• Title/Summary/Keyword: 충돌분무

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Analysis of Spray Combustion for the Performance Prediction of Liquid Rocket Combustor (3차원 분무연소장 해석에 의한 액체추진기관 연소실 성능예측에 대한 연구)

  • 황용석;윤웅섭
    • Journal of the Korean Society of Propulsion Engineers
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    • v.3 no.3
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    • pp.31-39
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    • 1999
  • In this paper, numerical experiment is attempted to analyze and compare the combustion efficiency of the burning sprays due to OFO, FOF triplet / FOOF split doublet injectors. Preconditioned Wavier-Stokes equation system with low Reynolds number $\kappa$-$\varepsilon$ model for turbulence closure, is LU-SGS time-integrated. Spray processes are modeled by DSF analysis with experimentally determined injection characteristics. n-heptane/air global reaction model approximates the combustion for simplicity, and the influence of turbulence on the chemical reaction is included using eddy dissipation model. The results showed the FOF triplet injector of highest combustion efficiency, whereas the OFO type of poet performance. It was also observed that the droplet mean diameter and the average gas temperature due to the mixing efficiency, are the representative parameters for the performance design of combustion.

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Experimental Investigation of Impinged Spray Characteristics of Oxygenated fuels Using BOS Method (BOS법을 이용한 함산소 연료들의 충돌분무특성에 관한 실험적 연구)

  • Bang, Seung Hwan
    • Journal of ILASS-Korea
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    • v.25 no.3
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    • pp.111-118
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    • 2020
  • This paper describes the effect of DME, biodiesel blended fuels on the macroscopic spray characteristics in a high pressure diesel injection system using Background Oriented Schlieren (BOS) method. The BOS method for visualization of impingement evaporation sprays to analyze macroscopic spray properties and evolutionary processes. In this work, the blending ratio of DME in the blended fuel are 0, 50, 100% by weight ratio. In order to investigate the macroscopic impinged spray characteristics under the various injection parameters and blending ratio. In this work, a mini-sac type single-hole nozzle injector with nozzle hole was length 0.7 mm and diameter of 0.3 mm was used. According to the result, the spray area of the collision wall increased as the DME mixing ratio increased, and the evolutionary pattern showed a stepwise increase due to the collision effect of the wall. Also, results of impinged spray area were increased according to increasing injection pressure.

An experimental study on the impingement spray of a common-rail diesel injector (2) -atomization characteristics- (커먼레일식 디젤 인젝터의 충돌 분무에 대한 실험적 연구(2) -미립화 특성-)

  • Lee, C.S.;Park, S.W.;Seo, S.H.
    • Journal of ILASS-Korea
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    • v.8 no.3
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    • pp.19-26
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    • 2003
  • In this study, experimental study on atomization characteristics of the fuel spray impinging on the wall was at different wall distances and angles of wall inclination. The fuel injection system was composed based on the common rail system. and the injection signal was synchronized by the delay generator. The atomization characteristics of the injected spray were analyzed in terms of the SMD and velocities which were measured by using the phase Doppler particle analyzer system. It is revealed that the free spray is atomized actively above 50mm form the injector tip. In the cases of the impinged spray, the 5MD and velocity of the impinged spray are smaller than those of the free spray. The impinged spray has the maximum near the 35mm of the radial distance from the injector axis, and the atomization performance is enhanced with the decrease of the wall distance.

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Spray Characteristics of Nonimpinging-type Injector According to the Injection Pressure Variation and Angular Direction of Orifices (분사압력 및 분사각에 따른 비충돌형 인젝터의 분무특성)

  • Jung, Hun;Kim, Jong-Hyun;Kim, Jeong-Soo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.16 no.3
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    • pp.1-8
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    • 2012
  • A water-flow test was carried out for the nonimpinging-type injector to be equipped on 70 N-class liquid-rocket engine under development. Breakup patterns of injector-spray transit from a smooth jet to wavy one as the injection angle increases, whereas spray-breakup lengths are inversely proportional to the injection pressure. It is confirmed that there exist ruffles on the surface of liquid column, which could be caught through the instantaneous spray images captured by high-speed camera. A phenomenon of spray shedding amplified at the specific pressure level of 0.93 MPa was an unexpected behavior of the injected stream and it is to be investigated further.

Spray Characteristics on Impingement Angle Variation and Mixture ratio of Impinging Injectors (충돌각과 혼합비 변화에 따른 충돌형 분사기의 분무특성에 관한 연구)

  • Gang, Sin Jae;Song, Beom Geun;Song, Gi Jeong;Lee, Jeong Gyu
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.31 no.5
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    • pp.72-79
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    • 2003
  • Spray characteristics were investigated by impinging F-O-O-F type injector with varying the impingement angle through 15, 20 and 30 degree and the mixture ratio(O/F ratio) from 1.5 to 3.0. Experimental results show that the correlation between dispersion and impingement angle is not influenced of the mixture ratio variation, but which has influence on number density, and there is a linear correlation between dispersion and impingement angle. Velocity distribution, standard deviation and SMD of droplets are decreased as the impingement angle increases. Also, it was confirmed that the distribution of droplet size are in accordance with Rosin-Rammler and Upper-limit distribution.

DEVELOPMENT OF A GENERAL PURPOSE THERMO/FLUID FLOW ANALYSIS PROGRAM NUFLEX WITH WALL IMPINGEMENT AND HEAT TRANSFER ANALYSIS MODEL OF LIQUID FILM (충돌분무와 액막의 열전달 해석모델을 고려한 범용 열/유체 프로그램 NUFLEX의 개발)

  • Kim, H.J.;Ro, K.C.;Ryou, H.S.;Hur, N.
    • Journal of computational fluids engineering
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    • v.13 no.2
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    • pp.68-72
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    • 2008
  • NUFLEX is a general purpose thermo/fluid flow analysis program which has various physical models including spray. In NUFLEX, spray models are composed of breakup and collision models of droplet. However, in case of diesel engine, interaction between wall-film and impingement model considering heat transfer is not coded in NUFLEX. In this study, Lee & Ryou impingement & wall-film model considering heat transfer is applied to NUFLEX. For the verification of this NUFLEX program, numerical results are compared with experimental data. Differences of film thickness and radius between numerical results and experimental data are within 10% error range. The results show that NUFLEX can be used for comprehensive analysis of spray phenomena.

Mass Distribution and Spray Characteristics to Liquid-Gas Line Selection of Unlike Triplet Impinging Injector (비동질 3중 충돌형 인젝터의 기체-액체 라인 선택에 따른 분무특성)

  • Lee, I.C.;Lee, C.J.;Koo, J.Y.
    • Journal of ILASS-Korea
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    • v.11 no.4
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    • pp.205-211
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    • 2006
  • Impinging angle, impinging distance, length eve. diameter and injection pressure of a triplet injector were tested to evaluate the spray characteristics injected by liquid/gas combinations. Two different kinds of unlike triplet sprays were produced by changing the gas and liquid feed lines. One was the G-L-G(Gas-Liquid-Gas) type, and the other was L-G-L(Liquid-Gas-Liquid) type. Spray angles were wider with the G-L-G type than with L-G-L type. Mass distributions in spray were obtained with a, mechanical patternator. Mass distributions were not circular but elliptical distributions. When the range of mechanical patternator to injector decreased, mass distributions were more concentrated in the center region.

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Development of a general purpose thermo/fluid flow analysis program NUFLEX with heat transfer analy sis model of impinging liquid film (충돌분무 액막의 열전달 해석모델을 고려한 범용 열/유체 프로그램 NUFLEX의 개발)

  • Kim, Hyun-Jeong;Ro, Kyoung-Chul;Ryou, Hong-Sun;Hur, Nahm-Keon
    • 한국전산유체공학회:학술대회논문집
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    • 2008.03b
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    • pp.71-74
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    • 2008
  • NUFLEX is a general purpose thermo/fluid flow analysis program which has various physical models including spray. In NUFLEX, spray models are composed of breakup and collision models of droplet. However, in case of diesel engine, interaction between wall-film and impingement model considering heat transfer is not coded in NUFLEX. In this study, Lee & Ryou impingement & wall-film model considering heat transfer is applied to NUFLEX. For the verification of this NUFLEX program, numerical results are compared with experimental data. Differences of film thickness and radius between numerical results and experimental data are within 10% error range. The results show that NUFLEX can be used for comprehensive analysis of spray phenomena.

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The Effect of Ambient Gas Density on the Development of Impinging Diesel Spray (분무실 밀도 변화가 충돌 디젤분무 특성에 미치는 영향)

  • Kim, J.H.;Lee, B.S.;Koo, J.Y.
    • Journal of ILASS-Korea
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    • v.4 no.2
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    • pp.40-46
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    • 1999
  • Experimental investigation of unsteady impinging diesel spray on the flat plate have been carried out using high speed camera and Malvern system. The density ratios of ambient gas to diesel fuel were varied using $N_2$ and Ar gas in the case of 14.9, 21.2, 28.4, 35.1, 40.4, and 50.1. With the increase of gas density ratio, the radial penetration is decreased due to the resistance of the ambient gas. With the increase of the gas density ratio and the distance between nozzle tip and flat plate, the height of spray is increased due to the entrance and circulation. With the increase of gas density ratio, SMD is decreased on the nearby position at the center of flat plate, but SMD is increased on the far position. As the distance between nozzle tip and flat plate is increased, SMD is always decreased.

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An Experimental Study on Characteristics of Twin Spray Ejected from Two Pre Filming Airblast Atomizer (두 개의 공기충돌형 연료분사장치로부터 분사되는 이중분무특성에 관한 실험적 연구)

  • Park, Seung-Gyu;Han, Jae-Seob;Kim, Yoo;Park, Jung-Bae
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 1998.10a
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    • pp.6-6
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    • 1998
  • 항공기용 가스터빈 및 일반적인 산업용 분무시스템에서는 많은 양의 분사액체를 미립화 시키고 시스템의 연속적인 운전과 유지를 편리하게 하기 위하여 여러 개의 분사노즐을 열로 설치하여 동시에 분사하도록 하고 있다. 이렇게 동시에 분사할 경우, 노즐간에 거리가 충분히 크지 않으면 개별적으로 분사된 분무들이 서로 합해져서 하나의 연합된 분무군이 형성된다. 이렇게 Two element에 의해서 형성된 spray는 공급압력이 증가함에 따라 관성력이 증가하게 되어 중심부분에서 액막 혹은 액적상태로서 충돌이 발생하여 복잡한 분무특성을 가질 것이다. 따라서, 연합된 분무군의 특성을 이해하는 것은 응용의 측면에서 매우 중요하다고 할 수 있다.

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