• Title/Summary/Keyword: Spray angle

Search Result 556, Processing Time 0.028 seconds

Study on Spray Characteristics of Single-Hole GDI Injector according to Nozzle Hole Diameter - (2) Comparison of Spray Uniformity and Atomization Characteristics (노즐 홀 직경에 따른 단공 GDI 인젝터의 분무 특성 연구 - (2) 분무 균일도 및 미립화 특성 비교)

  • Park, Jeonghyun;Ro, Seungcheon;Chang, Mengzhao;Park, Suhan
    • Journal of ILASS-Korea
    • /
    • v.25 no.4
    • /
    • pp.154-161
    • /
    • 2020
  • A single spray plume is the basic unit of the entire spray plume and is an important factor in understanding the spray characteristics. However, since the multi-hole GDI injector has a narrow spray angle, the superposition of the spray plumes occurs severely. Therefore, the spray uniformity and the spray atomization characteristics of a single spray plume were analyzed in this study using a single-hole GDI injector. Five single-hole GDI injectors with different nozzle hole diameters were used in the experiment. The uniformity of the spray was evaluated through the analysis of the spray pattern images. In addition, the atomization characteristics were compared using the diameter distribution of the spray droplets obtained using PDPA. As a result, the larger diameter of the nozzle hole, the less uniformity of the spray, and the injection pressure did not have a significant effect on the spray uniformity. It is judged that the surface roughness of the injector has a greater effect on spray uniformity than the diameter of the nozzle hole. Also, the size of the spray droplets increased sharply when the diameter of the nozzle hole was 230 ㎛.

A Review on Spray Characteristics of Bioethanol and Its Blended Fuels in CI Engines

  • No, Soo-Young
    • Journal of ILASS-Korea
    • /
    • v.19 no.4
    • /
    • pp.155-166
    • /
    • 2014
  • This review will be concentrated on the spray characteristics of bioethanol and its derived fuels such as ethanol-diesel, ethanol-biodiesel in compression ignition (CI) engines. The difficulty in meeting the severe limitations on NOx and PM emissions in CI engines has brought about many methods for the application of ethanol because ethanol diffusion flames in engine produce virtually no soot. The most popular method for the application of ethanol as a fuel in CI engines is the blending of ethanol with diesel. The physical properties of ethanol and its derivatives related to spray characteristics such as viscosity, density and surface tension are discussed. Viscosity and density of e-diesel and e-biodiesel generally are decreased with increase in ethanol content and temperature. More than 22% and 30% of ethanol addition would not satisfied the requirement of viscosity and density in EN 590, respectively. Investigation of neat ethanol sprays in CI engines was conducted by very few researchers. The effect of ambient temperature on liquid phase penetration is a controversial topic due to the opposite result between two studies. More researches are required for the spray characteristics of neat ethanol in CI engines. The ethanol blended fuels in CI engines can be classified into ethanol-diesel blend (e-diesel) and ethanol-biodiesel (e-biodiesel) blend. Even though dodecanol and n-butanol are rarely used, the addition of biodiesel as blend stabilizer is the prevailing method because it has the advantage of increasing the biofuel concentration in diesel fuel. Spray penetration and SMD of e-diesel and e-biodiesel decrease with increase in ethanol concentration, and in ambient pressure. However, spray angle is increased with increase in the ethanol percentage in e-diesel. As the ambient pressure increases, liquid phase penetration was decreased, but spray angle was increased in e-diesel. The increase in ambient temperature showed the slight effect on liquid phase penetration, but spray angle was decreased. A numerical study of micro-explosion concluded that the optimum composition of e-diesel binary mixture for micro-explosion was approximately E50D50, while that of e-biodiesel binary mixture was E30B70 due to the lower volatility of biodiesel. Adding less volatile biodiesel into the ternary mixture of ethanol-biodiesel-diesel can remarkably enhance micro-explosion. Addition of ethanol up to 20% in e-biodiesel showed no effect on spray penetration. However, increase of nozzle orifice diameter results in increase of spray penetration. The more study on liquid phase penetration and SMD in e-diesel and e-biodiesel is required.

A Study on the Velocity Characteristics of the Spray Formed by Two Impinging Jets (충돌 제트로 형성되는 분무의 속도 특성에 대한 연구)

  • Choo, Yeon-Jun;Oh, Dai-Jin;Kang, Bo-Seon
    • Journal of ILASS-Korea
    • /
    • v.6 no.2
    • /
    • pp.1-8
    • /
    • 2001
  • In this study, the velocity characteristics of liquid elements formed by two impinging jets is analysed using double pulse image capturing technique. For the droplets formed by low speed impinging jets, the droplet velocities are higher with smaller azimuthal and impingement angle. The maximum droplet velocities are about 25 % lower than jet velocity. With an increase of azimuthal angle, the shedding angles increases but remains lower than azimuthal angle. The velocities of ligaments formed by high speed impinging jets gradually decreases with an increase of azimuthal angle. The maximum ligament velocities are about 40% lower than jet velocity. Higher impingement angles produce lower ligament velocities. The shedding angles of ligament almost increases with the same value of azimuthal angle, which implies that the moving direction of ligaments is radial from the origin as the impingement point.

  • PDF

Modeling of Wall Impingement Process of Hollow-Cone Fuel Spray according to Wall Geometry (벽면 형상에 따른 중공 원추형 분무의 벽 충돌 과정 모델링)

  • Shim, Young-Sam;Choi, Gyung-Min;Kim, Duck-Jool
    • Proceedings of the KSME Conference
    • /
    • 2007.05b
    • /
    • pp.3467-3472
    • /
    • 2007
  • The effects of the wall geometry on the spray-wall impingement process of a hollow-cone fuel spray emerging from a high-pressure swirl injector of the Gasoline Direct Injection (GDI) engine were investigated by means of a numerical method. The ized Instability Sheet Atomization (LISA) & Aerodynamically Progressed Taylor Analogy Breakup (APTAB) model for spray atomization process and the Gosman model were applied to model the atomization and wall impingement process of the spray. The calculation results of spray characteristics, such as a spray development process and a radial distance after wall impingement, compared with the experimental ones by the Laser Induced Exciplex Fluorescence (LIEF) technique. It was found that the radial distance of the cavity angle of 90$^{circ]$ after wall impingement was the shortest and the ring shaped vortex was generated near the wall after spray-wall impingement process.

  • PDF

A Study on the Non-evaporating Diesel Spray Characteristics as a Function of Ambient Pressure in Constant Volume Combustion Chamber (정적챔버에서 분위기 압력에 따른 비증발 디젤분무특성 연구)

  • Jeon, Chung-Hwan;Jeong, Jeong-Hoon;Kim, Hyun-Kyu;Song, Ju-Hun;Chang, Young-June
    • Journal of Advanced Marine Engineering and Technology
    • /
    • v.34 no.5
    • /
    • pp.645-652
    • /
    • 2010
  • The aim of this investigation was study on the non-evaporation diesel spray characteristics injected through a common-rail diesel injector under various ambient pressure. The diesel spray was investigated with observation of macroscopic characteristics such as spray tip penetration and spray cone angle by the shadowgraph and the image processing method. The numerical study was conducted using a computational fluid dynamics code, AVL-FIRE. The breakup models used were WAVE model and standard $k-{\varepsilon}$ turbulence model was applied. The numerical study used input data which spray cone angle and fuel injection rate was achieved by Zeuch's method. Comparison with experimental result such as spray tip penetration was good agreement. Distribution of droplet diameter were conducted on four planes where the axial distances were 5, 15, 39 and 49mm respectively downstream from the orifice exit.

The Static Pressure Distribution and Flow Characteristics Inside the High-Pressure Swirl Spray (고압 스월분무 내부의 압력분포 및 유동특성에 대한 연구)

  • Moon, Seok-Su;Abo-Serie, Essam;Choi, Jae-Joon;Bae, Choong-Sik
    • Journal of ILASS-Korea
    • /
    • v.11 no.3
    • /
    • pp.168-175
    • /
    • 2006
  • The static pressure distribution and flow characteristics inside the high-pressure swirl spray were investigated by measuring the static pressure inside the spray and applying the computational fluid dynamics (CFD). The static pressure difference between inner and outer part of spray was measured at different axial locations and operating conditions using a piezo-resislive pressure transducer. To obtain the qualitative value of swirl motion at different operating conditions, the spray impact-pressure at the nozzle exit was measured using a piezo-electric pressure transducer, and the flow angle was measured using a microscopic imaging system. The flow characteristics inside the high pressure swirl spray was simulated by the 1-phase 3-dimensional CFD model. The effect of pressure alternations on spray development was discussed with macroscopic spray images and a mathematical liquid film model. The results showed that the static pressure drop is observed inside the swirl spray as a result of the dragged air motion and the centrifugal force of the air. The recirculation vortex inside the spray was also observed inside the swirl spray as a result of the adverse pressure gradient along the axial locations. The results of analytical liquid film model and macroscopic spray images showed that the static pressure structure is one of the main parameters affecting the swirl spray development.

  • PDF

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
    • /
    • v.6 no.3
    • /
    • pp.97-105
    • /
    • 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.

  • PDF

An Study on the Spray Structure of Fuel Port Injectors (포트 분사 연료 인젝터의 분무 구조에 관한 연구)

  • Lee, C.S.;Lee, K.H.;Chon, M.S.;Sohn, K.H.;Park, J.S.
    • Journal of ILASS-Korea
    • /
    • v.3 no.3
    • /
    • pp.42-48
    • /
    • 1998
  • This study describes the spray structure of gasoline port injectors by using phase Doppler particle analyzer(PDPA) and particle motion analysis system(PMAS). The characteristics of fuel spray such as the spray penetration, spray angle and breakup processes were obtained by PMAS and the droplet size and mean velocity were measured by PDPA system. Pintle type and two-hole type injectors were used as gasoline port fuel injectors under various injection pressures. The effect of injection pressure on the droplet mean diameter and axial mean velocity of droplet were investigated under the various injection conditions. In addition the comparison of breakup processes for the two types of injectors was also conducted. It Is shown that pintle type injector has smaller droplet size than that of two-hole type injector.

  • PDF

Spray Characteristics of Charge Injected 2-fluid Nozzle for Non-conducting Liquid (비전도성 액체의 전하주입형 2-유체 노즐에 대한 분무 특성)

  • Park, Min-Gyu;Choi, Young-Joo;Kim, Sang-Soo
    • Journal of ILASS-Korea
    • /
    • v.11 no.3
    • /
    • pp.155-160
    • /
    • 2006
  • Spray characteristics of charge injected 2-fluid nozzle for non-conducting liquid have been studied. Spray current, specific charge and SMD of diesel have been measured. Spray current and specific charge are proportional to applied voltage. Air flow did not effect on spray current and specific charge. SMD decreases as air flow rate increases and decreases as applied voltage increases additionally. Spray angle increases as applied voltage increases. Fine droplets are obtained by charge injected 2-fluid nozzle without charge loss.

  • PDF

Spray Visualization of the Gas Turbine Vaporizer (가스터빈 기화기의 분무 가시화 연구)

  • Jo, Sungpil;Joo, Milee;Choi, Seongman;Rhee, Dongho
    • Journal of ILASS-Korea
    • /
    • v.24 no.3
    • /
    • pp.130-136
    • /
    • 2019
  • Spray visualization of a vaporizer fuel injection system of a micro turbo jet engine was experimentally studied. The fuel heating by combustion was simulated by the high pressure steam generator and combustor inlet air from the centrifugal compressor was simulated by compressed air stored in the high pressure air tank. Spray visualization was performed with single vaporizer, and then six vaporizers which are same number of micro turbojet engine were used. As a results, the spray characteristics of the vaporizer were understood with pressure difference of the combustor inlet air and the fuel supply pressure. Spray angles with three types of vaporizer configuration were measured. In the results, guide vane configuration has a wider spray angle than the straight tube and smooth curve tube with a swirler, so it is expected that the fuel will be effectively distributed inside the combustor flame tube.