• Title/Summary/Keyword: Spray method

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Synthesis and Characterization of W Composite Powder with La2O3-Y2O3 Nano-dispersoids by Ultrasonic Spray Pyrolysis

  • Youn Ji Heo;Eui Seon Lee;Jeong Hyun Kim;Young-In Lee;Young-Keun Jeong;Sung-Tag Oh
    • Archives of Metallurgy and Materials
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    • v.67 no.4
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    • pp.1507-1510
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    • 2022
  • An optimum route to synthesis the W-based composite powders with homogeneous dispersion of oxide nanoparticles was investigated. The La2O3 dispersed W powder was synthesized by ultrasonic spray pyrolysis using ammonium metatungstate hydrate and lanthanum nitrate. The dispersion of Y2O3 nanoparticles in W- La2O3 powder was carried out by a polymer addition solution method using yttrium nitrate. XPS and TEM analyses for the composite powder showed that the nano-sized La2O3 and Y2O3 particles were well distributed in W powder. This study suggests that the combination processing of ultrasonic spray pyrolysis and polymeric additive solution is a promising way to synthesis W-based composite powders.

A Basic Study of the Behavior Characteristics of Diesel Spray and Natural-gas Jet (디젤 분무와 천연 가스 분류의 거동 특성에 관한 기초 연구)

  • Yeom, J.K.;Kim, M.C.
    • Journal of Power System Engineering
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    • v.13 no.6
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    • pp.13-21
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    • 2009
  • This basic study is required to examine spray or jet behavior depending on fuel phase. In this study, analyses of diesel fuel(n-Tridecane, C13H28) spray and natural gas fuel(Methane, CH4) jet under high temperature and pressure are performed by a general-purpose program, ANSYS CFX release 11.0, and the results of these are compared with experimental results of diesel fuel spray using the exciplex fluorescence method. The simulation results of diesel spray is analyzed by using the combination of Large-Eddy Simulation(LES) and Lagrangian Particle Tracking(LPT) and of a natural gas jet is analyzed by using Multi-Component Model(MCM). There are two study variables considered, that is, ambient pressure and injection pressure. In a macroscopic analysis, the higher ambient pressure is, the shorter spray or jet tip penetration is at each time after start of injection. And the higher injection pressure is, the longer spray or jet tip penetration is at each time after start of injection. When liquid fuel is injected, droplets of the fuel need some time to evaporate. However, when natural gas fuel is injected, the fuel does not need time to evaporate. Gas fuel consists of minute particles. Therefore, the gas fuel is mixed with the ambient gas more quickly at the initial time of injection than the liquid fuel is done. The experimental results also validate the usefulness of this analysis.

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The Spray Characteristics of Swirl and Slit Injector to DISI Engine Using LIEF and Mie-scattering Method (LIEE와 Mie 산란 방법을 이용한 직분식 가솔린 엔진의 스월 및 슬릿 인젝터의 분무 특성)

  • Lee Kihyung;Hwang Kyumin;Lee Changhee
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.29 no.3 s.234
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    • pp.356-367
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    • 2005
  • The spray characteristics of DISI injector have a great role in gasoline engine efficiency and emission. Thus, many researchers have studied to investigate the spray characteristics of swirl and slit injectors that are used in a DISI engine. In this study, we tried to provide spray parameters, which affect on the spray characteristics such as injection pressure, ambient pressure and ambient temperature. In addition, we calculated tbandtc to investigate the break up mechanism of test injectors and obtained Cv to evaluate the spray characteristics. As the ambient pressure increases in case of slit injector, Cv decreases. The laser-induced exciplex fluorescence (LIEF) technique, which is based on spectrally resolved two-color fluorescent emissions, has applied to measure the liquid and vapor phases for on evaporating spray simultaneously. The TMPD/naphthalene proposed by Melton is used as a dophant to detect exciplex signal. The temporal and spatial distribution of liquid and vapor phases during the mixture formation process was measured by this technique. In the LIEF technique, the vapor phase is detected by the monomer fluorescence while the liquid phase is tracked by the exciplex fluorescence. From this experiment, we found that the spray area of the vapor phase is increased with elapsed time after injection and the area of liquid is decreased when the ambient pressure is 0.1MPa. However, the area tends to increase until the end of injection when the ambient pressure is 1.0MPa.

Numerical Simulation of Swirl Effect on the Flow Fields and Spray Characteristics in Direct Injection Engine (적접분사 엔진의 유동장 및 분무특성에 미치는 선회비의 영향에 대한 수치해석적 연구)

  • Hong, K.B.;Kim, H.S.;Yang, H.C.;Ryou, H.S.
    • Journal of the Korean Society of Safety
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    • v.10 no.3
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    • pp.120-129
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    • 1995
  • Since the rate and completeness of combustion in direct injection engines were controlled by the characteristics of gas flow fields and sprays, an understanding of those was essential to the design of the direct injection engines. In this study the numerical simulations of swirl effects on the characteristics of gas flow fields and sprays were performed using the spray model that could predict the interactions between gas fields and spray droplets. The governing equations were discretized by the finite volume method and the modified k- e model which included the compressibility effects due to the compression/expansion of piston was used. The results of numerical calculation of the spray characteristics in the quiescent environment were compared with the experimental data. There were good agreements between the results of calculation and the experimental data, except in the early stages of spray. In the motoring condition, the results showed that a substantial air entrainment into the spray volume was emerged and hence the squish motion was relatively unimportant during fuel injection periods. As the swirl ratio increased, the evaporation rate was increased due to the wide dispersion of the spray droplets and the strong interaction between spray droplets and gas fields.

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스프레이 법으로 제작된 MWCNT 투명전도막의 특성

  • Jang, Gyeong-Uk
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2009.11a
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    • pp.244-244
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    • 2009
  • Carbon nanotubes (CNTs) have excellent electrical, chemical stability, mechanical and thermal properties. In this paper, networks of Multi-walled carbon nanotube (MWCNT) materials were investigated as transparent electrode. Sensor films were fabricated by air spray method using the multi-walled CNTs solution on glass substrates. The film that was sprayed with the MWCNT dispersion for 60 sec, was 300nm thick. And the electric resistivity and the light transmittance rate are 2×102Ωcm and 60%, respectively.

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Synthesis of Spherical Fine PbTiO3 Particles by the Spray Pyrolysis Method Using Ultrasonic Vibrator (초음파 분무 열분해법에 의한 구형의 PbTiO3 미립자 제조)

  • 이서영;이동주;신건철
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.1 no.1
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    • pp.107-116
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    • 1991
  • Fine PbTiO3 Particles were synthesized from the Pb(NO3)2and TiO(NO3)2 solution by the spray pyrolysis method using the ultrasonic vibrator as a mist generator. The obtained particles were characterized. The mechanisms of particle formation were discussed in comparison with those if other particles, such as BaTiO3, ZnO2, ZnO ....., in the same spray pyrolysis process.

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A Study on the impact and solidification of the liquid metal droplet in the thermal spray deposition (용사 공정에서 용융 금속 액적의 충돌현상과 응고 과정 해석)

  • Ha, Eung-Ji;Kim, Woo-Seung
    • Proceedings of the KSME Conference
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    • 2001.06d
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    • pp.214-219
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    • 2001
  • In this study, numerical investigation has been performed on the spreading and solidification of a droplet impacting onto a solid substrate in the thermal spray process. The finite difference method with volume-of-fluid approach is used to analyze the free surface flow and the source-based enthalpy method is employed to model the latent heat release during the solidification. In this work, the numerical model is validated through the comparison of the present numerical result with experimental data available for the flat substrate.

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CdSe-sensitized Photoelectrochemical Solar Cell Prepared by Spray Pyrolysis Deposition Method

  • Im, Sang-Hyuk;Lee, Yong-Hui;Seok, Sang-Il
    • Journal of the Korean Electrochemical Society
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    • v.14 no.2
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    • pp.104-109
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    • 2011
  • We fabricated CdSe-sensitized photoelectrochemical solar cell by depositing CdSe nanoparticles on nanoporous TiO2 (np-TiO2) via spray pyrolysis deposition method. By adjusting the amount of CdSe-sensitizer deposited on np-TiO2, we can fabricate an efficient CdSe-sensitized solar cell (η = 3.0% under 1 sun irradiation) in polysulfide liquid electrolyte.

A Study on the Measurement Technique for Injection Rate and the Effects of the Nozzle Hole Number on Injection Characteristics (디젤 인젝터의 분사율 측정 기술과 분공수 변화가 분사특성에 미치는 영향에 관한 연구)

  • 이기형;정재우;이창식
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.3
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    • pp.1-7
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    • 2002
  • Recently, many researches for the improvement of DI diesel engines have been performed to reduce the fuel consumption and exhaust emissions. Among the various factors effect on combustion and emission in Dl diesel engines, one of the most important factors is the characteristics of the fuel spray. Accordingly, the investigation on the characteristics of spray is needed to analyze the diesel combustion exactly, In this study, the measurement technique fur injection rate using the Zeuch method was developed. In addition, the effects of nozzle hole number on the spray and flame were investigated by visualization experiment.

Response properties of alcohol gas sensors depositing MWNT-composites by spray method (MWNT를 스프레이 코팅한 가스센서의 알콜 가스 응답 특성)

  • Choi, Young-Min;Gam, Byung-Min;Lee, Ho-Jung;Kim, Seong-Jeen
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2008.11a
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    • pp.382-383
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    • 2008
  • In this paper we presented experimental results of a gas sensor utilizing multi-walled carbon nanotube (MWNT)composites for the alcohol detection which is useful to checking drinking and driving, for example. The MWNT-composites were deposited using spray method on PES substrates suitable for use in low-cost and flexible sensors. We observed the variation of conductance from the sensors exposed to alcohol vapors evaporated at 37C equal to the human body temperature to match real condition. As the result, the conductance was decreased with the increase of ethanol vol% diluted in water. The sensors showed good sensitivity and linearity.

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