2
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    • pp.20-27
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    • 2022
  • Hypergolic propellant ignited spontaneously when fuel and oxidizer contact without ignition system. Due to this characteristic, the risk of accidents is high when new propellants are evaluated. Prevention of accidents is very important because the damage can be large when the accident occur. In this work, we proposed non-ignition evaluation method which can replace conventional ignition evaluation method by using microreactor. The reactor was fabricated by MEMS. The heat of reaction as according to fuel and NaBH4 was estimated. At the condition of highest heat of reaction ignition was observed by drop test.

Design of a Photovoltaic PCS with Compensation Control of Reactive Power and Unbalance Current in Three-phase systems (3상 시스템의 무효전력, 불평형 전류 보상 기능을 갖는 태양광 전력변환장치 설계)

  • Park, Sang-Min;Kim, Chang-Soon;Le, Dinh Vuong;Park, Minwon;Yu, In-Keun
    • Journal of Korea Society of Industrial Information Systems
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    • v.21 no.3
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    • pp.29-33
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    • 2016
  • Development of the distributed energy resources such as photovoltaic, wind, and fuel cell has increased rapidly due to the rising demand for clean energy utilization. On the other hand, the distribution system became complex and has problems such as degradation of power factor and current unbalance caused by power converters, reactive power and unbalanced loads. To solve these problems, this paper proposes a 3-phase 4-leg type power conditioning system with compensation control algorithm for the reactive power and unbalance current in distribution system using photovoltaic resource. It is simulated in PSCAD/EMTDC and the effectiveness is confirmed.

Three-Phase Z-Source Hybrid Active Power Filter System (3상 Z-소스 하이브리드 능동전력필터 시스템)

  • Lim, Young-Cheol;Kim, Jae-Hyun;Jung, Young-Gook
    • The Transactions of the Korean Institute of Power Electronics
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    • v.15 no.1
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    • pp.75-85
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    • 2010
  • In this paper, a Z-source hybrid active power filter is proposed to compensate the harmonics and reactive power in power distribution system. The proposed system is composed of a 7th harmonics-tuned passive filter and an active power filter with a Z-source inverter topology, while voltage source PWM inverter or current source PWM inverter are applied as the power converter topology of conventional active power filters. The Z-source impedance network along with shoot through capability would ensure a constant DC voltage across the DC link. A polymer electrolyte membrane fuel cell is employed as an compensation DC energy source of the proposed system and its equivalent R-L-C circuit is modeled for simulation. As the compensation and control algorithm of the proposed system, the current synchronous detection algorithm is applied. The simulation analysis by PSIM is performed under the three-phase 220V/60Hz voltage source and 25A nonlinear diode loads. The effectiveness of the proposed the system is verified in the steady and transient states.

OPF with Environmental Constraints with Multi Shunt Dynamic Controllers using Decomposed Parallel GA: Application to the Algerian Network

  • Mahdad, B.;Bouktir, T.;Srairi, K.
    • Journal of Electrical Engineering and Technology
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    • v.4 no.1
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    • pp.55-65
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    • 2009
  • Due to the rapid increase of electricity demand, consideration of environmental constraints in optimal power flow (OPF) problems is increasingly important. In Algeria, up to 90% of electricity is produced by thermal generators (vapor, gas). In order to keep the emission of gaseous pollutants like sulfur dioxide (SO2) and Nitrogen (NO2) under the admissible ecological limits, many conventional and global optimization methods have been proposed to study the trade-off relation between fuel cost and emissions. This paper presents an efficient decomposed Parallel GA to solve the multi-objective environmental/economic dispatch problem. At the decomposed stage the length of the original chromosome is reduced successively and adapted to the topology of the new partition. Two subproblems are proposed: the first subproblem is related to the active power planning to minimize the total fuel cost, and the second subproblem is a reactive power planning design based in practical rules to make fine corrections to the voltage deviation and reactive power violation using a specified number of shunt dynamic compensators named Static Var Compensators (SVC). To validate the robustness of the proposed approach, the algorithm proposed was tested on the Algerian 59-bus network test and compared with conventional methods and with global optimization methods (GA, FGA, and ACO). The results show that the approach proposed can converge to the near solution and obtain a competitive solution at a critical situation and within a reasonable time.

Y2O3-stabilized ZrO2, Ni, and graphene-added Mg by reactive mechanical grinding processing for hydrogen storage and comparison with Ni and Fe2O3 or MnO-added Mg

  • Song, Myoung Youp;Choi, Eunho;Kwak, Young Jun
    • Journal of Ceramic Processing Research
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    • v.20 no.6
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    • pp.609-616
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    • 2019
  • The optimum powder to ball ratio was examined, which is one of the important conditions in reactive mechanical grinding processing. Yttria (Y2O3)-stabilized zirconia (ZrO2) (YSZ), Ni, and graphene were chosen as additives to enhance the hydriding and dehydriding rates of Mg. Samples with a composition of 92.5 wt% Mg + 2.5 wt% YSZ + 2.5 wt% Ni + 2.5 wt% graphene (designated as Mg-2.5YSZ-2.5Ni-2.5graphene) were prepared by grinding in hydrogen atmosphere. Mg-2.5YSZ-2.5Ni-2.5graphene had a high effective hydrogen-storage capacity of almost 7 wt% (6.85 wt%) at 623 K in 12 bar H2 at the second cycle (n = 2). Mg-2.5YSZ-2.5Ni-2.5graphene contained Mg2Ni phase after hydriding-dehydriding cycling. Mg-2.5YSZ-2.5Ni-2.5graphene had a larger quantity of hydrogen absorbed for 60 min, Ha (60 min), than Mg-2.5Ni-2.5graphene and Mg-2.5graphene. The addition of YSZ also increased the initial dehydriding rate and the quantity of hydrogen released for 60 min, Hd (60 min), compared with those of Mg-2.5Ni-2.5graphene. Y2O3-stabilized ZrO2, Ni, and graphene-added Mg had a higher initial hydriding rate and a larger Ha (60 min) than Fe2O3, MnO, or Ni and Fe2O3-added Mg at n = 1.

Comparison of Corrosion Behavior of CrN Coated SUS316L with Different Layer Structure for Polymer Electrode Membrane Fuel Cell Bipolar Plate (CrN 코팅구조에 따른 Polymer Electrode Membrane Fuel Cell 금속분리판의 부식특성 비교)

  • Paik, Jung-Ho;Han, Won-Kyu;Kang, Sung-Goon
    • Korean Journal of Materials Research
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    • v.20 no.4
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    • pp.187-193
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    • 2010
  • Chromium nitride (CrN) samples with two different layer structures (multilayer and single layer) were coated on bipolar plates of polymer electrolyte membrane fuel cells (PEMFC) using the reactive sputtering method. The effects with respect to layer structure on corrosion resistance and overall cell performance were investigated. A continuous and thin chromium nitride layer ($Cr_{0.48}\;N_{0.52}$) was formed on the surface of the SUS 316L when the nitrogen flow rate was 10 sccm. The electrochemical stability of the coated layers was examined using the potentiodynamic and potentiostatic methods in the simulated corrosive circumstances of the PEMFC under $80^{\circ}C$. Interfacial contact resistance (ICR) between the CrN coated sample and the gas diffusion layer was measured by using Wang's method. A single cell performance test was also conducted. The test results showed that CrN coated SUS316L with multilayer structure had excellent corrosion resistance compared to single layer structures and single cell performance results with $25\;cm^2$ in effective area also showed the same tendency. The difference of the electrochemical properties between the single and multilayer samples was attributed to the Cr interlayer layer, which improved the corrosion resistance. Because the coating layer was damaged by pinholes, the Cr layer prevented the penetration of corrosive media into the substrate. Therefore, the CrN with a multilayer structure is an effective coating method to increase the corrosion resistance and to decrease the ICR for metallic bipolar plates in PEMFC.

Remediation of Bunker Fuel Oil C Contaminated Soil with Microwave Radiation and Heating Elements (마이크로파 조사와 발열체를 이용한 벙커C유 오염토양의 복원)

  • Oh, Da-kyung;Lee, Tae-jin
    • Journal of Korean Society of Environmental Engineers
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    • v.37 no.8
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    • pp.458-464
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    • 2015
  • Total petroleum hydrocarbon (TPH) removal and temperature variations in bunker fuel oil C contaminated soil were investigated by using microwave radiation in the presence of triiron oxide or activated carbon as a heating element. Temperature increments of $1.4{\sim}1.6^{\circ}C/Watt$ were observed, when 100~500 watt of microwave radiation was applied for the contaminated soil in the presence of triiron oxide or activated carbon. Temperature variation of the soil was more rapid in the presence of triiron oxide than activated carbon. 10% or 25% of heating element content was required to reach the temperature of thermal desorption for triiron oxide and activated carbon respectively. After radiation, 44.1% and 89.4% of initial TPH in soil was removed in the presence of triiron oxide and activated carbon respectively. It was observed that activated carbon was more reactive than triiron oxide for the removal of high molecular carbon of bunker fuel oil C.

Chlorination of TRU/RE/SrOx in Oxide Spent Nuclear Fuel Using Ammonium Chloride as a Chlorinating Agent

  • Yoon, Dalsung;Paek, Seungwoo;Lee, Sang-Kwon;Lee, Ju Ho;Lee, Chang Hwa
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.20 no.2
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    • pp.193-207
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    • 2022
  • Thermodynamically, TRUOx, REOx, and SrOx can be chlorinated using ammonium chloride (NH4Cl) as a chlorinating agent, whereas uranium oxides (U3O8 and UO2) remain in the oxide form. In the preliminary experiments of this study, U3O8 and CeO2 are reacted separately with NH4Cl at 623 K in a sealed reactor. CeO2 is highly reactive with NH4Cl and becomes chlorinated into CeCl3. The chlorination yield ranges from 96% to 100%. By contrast, U3O8 remains as UO2 even after chlorination. We produced U/REOx- and U/SrOx-simulated fuels to understand the chlorination characteristics of the oxide compounds. Each simulated fuel is chlorinated with NH4Cl, and the products are dissolved in LiCl-KCl salt to separate the oxide compounds from the chloride salt. The oxide compounds precipitate at the bottom. The precipitate and salt phases are sampled and analyzed via X-ray diffraction, scanning electron microscope-energy dispersive spectroscopy, and inductively coupled plasma-optical emission spectroscopy. The analysis results indicate that REOx and SrOx can be easily chlorinated from the simulated fuels; however, only a few of U oxide phases is chlorinated, particularly from the U/SrOx-simulated fuels.

A Study on Characteristics of an Integrated Urea-SCR Catalytic Filter System for Simultaneous Reduction of Soot and NOX Emissions in ECU Common-rail Diesel Engines (ECU 커먼레일 디젤기관에 있어서 매연 및 NOX 배출물 동시 저감용 일체형 요소-SCR 촉매필터 시스템의 특성에 관한 연구)

  • Bae, Myung-Whan
    • Transactions of the Korean Society of Automotive Engineers
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    • v.22 no.4
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    • pp.111-120
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    • 2014
  • The aim of this study is to develop an integrated urea-SCR catalytic filter system for reducing soot and $NO_X$ emissions simultaneously in diesel engines. In this study, the characteristics of exhaust emissions relative to reactive activation temperature under four kinds of engine loads are experimentally investigated by using a four-cycle, four-cylinder, direct injection type, water-cooled turbo intercooler ECU common-rail diesel engine with the integrated urea-SCR $MnO_2-V_2O_5-WO_3/TiO_2/SiC$ catalytic filter system operating at three kinds of engine speeds. The urea-SCR reactor is used to reduce $NO_X$ emissions, and the catalytic filter system is used to reduce soot emissions. The reactive activation temperature is very important for reacting a reducing agent with exhaust emissions. The reactive activation temperatures in this experiment is applied to 523, 573 and 623 K. The fuel is sprayed by the pilot and main injections at the variable injection timing between BTDC $15^{\circ}$ and ATDC $1^{\circ}$ according to experimental conditions. It is found that the $NO_X$ conversion rate is the highest as 83.9% at the reactive activation temperature of 523 K in all experimental conditions of engine speed and load, and the soot emissions shown by the average reduction rate of approximately 93.3% are almost decreased below 0.6% in all experimental conditions regardless of reactive activation temperatures. Also, the THC and CO emissions by oxidation reaction of Mn, V and Ti are shown in the average reduction rates of 70.3% and 38% regardless of all experimental conditions.

A study on the reduction of the flow-induced noise in turbo-charger diesel engines (터보 차져 디젤 엔진에서의 기류음 감소를 위한 연구)

  • Kang, Woong;Kim, Hyung-Jin;Sung, Hyung-Jin
    • Proceedings of the KSME Conference
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    • 2007.05b
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    • pp.2913-2917
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    • 2007
  • Turbocharger has been widely used in many passenger cars in application with diesel engines because of high power and fuel efficiency. However, flow-induced noise (whoosh or hissing noise) which is generated within the compressor during its operation at marginal surge line can deteriorate noise characteristics. Hissing noise excitation was associated with the generation of turbulence within the turbocharger compressor and radiated through the transmission path in turbocharger system. In this study, a sharp-edged reactive-type muffler was devised and installed in the transmission path to reduce the hissing noise. Acoustic and fluid dynamic characteristics for the muffler were investigated which is related to the unsteadiness of turbulence and pressure in turbocharger system. A transfer matrix method was used to analyze the transmission loss of the muffler. Simple expansion muffler with extended tube of the reactive type is proposed for the reduction of high frequency component noise. Turbulence computation was carried out by a standard ${\kappa}-{\varepsilon}$ model. An optimal design condition of the muffler was obtained by extensive acoustic and fluid dynamic analysis on the engine dynamometer with anechoic chamber. A significant reduction of the hissing noise was achieved at the optimal design of the muffler as compared with the conventional turbocharger system.

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