• Title/Summary/Keyword: Orifice Diameter Ratio

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A Study for Energy Separation of Vortex Tube Using Air Supply System(II) - the effect of surface insulation - (공기공급 시스템에 적응되는 Vortex Tube의 에너지 분리특성에 관한 연구(II) -표면의 단열효과에 따른 영향-)

  • 방창훈;추홍록;유갑종
    • Journal of the Korean Society of Safety
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    • v.14 no.1
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    • pp.3-9
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    • 1999
  • The vortex tube is a simple device which splits a compressed gas stream into a cold stream and a hot stream without any chemical reactions. Recently, vortex tube is widely used to local cooler of industrial equipments and air supply system. In this study, the insulation effect of surface on the efficiency of vortex tube was performed experimentally. The experiment is carried out for nozzle area ratio of 0.194, diameter ratio of cold end orifice of 0.6 and input pressure ranging from 0.2Mpa to 0.5Mpa. The purpose of this study is focused on the effect of surface insulation of vortex tube with the variation of cold air mass flow ratio. The results indicate that the temperature difference of cold and hot air are higher about 12% and 30% than that of not insulated vortex tube respectively. Furthermore, for the insulated vortex tube, the similarity relation for the prediction of cold end temperature as the function of cold air mass flow ratio and input pressure is obtained.

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Risk evaluation of EVA dust with oxidizer by a pressure vessel (압력용기시험에 의한 EVA분진의 혼촉 위험성 평가)

  • 이창우;김정환;현성호
    • Fire Science and Engineering
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    • v.13 no.4
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    • pp.7-12
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    • 1999
  • Thermal properties of EVA dust and its risks of coexisting with oxidizer were investigated by a pressure vessel. The decomposition of EVA dust with temperature using DSC and the weight loss with temperature using TGA were also investigated to find the thermal hazard of EVA dust. Using the pressure vessel which can estimate ignition and explosion of EVA dust coexisting with oxidizer by bursting of a rupture disc, many experiments have been conducted by varying the orifice diameter, heating rate, the weight ratio of the sample coexisting with oxidizer, and the species of oxidizer. According to the results of the thermal analysis of EVA dust, a little change of the decomposition initiation temperature with the heating rate could be found and the decomposition temperature zone of EVA dust was 250 to 50$0^{\circ}C$. The risk of EVA dust coexisting with oxidizer was increased as the orifice diameter was decreased. On the other hand, it was increased as the heating rate and the weight ratio of the sample coexisting with oxidizer were increased. In addition, the risk of EVA dust coexisting with oxidizer was affected by the decomposition temperature of the sample and oxidizer, respectively, at slow heating rate, but it was affected by the oxygen weight percent of oxidizer at fast heating rate.

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An Experimental Study on the Characteristics of Temperature Separation for the Formal Change of Counterflow Type Vortex Tube (대향류형 보텍스 튜브에서의 형상 변화에 따른 온도 분리에 관한 실험적 연구(I))

  • 황승식;전운학;김종철;이희상
    • Transactions of the Korean Society of Automotive Engineers
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    • v.9 no.1
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    • pp.84-93
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    • 2001
  • The aim of this study is to provide fundamental informations that make it possible to use a cool stream and a hot stream simultaneously. We changed the pressure of compressed air that flows into a tube, the inner diameter of orifice that a cold stream exits, and the mass flow rate ratio. And in each case, we measured the temperature of a cold stream and a hot stream in each exit of a tube. Also we measured the axial temperature distribution and the radial temperature distribution in internal space of a tube. From the study, following conclusive remarks can be made. Average flow rate that flows into a tube is in proportion to square root of inlet pressure. As inlet pressure increases axial and radial temperature distribution in the inner space of vortex-tube increase. As mass flow rate ratio change, separation point moves.

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The Effect of Valve Geometry Variation on Injection Characteristics of Injection Valve for Marine Diesel Engines (선박디젤기관용 분사밸브의 형상변화가 분사특성에 미치는 영향에 관한 계산적 고찰)

  • Park, K.;Kim, S.Y.;Choi, C.W.
    • Journal of ILASS-Korea
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    • v.10 no.1
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    • pp.24-34
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    • 2005
  • Injection technology is one of the important technologies in a diesel engine. Many studies have done on the injection system. In this study, the fuel chamber geometry, the orifice ratio and the needle lift of the injection valve for a marine diesel engine are varied, and simulated. The result shows that the nozzle hole size has influence on the rail pressure and injection duration sensitively. The decrease of the static pressure at the nozzle hole entrance and the increase of the dynamic pressure on the outlet surface are occurred with the increase of the nozzle hole diameter. The highest dynamic pressure of the outlet was occurred at the needle lift of 0.4mm and the nozzle hole diameter of 0.328mm in this test nozzle.

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Microencapsulation of Anchovy Oil by Sodium Alginate (알긴산소다를 이용한 멸치어유의 미세캡슐화)

  • 임상빈;좌미경
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.28 no.4
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    • pp.890-894
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    • 1999
  • Microencapsulation of anchovy oil as a core material in sodium alginate as a wall material was inves tigated. Microencapsulation was accomplished by injecting an oil/water emulsion, consisting of a mixture of liquefied sodium alginate and emulsifier, under high pressure through an orifice submerged in a calcium lactate solution. Microcapsules suspended in a dispersion fluid were observed under a fluorescence mi croscope to verify the presence of the capsules and to note coalescence or degradation of the capsules. Optimum conditions for microencapsulation of anchovy oil were obtained when 1.0% aqueous solution of sodium alginate contained 3% of a 1:1 ratio of ESPR 25(polyglycerine+polylinoleate) and TW 20(sorbitan laurate+ethylene oxide) as an emulsifier in terms of capsule size and size distribution, and emulsion stability. The airless sprayer produced microcapsules with a diameter between 15.9 and 73.9 m with different concentration of a wall material. The optimum mixing ratio of wall material to core material was 90:10(wt/wt). 0.2% calcium lactate was appropriate as a dispersion fluid.

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A Study of mixing characteristics of unlike impinging streams doublet injector (이유체 충돌 분사기의 혼합특성에 관한 연구)

  • Han, Jae-Seob;Kim, Seon-Jin;Kim, Yoo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.4 no.4
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    • pp.36-41
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    • 2000
  • Mixing characteristics of unlike impinging streams double injectors have a great effect on combustion stability and combustion efficiency for liquid rocket engine. In this study a cold test was carried out, using water and TCE as simulants, in order to examine the effect of design parameters such as impingement angle, orifice diameter ratio and momentum ratio on the mass distribution and mixing quality.

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Energy Separation Characteristics of Single Hole Vortex Generator (단일 유로를 갖는 와류발생기의 에너지분리 특성)

  • Yu, Gap-Jong;Jang, Jun-Yeong;Choe, In-Su
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.25 no.8
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    • pp.1005-1012
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    • 2001
  • When vortex tubes are applied to enhance the coefficient of performance of refrigeration system, the smaller one is preferable. However, the existing vortex generator with a nozzle hole diameter of 0.5mm was not suitable due to chocking of the nozzle hole. Therefore, experimental investigation was made to find an appropriate geometry of vortex generator, which could give a comparable effect of energy separation to commercial ones without chocking problem. The tested vortex generators were tangential and spiral types, which had single inducing channel with larger cross-sectional area than that of conventional multi-hole ones. The experimental result showed that the performance of the spiral type was better than that of the tangential one. As a small size of spiral one, the diameter of cold-end orifice is proposed to an half of tube diameter for the application to refrigeration system, while cold mass fraction ratio is 0.5∼0.6 for a desirable operation.

Disintegration and Spreading Behavior of the Spray emanating from a Liquid-thruster Injector (액체추력기 인젝터로부터 발생하는 분무의 분열 및 확산 거동)

  • Kim, Jin-Seok;Jung, Hun;Kim, Jeong-Soo;Kim, Sung-Cho;Park, Jeong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.113-116
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    • 2008
  • Pseudo-3D Spatial distribution of spray droplets is investigated by using Dual-mode Phase Doppler Anemometry (DPDA) in order to examine the disintegration and spreading behavior of spray exiting from liquid-thruster injector. Spray injected from nozzle orifice with length-to-diameter ratio $(L/d_o)$ of 1.67 and at the injection pressure of 27.6 bar is aligned to the vertical. Vertical and horizontal mean velocities of droplets, Arithmetic Mean Diameter (AMD), Sauter Mean Diameter (SMD), and volumetric flux decrease as droplets travel from center/upstream toward outer region/downstream of spray.

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A Study on High-Temperature Fuel Injection Characteristics through Swirl Injectors (스월 인젝터를 통한 고온 연료의 분사특성 연구)

  • Lee, Hyung Ju;Choi, Hojin;Kim, Ildoo;Hwang, Ki-Young
    • Journal of the Korean Society of Propulsion Engineers
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    • v.17 no.6
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    • pp.11-19
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    • 2013
  • An experimental study was conducted to investigate fuel injection characteristics through swirl injectors when the fuel was heated to very high temperature conditions. Three swirl injectors with different orifice diameters and swirler geometries were used to measure the flow coefficient (${\alpha}$) for the injection pressure ranges between 3 and 10 bar and the fuel temperature from 50 to $270^{\circ}C$. The results showed that the variation characteristics of ${\alpha}$ with respect to cavitation number ($K_c$) were highly dependent on both the orifice diameter and the swirler geometry. In addition, the characteristics of ${\alpha}$ variation with respect to AR, the area ratio of the flow through the swirler and the orifice, has revealed that the effect of boiling is retarded but the slope of decreasing ${\alpha}$ after the boiling effect is present tumbles as AR increases.

Characteristics of Air-assist Spray Injected into Cross-flow with Various Gas-liquid Ratio (횡단유동으로 분사하는 이유체노즐의 기체-액체비에 따른 분무특성)

  • Cho, Woo-Jin;Lee, In-Chul;Lee, Bong-Su;Lee, Hyo-Won;Koo, Ja-Ye
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.11a
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    • pp.159-162
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    • 2007
  • The characteristic of air-assist spray injected into subsonic crossflow were studied experimentally. External-mixing air assist injector of Orifice nozzle with L/d of 3 were tested with various air-liquid ratio. Shadowgraph photography was performed for spray visualization and trajectory of spray measurements. The detailed spray structure was characterized in terms of SMD, velocity, and volume flux, using PDPA. Experimental results indicate that penetration length was increased and spray distribution was accelerated by increasing air-liquid ratio.

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