• Title/Summary/Keyword: Spray Column

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Disintegration Process of the Rotating Fuel Injector (회전연료 분사시스템의 분열과정)

  • Jang, Seong-Ho;Lee, Dong-Hun;You, Gyung-Won;Choi, Seong-Man
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.171-174
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    • 2008
  • This paper presents disintegration process of the small rotational fuel injector. In order to understand disintegration precess, we measured droplet diameter, velocity and spray distribution by the PDPA(Phasse Doppler Particle Analyzer) system. Also spray was visualized by using Nd-Yag flash photography. From the test results, the liquid column emerging from the injection orifice is mainly controlled by the rotational speeds. Furthermore, droplet diameter(SMD) and spray distribution were strongly influenced by the diameter of the injection orifice.

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Characteristics of Liquid-Liquid Direct Contact Heat Exchanger for a Solar System (태양열 이용을 위한 직접접촉식 액-액 열교환기 특성)

  • 강인석;김종보;강용혁;곽희열
    • Transactions of the Korean Society of Mechanical Engineers
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    • v.18 no.12
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    • pp.3276-3286
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    • 1994
  • In most direct contact liquid-liquid heat exchangers, oil or hydrocarbon with a density less than water is normally used as dispersed working fluid. The main difficulty that arises with this arrangement lies in the control of the interface at the top of the column. When it is connected with a solar collector which uses water as its working fluid, the main difficulties arise from the fact that the water can be frozen during winter time. In order to solve these problems and to demonstrate the technical feasibility of a direct contact liquid-liquid heat exchanger, liquids heavier than water with low freezing temperature has been utilized as dispersed phase liquids in a small laboratory scale model made of pyrex glass. In the present investigation, dimethyl phthalate(C/sub 6/H/sub 4/)COOCH/sub 3/)/sub 2/) and diethyl phthalate (C/sub 6/H/sub 4/(CO/sub 2/C/sub 2/H/sub 5/)/sub 2/) are utilized as heavy dispersed phase working fluids. The results of the present investigation the technical in the utilization of heavier dispersed working liquid in the spray-column liquid-liquid heat exchanger for a solar system. The overall average temperature difference along the column is found to be almost half of the initial temperature difference between the dispersed and the continuous phase. Despite the fact that the two phthalates tested in the experiment differ significantly in some of their physical properties, the volumetric heat transfer coefficients in terms of dispersed fluid superficial velocities were found to be similar for both phthalates tested.

A Study on a Heat Transfer Characteristics of Direct Contact Heat Exchanger for Steam Condensation According to Various Cooling Water Flow and Internal Pressure(The Purpose of Combination with LNG Evaporator) (증기응축용 직접접촉식 열교환기의 냉각수 유량과 내부압 변화에 따른 열전달 특성연구(LNG 기화기와의 조합목적))

  • Lee, B.C.;Han, S.T.;Kim, C.B.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.3 no.3
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    • pp.153-160
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    • 1991
  • Heat transfer characteristics of a direct contact heat exchanger utilizing sieve trays and spray nozzles for steam condensation for the purpose of combining with a LNG evaporator have been investigated with various cooling water flow rates and different vacuum pressures within the heat exchanger for the purpose of steam condensation. Temperature profiles and the volumetric overall heat transfer coefficients in a direct contact heat exchanger have been obtained for comparisons. The results show that the temperature differences between cooling water and steam along the direct contact heat exchanger height are rapidly decreasing and the volumetric overall heat transfer coefficients of the exchanger improves greatly as the inside vacuum pressure increases. The values of the overall heat transfer coefficients at P=-680mmHg have been increased significantly compared with at atmospheric pressure. At given pressure conditions, it is found that the values of average volumetric overall heat transfer coefficients for the sieve tray are found to be approximately 10% higher than those of the spray nozzle.

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Atomizing Characteristics of Coaxial Porous Injectors (다공성재를 이용한 동축형 분사기의 미립화특성)

  • Kim, Do-Hun;Shin, Jeung-Hwan;Lee, In-Chul;Koo, Ja-Ye
    • Journal of ILASS-Korea
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    • v.17 no.1
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    • pp.35-44
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    • 2012
  • To improve the mixing and atomizing performance at the center region of the conventional coaxial shear injector spray, the concept of a coaxial porous injector was invented. This novel injection concept for liquid rocket engines utilizes the Taylor-Culick flow in the cylindrical porous tube. The 2-dimensional injector, which can be converted in three injection configurations, was fabricated, and several cold flow tests using water-air simulant propellant was performed. The hydraulic characteristics and the effects of a gas flow condition on the spray pattern and the Sauter mean diameter (SMD) was analyzed for each configuration. The atomizing mechanism of coaxial porous injector was different with the coaxial shear injector, and it was explained by the momentum of the gas jet, which is injected normally against the center liquid column, and by the secondary disintegration at the wavy interface of liquid jet, which was generated at the recessed region. The SMD of 2D coaxial porous injector, which has higher gas momentum, was measured and it shows better atomizing performance at the center and outer side of spray than the 2D coaxial shear injector.

Properties of Temperature History and Spatting Resistance of High Performance RC Column with Finishing Material (내화 마감재 종류에 따른 고성능 RC기둥의 폭열방지 및 온도이력 특성)

  • Heo Young-Sun;Kim Ki-Hoon;Lee Jin-Woo;Lee Bo-Hyeung;Lee Jae-Sam;Han Cheon-Goo
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2005.05a
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    • pp.37-40
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    • 2005
  • High Performance Concrete(HPC) has been widely used in high-rise building. The HPC has several benefits including high strength, high fluidity and high durability. However. spatting is susceptible to occur in HPC and HPC also tends to be deteriorated in the side of fire resistance performance at fire. This paper focuses on the analysis of the temperature history and residual compressive strength with finishing material, in order to protect HPC from sudden-high-temperature, which is one of the main reason spatting occurs. Test results show that spalling occurs in all specimens. The most serious spalling took placed in HPC covering fire enduring spray-on material, whose covering thickness is 20mm but temperature history indicates that fire enduring spray effectively protected HPC from fire for more than 2hours. In addition, residual compressive strength ratio of HPC using fire enduring paint was more than $90\%$ of original strength, thus minimizing spatting and indicating significant fire resistance performance.

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The Effect of Cross-flow on Liquid Atomization (횡단유동이 액체 미립화에 미치는 영향)

  • Kim, Jong-Hyun;Cho, Woo-Jin;Lee, In-Chul;Lee, Bong-Soo;Koo, Ja-Ye
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.2
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    • pp.87-92
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    • 2008
  • The breakup processes and spray plume characteristics of liquid jets injected in subsonic air cross-flows were experimentally studied. The behaviors of column, penetration, breakup of plain liquid jet and droplet sizes, velocities have been studied in non-swirling cross-flow of air. Nozzle has a 1.0 mm diameter and Lid ratio=5. Experimental results indicate that the breakup point is delayed by increasing air momentum, the penetration decreases by increasing Weber number and the split angle is increased by increasing air velocity or decreasing injection velocity. SMD increases according as increasing height or decreases in accordance with increasing air velocity. This phenomenon is related to the momentum exchange between column waves and cross-flow stream. Droplet vector velocities were varied from 11.5 to 33 m/s. A higher-velocity region can be identified in down edge region at Z/d=40, 70 and 100. Lower-velocity region were observed on bottom position of the spray plume.

An Experimental Study on the Trajectory Characteristics of Liquid Jet with Canted Injection Angles in Crossflow (수직분사제트에서 다양한 분사각도의 분무궤적 특성에 대한 실험적 연구)

  • Kim, Min-Ki;Song, Jin-Kwan;Hwang, Jeong-Jae;Yoon, Young-Bin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.6
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    • pp.38-47
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    • 2008
  • The liquid column and spray trajectory have been experimentally studied in liquid jets injected into subsonic crossflow. With water as fuel injection velocity, injection angle were varied to provide of jet operation conditions. The Pulsed Shadowgraph Photography and Planar Liquid Laser Induced Fluorescence technique was used to determine the injection characteristics in a subsonic crossflow of air. And the mainly objectives of this research was to get a empirical formula of liquid column and spray region trajectory with forward and reversed injection of air stream. As the result, This research has been shown that each trajectories were spatially dependent on air-stream velocity, fuel injection velocity, various injection angle, and normalized injector exit diameter. Furthermore, the empirical formula of liquid column trajectories has been some different of drag coefficient results between forward and reversed angled injection.

Preparation of High Performance Hybrid Chemical Filter using Hot Melt Adhesive by Web Spray and Their Adsorption Properties (핫멜트 Web spray법을 이용한 고기능성 복합 화학필터의 제조 및 흡착특성)

  • Choi, Yong Jae;Shin, Kyoung Sub;Hwang, Taek Sung
    • Journal of Adhesion and Interface
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    • v.10 no.3
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    • pp.141-147
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    • 2009
  • In this study, the high performance hybrid chemical filter (HPHCF) was prepared by web spray using hot melt adhesive. The material of HPHCF was conditionally made of ion exchange resin and PP non-woven fabric. The optimum temperature and pressure for manufacturing of HPHCF conditions were such as $170^{\circ}C$ and 50 psi, respectively. The characteristics of preparated HPHCF and their adsorption properties of ammonia gas were investigated. The ion exchange capacity (IEC) of HPHCF was increased with increasing the resin contents and their values were higher than pure resin and ion exchange fabrics. The removal efficiency for ammonia gas increased with the increase of packing density of hybrid ion exchange fabrics in the column. It showed 13 min which the adsorption breakthrough time was slower than resin and fibers. The maximum value of adsorption for ammonia gas was 98 percent. And also, the velocity was increased with increasing concentration and flow rate of ammonia gas.

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An Experimental Study of the High-Speed Rotating Fuel Injection System with In-line Injection Orifice (직렬식 분무오리피스를 적용한 회전 연료분사노즐의 분무특성연구)

  • Jang, Seong-Ho;Choi, Seong-Man
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.11a
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    • pp.202-206
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    • 2009
  • We studied the spray characteristics of the high-speed rotating fuel injection system. The diameter of in-line injection orifices are varied from 1mm to 5mm and the number of in-line injection orifices are varied from 3 to 12. Droplet size, velocity and spray distribution were measured by the PDPA(Phase Doppler Particle Analyzer) system and spray was visualized. From the test results, the liquid column generated from the injection orifice is mainly controlled by the rotational speeds. Also diameter of injection orifices and number of injection orifices have influence on the diameters of droplet. Consequently, we find out that the basic mechanism of controlling the droplet size is the liquid film thickness in the injection orifice.

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Droplet Sizes and Velocities from Single-Hole Nozzle in Transversing Subsonic Air-stream (아음속 횡단류에 수직 분사되는 분무의 액적크기 및 속도 분포 특성)

  • Lee, In-Chul;Cho, Woo-Jin;Lee, Bong-Su;Kim, Jong-Hyun;Koo, Ja-Ye
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.04a
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    • pp.106-109
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    • 2007
  • The spray plume characteristics of liquid water jet injected into subsonic cross-flow at 42 m/s were experimentally investigated. Nozzle has a 1.0 m diameter and L/D=5. Droplet sizes, velocities, volume flux were measured at each downstream area of the injector exit using phase Doppler particle anemometry. Measuring probe position is moved with 3-way transversing machine. Experimental results indicate that SMD is varied from 75 to $120{\mu}m$ distribution and it is uncertain layer structure. SMD peaks at the top of the spray plume. This phenomenon is related to the momentum exchange between column waves and cross-flow stream. Droplet vector velocities were varied from 11.5 to 33 m/s. A higher-velocity region can be identified in down edge region at Z/D : 40, 70 and 100. Lower-velocity region were observed on bottom position of the spray plume. Volume flux is a criterion to the droplet concentration. All volume flux distribution has a same structure that continuously decreases from the center region to the edge of the plume. Z/D : 20 is spatially less concentrated than in Z/D : 100.

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