• Title/Summary/Keyword: 충돌분무

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Analysis Surrounding Condition for the Design of a Novel Direct-injection Diesel engine Combustion System (새로운 형상의 디젤엔진 연소실 설계를 위한 주위조건의 분석)

  • ;T.F.Yeung
    • Transactions of the Korean Society of Automotive Engineers
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    • v.4 no.2
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    • pp.60-68
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    • 1996
  • 디젤 엔진의 분사연료를 연소실 내부에 마련된 작은 돌출부에 충돌시켜 액적을 작게 부수고 연료가 연소실 내부에 고루 분포할 수 있도록 하여 여러 가 지 엔진성능향상을 도모한 새로운 디젤 연소실 시스템이 최근 제시되고 있다. 이들 시스템은 피스톤 내부 혹은 엔진헤드 부위에 분사연료 충돌부를 두고 있는데, 여기에서는 이 새로운 시스템 개발에 있어 고려되어야 할 몇 가지 중요 요인들에 중점을 두어 분석하였다. 결과로서 분사압력, 사노즐크기, 주위공기 온도와 압력의 변화가 분무 평균입경과 분무연료의 분포에 미치는 영향을 제시하였다.

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A study on the effect of injection pressure and ambient pressure for the growth of impinging spray (충돌 분무의 성장에 미치는 분사압과 배압의 영향에 관한 연구)

  • Cha, Geon-Jong;Seo, Gyeong-Il;Kim, Deok-Jul
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.21 no.11
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    • pp.1458-1465
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    • 1997
  • This study investigated the effects of pressure on the growth of an impinging spray. We obtained the frozen images which were scattered by Nd ; YAG laser light (pulse width : 7 ns) using synchronization circuit made in the laboratory. For an impinging spray a growth of the penetration length was progressed with increase of the injection pressure but an ambient pressure restrained its growth. The effect of an ambient pressure on penetration was larger than that of an injection pressure. The pressure ratio had an effect on the penetration growth rate. The thickness growth rate depended on both the injection pressure and the ambient pressure compositively. A lower injection pressure or a higher ambient pressure was required for spatial distribution of impinging spray.

An Experimental Studies on Impingement Spray Characteristic in High Temperature and Pressure Chamber (고온고압용기에서 충돌분무 특성에 관한 실험적 연구)

  • 안병규;류호성;오은탁;송규근;정재연
    • Transactions of the Korean Society of Automotive Engineers
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    • v.10 no.3
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    • pp.36-43
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    • 2002
  • The characteristics of spray has much effect on performance and emissions for automobile, diesel engine, gas turbine and combustion engines. So spray behavior after impinging the wall is very important for prediction the engine performance. This studies examined about impingement spray considering ambient density(18,24,30kg/ms), temperature(293,473K), impingement angle(0,30,45°). The images of impingement spray were obtained by the high speed video camera. After that we analyzed impingement spray characteristics to use this images. In this experiment, we found that 1) The spray width is reduced by increasing the ambient gas density and temperature,2) The growth of downstream is increased by increasing the impingement angle.

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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Analysis of Spray Characteristics in w-shaped Diesel Engine Combustion Chamber with Impingement Lands (충돌부를 갖는 w-형 디젤엔진 연소실의 분무특성분석)

  • Park, K.;Park, D.S.;Kim, M.H.
    • Journal of ILASS-Korea
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    • v.1 no.4
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    • pp.40-45
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    • 1996
  • This Paper addresses to spray characteristics in w-shaped diesel engine combustion chamber which has impingement parts for 4 sprays injected from an injector. The two-dimensional shapes have been chosen to avoid the difficulties for analysing the spray dynamics in the real chamber. The simple shapes are reproduced with same geometries in vertical or horizontal sections through the impingement lands. The spray developments are visualized with a high speed drum camera and shadowgraphy optical system, and the droplet sizes are measured by Malvern system. The detailed discussions m made for the two different combustion chamber shapes, which are new w-shape using spray wall impaction and general w-shape. The results show that the spray characteristics of the new shape are superior to those of the general w-shape.

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Experimental investigation on impinging behaviors of non-Newtonian and viscous droplets through electrohydrodynamic atomization (전기수력학적 분무 방식을 통해 토출된 비뉴튼성 및 점성유체의 충돌 거동에 대한 실험적 연구)

  • Seo, Kyoung Duck;Hong, Jiwoo
    • Journal of the Korean Society of Visualization
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    • v.16 no.3
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    • pp.47-51
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    • 2018
  • The stable deposition of impinging droplets on non-wetting substrates is of great importance for numerous industrial and scientific applications such as coating techniques, inkjet printing, spray cooling of heated surfaces. In this work, we systematically investigate impinging behaviors of non-Newtonian and viscous droplets ejected by electrohydrodynamic atomization.

Numerical Study on the Effect of Anisotropic Turbulence Characteristics on the Droplet Behaviors for Impinging Sprays (충돌분무의 액적 거동에 미치는 비등방성 난류특성의 영향에 대한 수치해석 연구)

  • Ko G. H;Ryou H. S
    • Journal of computational fluids engineering
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    • v.8 no.4
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    • pp.6-15
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    • 2003
  • It is an aim of this study to perform extensive numerical study for analyzing the anisotropic turbulence effects on spatial and temporal behaviors of droplet for impinging sprays. The turbulence model of Durbin is used for comparisons with the k-ε model. The turbulence-induced dispersions of droplets are considered to describe the anisotropy of turbulence effectively and spray/wall interactions are simulated using the model of Lee and Ryou. Present study investigates the overall and the internal structures of impinging diesel sprays such as spray shapes, radius and height of wall sprays, Sauter mean diameter (SMD), local droplet velocity, and local gas velocity and compared the results with experimental data by two adopted turbulence models. When the anisotropy effect of turbulence is included, better predictions for both gas and droplet tangential velocities are obtained, compared to the k-ε model. It is concluded that anisotropic effect of turbulence should be considered for simulating impinging diesel sprays.

Analysis of New DI Diesel Combustion Chamber System using New Spray Wall Impaction Model (새로운 충돌모델을 이용한 신형식 디젤연소실 분석)

  • Chang W. S.;Kim D. J.;Park K.
    • Journal of computational fluids engineering
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    • v.2 no.1
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    • pp.54-65
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    • 1997
  • Wall wetting in diesel engines has been considered as a bad phenomenon because of fuel deposition which makes fuel/air mixing and evaporation worse. In order to avoid the problem, many research works have been carried out. One of the studies is on new combustion chamber systems which are using spray impacting on a wall. In this study a new type of chamber system is analysed using wall impaction model introduced and assessed in the coupled paper. The gas phase is modelled in terms of the Eulerian continuum conservation equations of mass, momentum, energy and fuel vapour fraction, The liquid phase is modelled following the discrete droplet model approach in Lagrangian form. With various conditions the spray distribution, vapor contour and gas flows are analyzed, and then design factors of those combustion systems are recommended.

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Experimental Study of Collision Angle Effects on Heat Transfer During Droplet-wall Collision in Film Boiling Regime (막비등 영역에서 액적-벽면 충돌 시 충돌각도가 열전달에 미치는 영향에 관한 실험적 연구)

  • Park, Junseok;Kim, Hyungdae
    • Journal of ILASS-Korea
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    • v.22 no.3
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    • pp.129-136
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    • 2017
  • Effects of collision angle on heat transfer characteristics of a liquid droplet impinging on a heated wall above the Leidenfrost point temperature were experimentally investigated. The heated wall and droplet temperatures were $506^{\circ}C$ and $100^{\circ}C$, respectively, and the impact angle varied from $20^{\circ}$ to $90^{\circ}$ while the normal collision velocity was constant at 0.27 m/s. The droplet collision behaviors and the surface temperature distribution were measured using synchronized high-speed video and infrared cameras. The major physical parameters influencing upon droplet-wall collision heat transfer, such as residence time, wall heat flux, effective heat transfer area, heat transfer amount, were analyzed. It was found at the constant normal collision velocity that the residence time, wall heat flux and effective heat transfer area were hardly not changed, resulting in the almost constant heat transfer amount.

Application of Impinging Jet Injectors to Boiler Spray System : Possibility and Effects (보일러용 연료분사 시스템의 충돌분무 시스템화의 가능성 진단 및 파급효과 분석)

  • Park, Jong-Hoon;Jung, Ki-Hoon;Yoon, Young-Bin;Hwang, Sang-Seun
    • Proceedings of the KIEE Conference
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    • 1999.11b
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    • pp.460-465
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    • 1999
  • 액체 로켓용 충돌분사형 인젝터는 구조가 매우 간단하면서 고유량의 연료를 분사시킬 수 있기 때문에 여러 엔진에 응용된 바 있다. 본 연구에서는 이러한 인젝터의 특성을 산업용 보일러에 적용하기 위한 기초 실험 및 수치 계산을 수행하였다. 충돌분사 노즐로부터 형성되는 분무의 분포 특성을 실험적으로 측정하였고 이를 실제 조건에 모사하기 위해 수치 계산을 하여, 두 결과를 비교하여보았다. 이로부터 보일러의 효율과 공해물질 저감에 영향을 가져오는 액적의 미립화 특성을 향상시킬수 있는 연료 분사 조건을 제시하였다.

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