• Title/Summary/Keyword: spray width

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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.

Assessment of Dispersion Coefficients and Downward Positions of Water Spray for Small-Scale Release of Chlorine Gas

  • Jang, Seo-Il;Kim, Youngran;Yu, Wooyun;Shin, Dongil;Park, Kyoshik;Kim, Tae-Ok
    • Journal of the Korean Institute of Gas
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    • v.19 no.1
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    • pp.51-56
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    • 2015
  • To assess downward positions of water spray for the small-scale release of chlorine gas, dispersion coefficients for the Gaussian dispersion model were validated at the small-scale release experiment. And the downwind distances of water spray were assessed with the simulated results. As results, the Gaussian plume model using the Briggs' dispersion coefficient well estimated the dispersed characteristics for small-scale release of chlorine gas. The best adequate downwind position of water spray is the position of the maximum concentration of chlorine at the ground level. And the adequate vertical and horizontal dimensions of water spray consider the maximum width and height of cloud.

Effect of Injection Pressure on Atomization Characteristics of Fuel Spray in High-Pressure Gasoline Injector (가솔린 인젝터의 연료 분무 미립화 특성에 미치는 분사 압력의 영향)

  • Lee, Chang-Sik;Choi, Soo-Chon;Kim, Min-Kyu;Kwon, Sang-Il
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.4
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    • pp.555-560
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    • 2000
  • This paper describes the macroscopic behavior and atomization characteristics of the high-pressure gasoline injector in direct-injection gasoline engine. The global spray behavior of fuel injector was visualized by shadowgraph technique. The atomization characteristics of gasoline spray such as mean diameter and mean velocity of droplet were measured by the phase Doppler particle analyzer system. In order to obtain the influence of fuel injection pressure, the macroscopic visualization and experiment of particle measurement on the fuel spray were investigated at 3,5 and 7 MPa of injection pressure under different surrounding pressure in the spray chamber. The results of this work show that the fuel injection pressure of gasoline injector in GDl engine has influence upon the mean droplet diameter, mean velocity of spray droplet, the spray tip penetration, and spray width under the elevated ambient pressure.

Effect of injection pressure on the atomization characteristics of a liquid sheet-type swirl injector for Urea-SCR system (Urea-SCR시스템 액막형 선회분사기의 분사압력변화에 따른 무특성에 관한 연구)

  • Kim, Duckjin;Yang, Donguk;Lee, Jeekeun
    • Journal of Advanced Marine Engineering and Technology
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    • v.37 no.5
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    • pp.510-519
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    • 2013
  • In this study, the spray characteristics of a pressure swirl atomizer classified into a liquid sheet-type swirl nozzle for Urea-SCR system were investigated experimentally with the variation of injection pressure. The length to diameter ratio ($l_o/d$) of the nozzle was 3.1, and the swirler was set inside the nozzle tip to give injecting fluid angular momentum. The injection duration of the nozzle was controlled by PWM (pulse width modulation) modes. The development processes of the spray were imaged by a 2-D PIV system, and the change of spray angle was measured. The atomization characteristics, including axial velocity and SMD, were measured using a 2-D PDA system with the injection pressures at room temperature and ambient pressure conditions. As the experimental results, the injection pressure had a significant impact on the spray structure showing a different shape around the spray leading edge, and the smaller SMD was observed with increasing injection pressures, which was similar to that of the previous work.

Tomographic reconstruction of Asymmetric Spray by Direct Sampling Method (직접샘플링에 의한 비대칭 분무의 토모그래피 재구성)

  • Lee, C.H.;Won, J.C.
    • Journal of ILASS-Korea
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    • v.7 no.4
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    • pp.9-15
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    • 2002
  • Convolution Fourier transformation tomographically reconstructs the spatially resolved spray injection rate from direct measuring cells. Asymmetric sprays generated from a twin-hole air shroud injector are tested with 12 equiangular projections of measurements. For each projection angle, line of sight integrated injection rate was measured at 35 positions with equal spacing measuring cells of 3 mm in width, 100 mm in length, 55 mm in depth and 0.5 mm thickness of separating wall. Interpolated data between the projection angles effectively increase the number of projections, which significantly enhances the signal-to-noise level in the reconstructed data. This modified convolution Fourier transformation scheme predicts well the structure of asymmetric sprays. Comparative study has been made between sprays with and without air shrouding. Tomograhpic reconstruction of injection rate from direct measuring cells obtained can be used to estimate the accuracy of volume fraction of spray from the LDPA tomographic reconstruction.

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Fire Suppression Experiment for Road Tunnel Low Pressure Water Spray Systems (도로터널 저압 물분무설비 화재진압 실험)

  • Choi, Byung-Il;Han, Yong-Shik;Kim, Myung-Bae;So, Soo-Hyun
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 2008.04a
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    • pp.218-221
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    • 2008
  • The real scale fire suppression test inside a road tunnel were carried out for water spray systems. The dimension of the tunnel is 7.5m in height and 11.6m in width. 3 different water spray nozzle systems with low operating pressure less than 3.5 bar were used in the experiment. Two types of fires were tested. One is a $1.4m^2$ heptane pool fire and the other is a 2000CC passenger car fire. From the experiment, the spray densities of tested systems were about $6.0\;l/min/m^2$ which is currunt domestic guideline. Although all the systems cannot extinguish the tested fires, it was found that they can reduce the tunnel temperature and have a capability to control and suppress the tested fire.

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A Study on Surface Characteristics of High Tensile Brass with Molybdenum Flame Spray Treatment (고력황동의 몰리브덴 화염용사에 따른 표면 특성에 관한 연구)

  • Jung, Dong-Hyun;Kim, Hae-Ji
    • Journal of the Korean Society of Manufacturing Process Engineers
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    • v.17 no.6
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    • pp.38-45
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    • 2018
  • Molybdenum flame spray coatings are widely used in industrial fields to enhance the performance of mechanical component parts such as pistons, shafts and clutches. This study investigates the surface characteristics of high tensile brass with molybdenum flame spray treatment using the clutch material for small ship. The surface characteristics after molybdenum flame spray treatment in high tensile brass were quantitatively analyzed for surface composition, coating layer thickness, friction coefficient, abrasion width and phenomenon, micro-hardness, and surface roughness.

Turbulent Mixing Flow Characteristics of Solid-Cone Type Diesel Spray

  • Lee, Jeekuen;Shinjae Kang;Park, Byoungjoon
    • Journal of Mechanical Science and Technology
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    • v.16 no.8
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    • pp.1135-1143
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    • 2002
  • The intermittent spray characteristics of the single-hole diesel nozzle (d$\sub$n/=0.32 mm) used in the fuel injection system of heavy-duty diesel engines were experimentally investigated. The mean velocity and turbulent characteristics of the diesel spray injected intermittently into the still ambient were measured by using a 2-D PDPA (phase Doppler particle analyzer) . The gradient of spray half-width linearly increased with time from the start of injection, and it approximated to 0.04 at the end of the injection. The axial mean velocity of the fuel spray measured along the radial direction was similar to that of the free air jet within R/b= 1.0-1.5 regardless of elapsing time, and its non-dimensional distribution corresponds to the theoretical velocity distributions suggested by Hinze in the downstream of the spray flow fields. The turbulent intensity of the axial velocity components measured along the radial direction represented the 20-30% of the U$\sub$cι/ and tended to decrease in the outer region. The turbulent intensity in the trailing edge was higher than that in the leading edge.

Spray Characteristics of a Modulated Liquid Jet through 2nd Pulsed Control (2차 가진 제어 변조분사 특성 및 액체제트의 분무특성)

  • Kang, Young-Su;Lee, In-Chul;Koo, Ja-Ye
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.11a
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    • pp.672-675
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    • 2010
  • Spray characteristics for the modulation with a pulsed spray in low-frequency region were investigted by performing with additional internal pulsed injection. The 1st perturbative flow was generated by rotating-type pulsed device and the 2nd pulse source generated by the magnetic valve was used to modulate the 1st flow. A pattern of the modulated spray was observed through FFT result and visualization. In case of modulated spray with the 2nd pulse control, the width of up and down motion of the modulated spray is smaller than that of the spray without the 2nd pulse. Also, the depth of penetration of the down stream is higher than that of spray without the 2nd pulse.

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SPRAY AND COMBUSTION CHARACTERISTICS OF HYDROCARBON FUEL INJECTED FROM PRESSURE-SWIRL NOZZLES

  • Laryea Gabriel Nii;No Soo-Young
    • Journal of ILASS-Korea
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    • v.9 no.4
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    • pp.31-37
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    • 2004
  • This paper presents spray and combustion characteristics of hydrocarbon fuel injected from pressure-swirl nozzles. Three commercial nozzles with orifice diameters of 0.256, 0.308 and 0.333mm and injection pressures ranging from 0.7 to 1.3 MPa were selected f9r the experiments. Spray characteristics such as breakup length. spray angle and drop size (SMD) were analyzed using photo image analyses and Malvern Panicle Size Analyzer. The drop size was measured with and without a blower at the same measuring locations. The flame length and width were measured using photo image analyses. The temperature distribution along the axial distance and the gas emission such as CO, $CO_2\;and\;NO_x$ were studied. The breakup length decreased with an increase in injection pressure for each nozzle but increased with an increase in nozzle orifice diameter. The spray angle increased and SMD decreased with an increase in injection pressure. The flame with an increased linearly with an increase in injection pressure and in nozzle orifice diameter. The flame temperature increased with an increase in injection pressure but decreased along the axial distance. The maximum temperatures occurred closer to the burner exit and flame at axial distance of 242mm from the diffuser tip. The experimental results showed that the level of CO decreased while that of $CO_2\;and\;NO_x$ increased with an increase in injection pressure and nozzle orifice diameter.

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