• Title/Summary/Keyword: Water atomization

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Fabrication and Magnetic Properties of A New Fe-based Amorphous Compound Powder Cores

  • Xiangyue, Wang;Feng, Guo;Caowei, Lu;Zhichao, Lu;Deren, Li;Shaoxiong, Zhou
    • Journal of Magnetics
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    • v.16 no.3
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    • pp.318-321
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    • 2011
  • A new Fe-based amorphous compound powder was prepared from Fe-Si-B amorphous powder by crushing amorphous ribbons as the first magnetic component and Fe-Cr-Mo metallic glassy powder by water atomization as the second magnetic component. Subsequently by adding organic and inorganic binders to the compound powder and cold pressing, the new Fe-based amorphous compound powder cores were fabricated. This new Fe-based amorphous compound powder cores combine the superior DC-Bias properties and the excellent core loss. The core loss of 500 kW/$m^3$ at $B_m$ = 0.1T and f = 100 kHz was obtained When the mass ratio of FeSiB/FeCrMo equals 3:2, and meanwhile the DC-bias properties of the new Fe-based amorphous compound powder cores just decreased by 10% compared with that of the FeSiB powder cores. In addition, with the increasing of the content of the FeCrMo metallic glassy powder, the core loss tends to decrease.

Fabrication and Magnetic Process of 13Cr-1.5Nb-Fe Stainless Sensors (13Cr-1.5Nb-Fe 스텐레스 센서재료의 제조 및 연자기특성)

  • 윤성호;김택기;조용수
    • Journal of the Korean Magnetics Society
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    • v.8 no.3
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    • pp.125-130
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    • 1998
  • 13Cr-1.5Nb-Fe alloy powder was fabricated by water atomization method, and ring-shape specimen of this composition was fabricated by oil press, and then sintered in the vacuum furnace. Powder shape, size distribution, composition (C, N, O, S) analysis and saturation magnetization of as-prepared 13Cr-1.5Nb-Fe alloy powder were investigated. Ac permeability and power loss was measured after forming and sintering process. Saturation magnetization and contents of oxygen of the alloy powder is160 emu/g and about 6000 ppm, respectively. 50 % volume fraction indicate particle size of 70$\mu$m. The ac permeability of sintered specimen increases with increasing sintering temperature and forming pressure. The power loss is 107 W/cc at sintering temperature of 1200 $^{\circ}C$, 12 ton/$\textrm{cm}^2$ forming pressure, and 20 KHz. It is the lowest among the prepared specimen.

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Measurement of Breakup Length of Viscous Liquid Jet in Stagnant Air (정지공기중 점성유체 분류의 분열길이 측정)

  • Rhim, Jung-Hyun;Ryu, Keun-Young;Lim, Sung-Bin;No, Soo-Young
    • Journal of ILASS-Korea
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    • v.3 no.4
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    • pp.1-7
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    • 1998
  • The measurement of breakup length of viscous liquid jet in stagnant air was conducted by a 3CCD digital video camera. The nozzle diameters of 4, 6, 8mm with L/d=50 were selected and the dynamic viscosity of viscous liquid made of glycerine and water was in the range of $1.061\times10^{-6}m^2/s$ to $4.935\times10^{-5}m^2/s$. The critical velocity is decreased and the breakup length is increased with the increase of nozzle diameter at the same dynamic viscosity of liquid. At the same nozzle diameter, the breakup length and the critical velocity are both increased with the increase of dynamic viscosity of liquid. It is found in the theoretical analysis that the initial disturbance level is the main cause of occurrance of critical Reynolds number in the stability curve. The comparison of experimental critical Reynolds number and the empirical correlation by Tanasawa and Toyota reveals the relatively good agreement.

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A Study on the Fluid Mixing Analysis for Proving Shell Wall Thinning of a Feedwater Heater (급수가열기 동체 감육 현상 규명을 위한 유동해석 연구)

  • Kim, Kyung-Hoon;Hwang, Kyeong-Mo;Kim, Sang-Nyung
    • Journal of ILASS-Korea
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    • v.9 no.4
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    • pp.24-30
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    • 2004
  • Feedwater flowing tube side of number 5 high pressure feedwatrr heaters was heated by extracting steam from high pressure turbine and draining water from moisture separators and number 6 high pressure feedwater heaters and supplied into steam generators. Because the extracting steam from the high pressure turbine is two phase fluid of high temperature, high pressure, and high speed and flows to inverse direction after impinging to impingement baffle. the shell wall of the number 5 high pressure feedwater heater may be affected by flow accelerated corrosion. On May 14, 1999, Point Beach Nuclear Plant (PBNP) with operating at full power experienced a steam leak from rupture of shell side of number 4B feedwater heater. Also, d domestic nuclear power plant experienced a severe wall thinning of shell side of number 5A and 5B feedwater heaters. This paper describes the fluid mixing analysis study using PHOENICS code in order to get at the root of the shell wall thinning of the feedwater heaters. The sections included in the fluid mixing analysis model are around the number 5h feedwater heater shell including the extracting pipeline. To identify the relation between the local velocities and wall thinning. the local velocities according to the analysis results were compared with the distribution of the shell wall thickness by ultrasonic test.

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Feasibility Study of Using Wood Pyrolysis Oil in a Diesel Engine (목질 열분해유의 디젤 엔진 적용성 연구)

  • Lee, Seok-Hwan;Park, Jun-Hyuk;Lim, Gi-Hun;Choi, Young;Woo, Se-Jong;Kang, Kern-Yong
    • Journal of ILASS-Korea
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    • v.16 no.3
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    • pp.152-158
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    • 2011
  • Fast pyrolysis of biomass is one of the most promising technologies for converting biomass to liquid fuels. The pyrolysis oil, also known as the bio crude oil (BCO), have been regarded as an alternative fuel for petroleum fuels to be used in diesel engine. However, the use of BCO in diesel engine requires modifications due to low energy density, high water contents, low acidity, and high viscosity of the BCO. One of the easiest way to adopt BCO to diesel engine without modifications is the use of BCO/diesel emulsions. In this study, a diesel engine operated with diesel, bio diesel (BD), and BCO/diesel emulsion was experimentally investigated. Performance and emission characteristics of a diesel engine fuelled by BCO/diesel emulsion were examined. Results showed that stable engine operation was possible with emulsion and engine output power was comparable to diesel and bio diesel operation. Long term validation of adopting BCO in diesel engine is still needed because the oil is acid, with consequent problems of corrosion especially in the injection system.

Atomizing Characteristics of Coaxial Porous Injectors (다공성재를 이용한 동축형 분사기의 미립화특성)

  • Kim, Do-Hun;Shin, Jeung-Hwan;Lee, In-Chul;Koo, Ja-Ye
    • Journal of ILASS-Korea
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    • v.17 no.1
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    • pp.35-44
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    • 2012
  • To improve the mixing and atomizing performance at the center region of the conventional coaxial shear injector spray, the concept of a coaxial porous injector was invented. This novel injection concept for liquid rocket engines utilizes the Taylor-Culick flow in the cylindrical porous tube. The 2-dimensional injector, which can be converted in three injection configurations, was fabricated, and several cold flow tests using water-air simulant propellant was performed. The hydraulic characteristics and the effects of a gas flow condition on the spray pattern and the Sauter mean diameter (SMD) was analyzed for each configuration. The atomizing mechanism of coaxial porous injector was different with the coaxial shear injector, and it was explained by the momentum of the gas jet, which is injected normally against the center liquid column, and by the secondary disintegration at the wavy interface of liquid jet, which was generated at the recessed region. The SMD of 2D coaxial porous injector, which has higher gas momentum, was measured and it shows better atomizing performance at the center and outer side of spray than the 2D coaxial shear injector.

Performance and Emission Studies in a DI Diesel Engine Fuelled with Diesel-Pyrolysis Oil Emulsion (디젤-열분해유 유상액을 사용하는 직접분사식 디젤 엔진의 엔진성능 및 배기특성에 관한 연구)

  • Lee, Seokhwan;Kim, Hoseung;Kim, Taeyoung;Woo, Sejong;Kang, Kernyong
    • Journal of ILASS-Korea
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    • v.19 no.2
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    • pp.55-63
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    • 2014
  • Pyrolysis oil (PO), also known as Bio crude oil (BCO), has the potential to displace significant amounts of fuels that are currently derived from petroleum sources. PO has been regarded as an alternative fuel for petroleum fuels to be used in diesel engine. However, the use of PO in a diesel engine requires modifications due to low energy density, high water contents, low acidity, and high viscosity of the PO. One of the easiest way to adopt PO to diesel engine without modifications is emulsification of PO with the fuels that has higher cetane number. However, PO that has high amount of polar chemicals is immiscible with non polar hydrocarbons of diesel. Thus, to stabilize a homogeneous phase of diesel-PO blends, a proper surfactant should be used. In this study, a DI diesel engine operated with diesel and diesel-PO emulsions was experimentally investigated. Performance and gaseous & particle emission characteristics of a diesel engine fuelled by diesel-PO emulsions were examined. Results showed that stable engine operation was possible with the emulsions and engine output power was comparable to diesel operation.

A Study on the Droplet Behavior Impacting on an Orifice (오리피스와 충돌하는 액적 거동에 관한 연구)

  • D.H., Seo;D.J., Lee;H.B., Lee;B.S., Kang
    • Journal of ILASS-Korea
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    • v.27 no.4
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    • pp.188-194
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    • 2022
  • In this study, the behavior of water droplet impacting on a thin horizontal orifice was investigated. The impact behavior modes, transition velocities and diameters of daughter droplets were analyzed by changing the droplet velocity, orifice diameter and orifice thickness. Four typical modes of impacting droplet on an orifice were observed. The single-droplet and double-droplet transition velocities increased with increasing the orifice thickness and decreased with increasing the orifice diameter. On the other hand, the multi-droplet transition velocity decreased and then increased as the orifice diameter increased. At thin orifice thickness, the single droplet diameter approximated the orifice diameter, and increasing the orifice thickness produced a droplet larger than the orifice diameter. In the case of double droplet mode, the diameter of the first droplet showed a similar tendency like the single droplet mode, but the diameter of the second droplet was smaller than that of the first droplet, and the difference between them was affected more by the orifice thickness.

Spray Characteristics of Water-Gel Propellant by Impinging Injector (Water-Gel 모사 추진제의 충돌 분무 특성 연구)

  • Hwang, Tae-Jin;Lee, In-Chul;Kim, Sang-Sun;Koo, Ja-Ye
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.11a
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    • pp.11-14
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    • 2009
  • The implementation of gelled propellants systems offers high performance, thrust-control, energy management of propulsion, storability, and high density impulse of solid propulsion. Present study focused on the spray behavior of liquid sheets formed by impinging jets of non-Newtonian liquids which are mixed by Carbopol 941 0.5%wt. The results are then compared with experiments conducted on spray images formed by impinging jets concerning with air-blast effect at center orifice. When gel propellants are injected by doublet impinging jets at low pressure, closed rim pattern shape appeared. As increasing air mass flow rate(decreasing GLR), spray breakup and atomization phenomenon better improved and spray structure instabilities for the effect of air-blast are also increased.

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Performance and Emission Characteristics of a Diesel Engine Operated with Wood Pyrolysis Oil (목질 열분해유를 사용하는 디젤엔진의 성능 및 배기특성에 관한 연구)

  • Lee, Seok-Hwan;Park, Jun-Hyuk;Choi, Young;Woo, Se-Jong;Kang, Kern-Yong
    • Transactions of the Korean Society of Automotive Engineers
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    • v.20 no.5
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    • pp.102-112
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    • 2012
  • The vast stores of biomass available in the worldwide have the potential to displace significant amounts of fuels that are currently derived from petroleum sources. Fast pyrolysis of biomass is one of possible paths by which we can convert biomass to higher value products. The wood pyrolysis oil (WPO), also known as the bio crude oil (BCO), have been regarded as an alternative fuel for petroleum fuels to be used in diesel engine. However, the use of BCO in a diesel engine requires modifications due to low energy density, high water contents, low acidity, and high viscosity of the BCO. One of the easiest way to adopt BCO to diesel engine without modifications is emulsification of BCO with diesel and bio diesel. In this study, a diesel engine operated with diesel, bio diesel (BD), BCO/diesel, BCO/bio diesel emulsions was experimentally investigated. Performance and gaseous & particle emission characteristics of a diesel engine fuelled by BCO emulsions were examined. Results showed that stable engine operation was possible with emulsions and engine output power was comparable to diesel and bio diesel operation. However, in case of BCO/diesel emulsion operation, THC & CO emissions were increased due to the increased ignition delay and poor spray atomization and NOx & Soot were decreased due to the water and oxygen in the fuel. Long term validation of adopting BCO in diesel engine is still needed because the oil is acid, with consequent problems of corrosion and clogging especially in the injection system.