• Title, Summary, Keyword: spray parameter

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Optimal Parameter Design for Al/SiC Composites using Design of Experiments (실험계획법에 의한 Al/SiC 복합재료의 최적공정 설계)

  • Lee, K.J.;Kim, K.T.;Kim, Y.S.
    • Journal of Power System Engineering
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    • v.15 no.5
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    • pp.72-76
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    • 2011
  • In this work, the parameter optimization for thermal-sprayed Al/SiC composites have been designed by $L_9(3^4)$ orthogonal array and analysis of variance(ANOVA). Al/SiC composites were fabricated by flame spray process on steel substrate. The hardness of composites were measured using micro-vickers hardness tester, and these results were analyzed by ANOVA. The ANOVA results showed that the oxygen gas flow, powder feed rate and spray distance affect on the hardness of the Al/SiC composites. From the ANOVA results, the optimal combination of the flame spray parameters could be extracted. It was considered that experimental design using orthogonal array and ANOVA was efficient to determine optimal parameter of thermal-sprayed Al/SiC composites.

Numerical Study on the Effects of Design Parameters on the Spray Characteristics of Fire Suppression Nozzles (소화노즐의 분무특성에 대한 설계 변수 영향의 수치해석적 연구)

  • Lee, C.H.;Choi, B.I.;Han, Y.S.;Kim, C.;Chung, H.T.
    • Journal of ILASS-Korea
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    • v.11 no.4
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    • pp.199-204
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    • 2006
  • Numerical investigation has been performed to simulate the spray characteristics in mist-spray fire suppression nozzles in sense of design parameters. Two key shape factors in nozzle orifices. i.e. diameter and length are chosen as simulation parameters. Commercial softwares, FLUENT and FDS with the proper modelings were applied as numerical tools. Main performances of nozzles, i.e., K-factors, spray angles, droplet size, jet velocities and fire suppression time are analyzed for each parameter to find optimal design conditions.

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The Study of the Interaction between Dual Spray by Two Swirl Injectors (이중 선회 분무간의 상호작용에 관한 연구)

  • Park, B.S.;Lee, D.J.;Kim, H.Y.
    • 한국연소학회:학술대회논문집
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    • pp.141-148
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    • 2002
  • Experimental investigation of the interaction between dual spray formed by swirl type injector was conducted. Experimental parameter was fuel temperature, varied in the range from $-20^{\circ}C$ to $120^{\circ}C$. Measuring parameter were vertical distance from injector tip to patternator and gap between injectors. Volumetric distiribution and SMD were measured for the various combination of parameters. The results of present study show that the arithmetic sum of each of spray is not equal to dual spray, but it is equal above specific fuel temperature. As the increases of fuel temperature, SMD decreases and becomes more uniform. As the increases of gap between injectors, fuel volume and SMD at collision area increases, but penetrated fuel decreases.

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Calculation of Fuel Spray Impingement and Fuel Film Formation in an HSDI Diesel Engine

  • Kyoungdoug Min;Kim, Manshik
    • Journal of Mechanical Science and Technology
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    • v.16 no.3
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    • pp.376-385
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    • 2002
  • Spray impingement and fuel film formation models with cavitation have been developed and incorporated into the computational fluid dynamics code, STAR-CD. The spray/wall interaction process was modeled by considering the effects of surface temperature conditions and fuel film formation. The behavior of fuel droplets after impingement was divided into rebound, spread and splash using the Weber number and parameter K(equation omitted). The spray impingement model accounts for mass conservation, energy conservation, and heat transfer to the impinging droplets. The fuel film formation model was developed by integrating the continuity, momentum, and energy equations along the direction of fuel film thickness. Zero dimensional cavitation model was adopted in order to consider the cavitation phenomena and to give reasonable initial conditions for spray injection. Numerical simulations of spray tip penetration, spray impingement patterns, and the mass of film-state fuel matched well with the experimental data. The spray impingement and fuel film formation models have been applied to study spray/wall impingement in high-speed direct injection diesel engines.

Analysis on the Structure of Evaporative Diesel Spray by Using PIV Technique (화상상관법을 이용한 증발 디젤분무의 구조해석)

  • Yeom, Jeong-Kuk;Chung, Sung-Sik;Ha, Jong-Yul
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.6
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    • pp.74-79
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    • 2004
  • The effects of change in injection pressure on spray structure have been investigated in high temperature and pressure field. To analyze the structure of evaporative diesel spray is important in speculation of mixture formation process. Also emissions of diesel engines can be controlled by the analyzed results. Therefore, this study examines the evaporating spray structure by using a constant volume vessel. The injection pressure is selected as the experimental parameter, is changed from 72 MPa to 112 MPa with a high pressure injection system(ECD-U2). The PIV(Particle Image Velocimetry) technique was used to capture flow variation of the evaporative diesel spray. A study on the mixture formation process of diesel spray was executed by the results of flow analysis in this study. Consequentially the large-scale vortex flow could be found in downstream spray and the formed vortex governs the mixture formation process in diesel spray.

Comparision of Spray Angles of Pintle-Type Gasoline Injector with Different Measuring Methods (측정방법에 따른 핀틀형 가솔린 인젝터의 분무각 비교)

  • Kim, K.J.;Rhim, J.H.;No, S.Y.;Moon, B.S.;Kim, J.Y.;Kang, K.G.
    • Journal of ILASS-Korea
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    • v.4 no.4
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    • pp.9-16
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    • 1999
  • Spray angle, a parameter which is most commonly used to evaluate. spray distribution, is important because it affects the axial and radial distribution of the fuel. Spray angles were measured and compared for the pintle-type gasoline fuel injector with n-heptane as a test fuel with the three different measuring techniques, i.e. digital image processing, shadowgraphy and spray patternator, respectively. Fuel was injected with the injection pressures of 0.2-0.35MPa into the room temperature and atmospheric pressure environment. In digital image processing method, the transmittance level greatly influences the spray angle with the axial distance from the injector. From the experimental results by the shadowgraphy technique, it is obvious that the spray angle vary during the injection period. The results of spray angle from the spray patternator show that there exist the different spray angles in the different areas. The spray angles increase with the increase in the injection pressure for the three measurement techniques considered in this study. The spray angle is widely different, especially in the near region from the injector, according to the measurement techniques used in this experimental work.

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Study on the Spray Behavior from Swirl and Fan Spray Type Gasoline Injectors Impinging on the Constant Temperature Flat Plate (스월형 및 팬스프레이형 고압직분식 가솔린 분사기의 상온 평판에서의 분무 충돌 특성에 관한 연구)

  • Kim, Chong-Min;Kang, Shin-Jae;Kim, Man-Young
    • Transactions of the Korean Society of Automotive Engineers
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    • v.14 no.2
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    • pp.100-106
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    • 2006
  • The behavior of spray impinging on the inclined constant temperature flat plate was experimentally investigated. To clarify the wall effect of a high pressure DISI injector, a relative angle of the inclined wall to a spray axis was varied. Spray penetration along the wall was observed optically and it was compared with that of a Fan spray type and Swirl type spray. To evaluate various spray motion quantitatively, a spray path penetration which describe the development of a spray tip along the wall was newly introduced. To observe the structure of an impinging spray, it was visualized by a controlled stroboscope light and its visualized image was captured on an CCD camera. Using the digital image of impinging spray $H_x$ and $R_x$ was extracted to clarify the structure of impinging spray. The main parameter of the relative position of the wall was the inclined angle which was defined as the angle was varied from $0^{\circ}$ (vertical impingement) to $60^{\circ}$ at the same condition.

Simulation of Spray Impingement and Fuel Film Formation in a Direct Injection Diesel Engine (직접분사식 디젤엔진에서의 분무충돌과 연료액막형성 해석)

  • Kim, Man-Shik;Min, Kyoung-Doug;Kang, Bo-Seon
    • Proceedings of the KSME Conference
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    • pp.919-924
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    • 2000
  • Spray impingement model and fuel film formation model were developed and incorporated into the computational fluid dynamics code, STAR-CD. The spray/wall interaction process were modelled by considering the change of behaviour with surface temperature condition and fuel film formation. We divided behaviour of fuel droplets after impingement into stick, rebound and splash using Weber number and parameter K. Spray impingement model accounts for mass conservation, energy conservation and heat transfer to the impinging droplets. A fuel film formation model was developed by Integrating the continuity, the Navier-Stokes and the energy equations along the direction of fuel film thickness. The validation of the model was conducted using diesel spray experimental data and gasoline spray impingement experiment. In all cases, the prediction compared reasonably well with experimental results. Spray impingement model and fuel film formation model have been applied to a direct injection diesel engine combustion chamber.

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A Numerical Study on the emission Characteristics of DI Diesel Engine by Wall Impingement of Spray (벽면 충돌 분사에 의한 DI디젤엔진 배기가스 특성의 수치해석적 연구)

  • 최성훈;황상순
    • Transactions of the Korean Society of Automotive Engineers
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    • v.6 no.3
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    • pp.97-105
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    • 1998
  • High pressure injection is recently used to reduce the emissions and increase the power of DI diesel engine. This high pressure injection makes the spray strike the cylinder wall. This spray/wall impingement is known to affect the emission and performance of DI diesel engine such that it is very important to know the spray/wall impingement process. In this study, multidimensional computer program KIVA-II was used to clarify the effect of spray wall impingement by different injection spray angle with the spray/wall impingement model consiedering rebound and slide motion and also the improved submodel for liquid breakup, drop distortion model.

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An Experimental Study on the Dynamic Behavior of Spray Droplets in the Wind Tunnel (관내 분무액적의 유동특성에 관한 실험적 연구)

  • Park, Dae-Sick;Choi, Heok-Jun;Park, Sang-Gyun;Kim, Myoung-Hwan;Oh, Cheol;Yun, Seok-Hun
    • Proceedings of the Korean Society of Marine Engineers Conference
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    • pp.95-100
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    • 2002
  • This study was experimentally performed to investigate flow characteristics of spray droplets in the wind tunnel. Behavior of the spray droplets in the pipe was observed and the deposition rate of droplets on the surface of pipe as liquid film was measured. The experiments were carried out for a variety of parameter, such as velocity of feed air, spray angle of nozzle, and diameter of droplet. From the visual observation of the spray droplets in the pipe and the measurement of deposition rate on the pipe, the general understanding of droplets behavior for desuperheater was provided.

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