• Title/Summary/Keyword: Fuel Particles

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A Study on Combustion Characteristics of Paraffin Blended Fuel on Aluminum Particle Size (알루미늄 입자 크기에 따른 파라핀 혼합연료의 연소 특성 연구)

  • Ko, Soohan;Han, Seongjoo;Ryu, Sunghoon;Kim, Jinkon;Moon, Heejang;Kim, Junhyung;Ko, Seungwon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.791-796
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    • 2017
  • In this study, the combustion characteristics of paraffin blended fuel on aluminum particle size were investigated. The combustion experiments were carried out using aluminum particles with an average particle size of 100 nm and $8{\mu}m$ and microcrystalline paraffin wax (Sasol 0907). A series of comparison was conducted on the regression rate, the pressure curve and the characteristic velocity of pure paraffin and paraffin blended fuels with aluminum particles. It was found that the micro-sized particles enhance the regression rate as the oxidizer mass flux increased. However, the nano-sized particles decrease the regression rate as the oxidizer mass flux is increased.

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Fabrication of 316L Stainless Steel having Low Contact Resistance for PEMFC Separator using Powder Metallurgy (분말야금법에 의한 고분자전해질 연료전지 분리판용 저접촉저항 316L 스테인리스강 복합소재 제조)

  • Choi, Joon Hwan;Kim, Myong-Hwan;Kim, Yong-Jin
    • Korean Journal of Metals and Materials
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    • v.46 no.12
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    • pp.817-822
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    • 2008
  • Metal matrix composite (MMC) materials having low electrical contact resistance based on 316L stainless steel (STS) matrix alloy with $ZrB_2$ particles were fabricated for PEMFC (Polymer Electrolyte Membrane Fuel Cell) separator by powder metallurgy (PM). The effects of the boride particle addition into the matrix alloy on microstructure, surface morphology, and interfacial contact resistance (ICR) between the samples and gas diffusion layer (GDL) were investigated. Both conventional and PM 316L STS samples showed high ICR due to the existence of non-conductive passive film on the alloy surface. The addition of the boride particles, however, remarkably reduced ICR of the samples. SEM observation revealed that the boride particles were protruded out of the matrix surface and particle density existing on the surface increased with increasing the boride content, causing increase of the total contact area between the conductive particles and GDL. ICR of the samples also decreased with increasing the boride content resulted from the increased contact area.

An experimental study on pool sloshing behavior with solid particles

  • Cheng, Songbai;Li, Shuo;Li, Kejia;Zhang, Ting
    • Nuclear Engineering and Technology
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    • v.51 no.1
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    • pp.73-83
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    • 2019
  • It is important to clarify the mechanisms of molten-fuel-pool sloshing behavior that might be encountered during a core disruptive accident of sodium-cooled fast reactors. In this study, motivated by acquiring some evidence for understanding the characteristics of this behavior at more realistic conditions, a number of experiments are newly performed by injecting nitrogen gas into a water pool with the accumulation of solid particles. To achieve comprehensive understanding, various parameters including particle bed height, particle size, density, shape, gas pressure along with the gas-injection duration, were employed. It is found that due to the different interaction mechanisms between solid particles and the gas bubble injected, three kinds of regimes, termed respectively as the bubble-impulsion dominant regime, the transitional regime and the bed-inertia dominant regime, could be identified. The performed analyses also suggest that under present conditions, all our experimental parameters employed can have noticeable impact on the regime transition and resultant sloshing intensity (e.g. maximum elevation of water level at pool peripheries). Knowledge and fundamental data from this work will be used for the future verifications of fast reactor severe accident codes in China.

Electrochemical Catalysts Test for Nano Pt Particles on Carbon Support Synthesized by a Polyol Process Parameter Control (폴리올 공정 제어에 의한 탄소기반 나노 Pt 촉매 담지 특성 평가)

  • Chae Lin Moon;Jin Woo Bae;Soon Mok Choi
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.36 no.2
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    • pp.164-169
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    • 2023
  • Nano Pt particles were dispersed on carbon-based supports by a polyol process for a catalyst application in a polymer electrolyte fuel cell. We tried to optimize the effect of pH on the electrostatic forces between the support and the Pt colloids. We investigated the relationship among the surface charges on the carbon support, the solution pH, and the concentration of a glycolate, and the Pt particle size. The produced catalyst with nano Pt particles on the support was evaluated by the long-term cyclic voltammetry (CV) performance test and compared with the results from a commercial catalyst. Our experimental results reveal that the pH-control can modify the particle size distribution and the dispersion of the nano Pt particles. This resulted in a cost-effective method for the synthesis of highly Pt loaded Pt/C catalysts for fuel cells better than a commercial catalyst system.

Combustion and Performance Efficiency of Boron Carbide Fuel in Solid Fuel Ramjet (고체 램제트 추진기관에서 보론 카바이드 연료의 연소, 성능 특성)

  • Lee, Tae-Ho
    • Journal of the Korean Society of Propulsion Engineers
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    • v.8 no.2
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    • pp.95-101
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    • 2004
  • An experimental investigation was conducted to investigate the effects of the equivalence ratio and air mass flux on the combustion efficiency in a solid fuel ramjet used fuel grains which were highly loaded with boron carbide. Combustion efficiency increased with increasing equivalence ratio (grain length), and decreasing air mass flux. Higher inlet air temperature produced higher combustion efficiencies, apparently the result of enhanced combustion of the larger boron particles those burn in a diffusion controlled regime. Short grains which considered primarily of the recirculation region produced larger particles and lower combustion efficiencies. The result of the normalized combustion efficiency increased with inlet air temperatures coincident with the result of the Brayton cycle thermal and the total efficiency relating to the heat input.

Simulation Study on the Effects of Heating Rate and Particle Size Distribution for the Formation of the Agglomerate During CWM Combustion (CWM 연료의 연소시 입자 가열속도와 입자 크기가 CWM 응집물 형성에 미치는 영향에 관한 전산모사 연구)

  • Kim, Soo-Ho;Kim, Young-Hwan;Hwang, Kap-Sung;Hong, Song-Sun
    • Applied Chemistry for Engineering
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    • v.9 no.3
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    • pp.364-371
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    • 1998
  • A theoretical model of particle agglomeration was developed to investigate the adhesive force between contiguous coal particles in CWM agglomerate. While heating bituminous coal to about $400^{\circ}C$ or above, the transient occurrence of plastic behavior of coal particles can be observed. The adhesive force in the process of agglomeration of coal particles was found to be proportional to the duration of plasticity of the particles. In the research, how the heating rate and the particle size distribution of CWM fuel influenced the formation of the agglomerate in CWM fuel at the heat-up stage was investigated by the model of particle agglomeration. Simulation program used to this experiment was RKG method and was programmed by Fortran. It was represented that by the model of particle agglomeration, the adhesive force in the process of the particle agglomeration in CWM fuel was inversely proportional to the heating rate but proportional to particle size.

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A Study on Combustion Characteristics of Paraffin Wax Fuel for Content of Micron-sized Aluminum Particles (마이크로 알루미늄 입자 함유량에 따른 파라핀 연료의 연소 특성 연구)

  • Park, Younghoon;Ryu, Sunghoon;Han, Seongjoo;Moon, Heejang;Kim, Jinkon;Kim, Junhyung;Ko, Seungwon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2017.05a
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    • pp.489-494
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    • 2017
  • This paper describes the combustion characteristics of aluminized paraffin fuel on the contents of micron-sized aluminum particles with nominal diameters of $8{\mu}m$. Aluminized paraffin fuels with mixture ratio of aluminum 0 wt%, 5 wt% and 10 wt% as fuel and GOx(Gaseous Oxygen) as oxidizer were used to perform the experiments. The experimental investigations were performed on the regression rate, the chamber pressure and the combustion efficiency. Increasing a content of micron-sized aluminum particles, the results of regression rate, chamber pressure and combustion efficiency show minor increase compared to those without particles.

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Analysis of Soot Particle Morphology Using Rayleigh Debye Gans Scattering Theory (RDG 산란 이론을 이용한 그을음 탄소 입자의 형상 분석)

  • Seo, Hyoungseock;Kim, Kibum
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.17 no.9
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    • pp.641-646
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    • 2016
  • Soot particles generated by fossil fuel combustion normally have fractal morphology with aggregates consisting of small spherical particles. Thus, Rayleigh or Mie elastic light scattering theory is not feasible for determining the fractal properties of soot aggregates. This paper describes a detailed process for applying Rayleigh-Debye Gans (RDG) scattering theory to effectively extract the morphological properties of any nano-scale particles. The fractal geometry of soot aggregates produced from an isooctane diffusion flame was observed using ex situ transmission electron microscopy (TEM) after thermophoretic sampling. RDG scattering theory was then used to analyze their fractal morphology, and various properties were calculated, such as the diameter of individual soot particles, number density, and volume fraction. The results show indiscernible changes during the soot growth process, but a distinct decreasing trend was observed in the soot oxidation process. The fractal dimension of the soot aggregates was determined to be around 1.82, which is in good agreement with that produced for other types of fuel. Thus, it can be concluded that the value of the fractal dimension is independent of the fuel type.

A Study on characteristics of AUC Powder Prepared with the Waste AC Solution (폐 AC용액으로부터 제조된 AUC분말의 특성에 대한 연구)

  • 정경채;김태준;최종현;박진호
    • Journal of the Korean Ceramic Society
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    • v.33 no.3
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    • pp.332-338
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    • 1996
  • This study was investigated on the recycle feasibility of the waste AC(Ammonium Carbonate) solution produ-ced in a commercial AUC(Ammonium Uranyl Carbonate) conversion plant. AUC particles were produced with the AC solution which was prepared with AC solid-agent instead of ammonia and carbon-dioxide gases. As the results particles of monoclinic shapes has been obtained regardless of the pH change if the carbonate concentration is sufficient in the mother liquore. Also a lot of twinned or aggregated particles were formed in case of the increase of pH in the reaction system but not affected in the change of temperature. Consequen-tly the characteristics of the particles which converted for AUC were produced withAC solution to UO2, particles specific surface area shape sintered density and others were similar to that of the particles which were produced with gases only when the pellets are fabricated in the nuclear fuel manufacturing process So the waste AC solution which is produced in the commercial AUC conversion plant is possible to recycle.

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