• 제목/요약/키워드: Liquid Atomization

검색결과 949건 처리시간 0.024초

Atomization Improvement of a Liquid Jet with Wall Impingement and its Application to a Jet Engine Atomizer

  • Shiga, Seiichi
    • 한국분무공학회지
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    • 제11권3호
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    • pp.176-189
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    • 2006
  • In the present study, capability of improving the liquid atomization of a high-speed liquid jet by using wall impingement is explored, and its application to a jet engine atomize. is demonstrated. Water is injected from a thin nozzle. The liquid jet impinges on a wall positioned close to the nozzle exit, forming a liquid film. The liquid film velocity and the SMD were measured with PDA and LDSA, respectively. It was shown that the SMD of the droplets was determined by the liquid film velocity and impingement angle, regardless of the injection pressure or impingement wall diameter. When the liquid film velocity was smaller than 300m/s, a smaller SMD was obtained, compared with a simple free jet. This wall impingement technique was applied to a conventional air-blasting nozzle for jet engines. A real-size air-blasting burner was installed in a test rig in which three thin holes were made to accommodate liquid injection toward the intermediate ring, as an impingement wall. The air velocity was varied from 41 to 92m/s, and the liquid injection pressure was varied from 0.5 to 7.5 MPa. Combining wall impinging pressure atomization with gas-blasting produces remarkable improvement in atomization, which is contributed by the droplets produced in the pressure atomization mode. Comparison with the previous formulation for conventional gas-blasting atomization is also made, and the effectiveness of utilizing pressure atomization with wall impingement is shown.

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회전컵 무화기의 미립화 특성에 관한 실험적 연구 (An Experimental Study on the Atomization Characteristics of the Rotary Cup Atomizer)

  • 진승범;조대진;윤석주
    • 한국분무공학회지
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    • 제6권4호
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    • pp.14-21
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    • 2001
  • Rotary atomizer is widely used in practical application ranging from combustion, cooling, spray drying, agriculture, chemical system. Rotary cup atomizer has some advantages such as extreme versatility and liquid atomization successfully varying widely in viscosity. In rotary atomization, the feed liquid is centrifugally accelerated to high velocity and the liquid extends over the rotating surface as a thin film before being discharged into an atmosphere. The degree of rotary atomization depends upon peripheral speed, feed rate, liquid properties and atomizer design. An important asset is that thickness and uniformity of the liquid sheet can readily be controlled by regulating the liquid flow rate and the rotational speed. LDPA(Laser Diffraction Particle Analyser) and image aquisition system are used to measure drop size distribution and spray pattern. The atomization characteristics of the rotary cup atomizer is investigated experimentally by varing the liquid feed rate, rotary cup speed and air velocity for atomization. As a results, the effect of air velocity on the atomization characteristics such as drop size and spray uniformity is considerably greater than variation of those with liquid feed rate.

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2유체 정전분무의 액체 미립화 및 분무 특성 (Liquid Atomization and Spray Characteristics in Electrostatic Spray of Twin Fluids)

  • 김정헌;배충식
    • 대한기계학회논문집B
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    • 제25권11호
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    • pp.1552-1560
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    • 2001
  • This paper presents the experimental results of a study undertaken to develop an electrostatic spray system for a combustion application. The characteristics of the liquid atomization and the droplet dispersion in the electrostatic spray of twin fluids were investigated by the optical measurement techniques. The processes associated with the break-up of charged jets were also observed using the laser sheet visualization. The diameter and velocity of droplets were simultaneously measured using the phase Doppler measurement technique. The electrostatic atomization of the liquid fuel depended primarily on the charging voltage and the flow rate, but the dispersion of droplets depended significantly on the aerodynamic flow. Aerodynamic influences on the liquid atomization decreased with an increase of the charging voltage. Consequently, the liquid atomization and the droplet dispersion could be independently controlled using the electrostatic and aerodynamic mechanisms.

2-유체 분무에서 액체미립화에 대한 초음파의 영향에 관한 연구 (A Study on Ultrasonic Effects for the Atomization in a Twin-Fluid Spray)

  • 주은선;정진도;송민근
    • 한국분무공학회지
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    • 제3권4호
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    • pp.50-57
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    • 1998
  • The utilization of resonance should be considered to get the maximum effect of ultrasonic to atomize liquid. The ultrasonic generator, transducer, horn, and all attached parts are used to produce the resonance, and specially the characteristics of liquids such as liquid load, property, and etc., for the liquid atomization affinity are considered. In this study, the variable device of liquid load was made and distilled water and city water selected as experimental liquids were sprayed by a twin-fluid spray method and their diameters, distributions, and spray quantum of spray droplets were measured by the light scattering system. And all data were observed, compared and considered relatively. In results, a lot of phenomena of liquid atomization affinity by ultrasonic appeared in accordance with liquid loads, namely head h.

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고전압 직류전기장에서 전기수력학적 분무 유동 가시화에 관한 연구 (A Study on the Visualization of Electrohydrodynamic Spray Flow in High DC Voltages)

  • 성기안
    • 한국분무공학회지
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    • 제11권3호
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    • pp.131-139
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    • 2006
  • An experimental study was performed to investigate the liquid breakup and atomization characteristics in electrohydrodynamic atomization according to the changing of experimental parameters such as nozzle size, fluid flow, and electrical intensity. An original electrohydrodynamic atomizer equipment was designed and manufactured for the analysis of spray visualization and the exploration of relationship between applied power and the behavior of liquid atomization. The image processing technique by using the back-illumination method was applied to visualize the distilled liquid breakup process and to examine the variation of the droplet size distribution. The results show that the spray modes of electrohydrodynamic atomization are closelyconnected by the strength of the electric stresses at the surface of the liquid film and the kinetic energy of the liquid jet leaving the needle tip.

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용융금속 미립화에 관한 기초적 연구 (A Fundamental Study on the Gas Atomization of Liquid Metal)

  • 강민성;최종윤;김희동
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2008년도 추계학술대회B
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    • pp.2777-2781
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    • 2008
  • Gas atomization of liquid metal using nozzle technology has more advantages over other methods. Previous study shows that high-velocity gas is important for effective liquid metal atomization. An important first step towards understanding the gas atomization using nozzle is complete evaluation of the flow fields. This will provide a basis for understanding how well high velocity gas is brought to bear on the liquid metal. Present work is a fundamental study of liquid metal atomization for various pressure ratio, different gas and temperature. A two-dimension, axisymmetry compressible Navier-Stokes equations are considered. Two-equation k-epsilon turbulence model is selected.

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초음파에 의한 액체 미립화 특성에 관한 연구 (A study on Characteristics of the Liquid Atomization by Ultrasonic)

  • 주은선;나우정;최우창
    • 한국자동차공학회논문집
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    • 제7권5호
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    • pp.31-39
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    • 1999
  • A good atomization in uniform size brings the elevation of thermal efficiency in spray combustion, the beautiful painting on surfaces, and the economical sprinkling of chemicals. Ultrasonic atomization has been expected as a good uniform atomization mechanism due to its uniform size distribution. Influx, load, and physical properties of liquids are the effecting factors to atomize liquids. In this study, distilled water and city water are selected as reference liquids and gasoline, kerosene, and petroleum as fuel liquids. Characteristics and affinity to get the maximum effect for the ultrasonic atomization are observed by using the two ultrasonic transducers with 28kHz and 2MHz. Results show that the size distributions of liquid spray dorplet by the direct vibration method prevail over those by the aerosol method in uniform droplet size and as a whole, sizes of spray liquid droplets are increased slightly according to increasing influx in the direct vibration method and quantities of spray droplets in the aerosol method decreasing according to increasing liquid load h.

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Development of Plate-type Fine Atomizing Nozzles for SI Engines with Intake-port Fuel Injection

  • Suzuki, Takashi;Tani, Yasuhide
    • 한국분무공학회지
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    • 제12권1호
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    • pp.45-57
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    • 2007
  • This paper presents both experimental and numerical studies regarding nozzles used for the SI engine application, particularly for the intake-port fuel injection type. The atomization mechanism of the multi-hole plate nozzle was investigated experimentally. It was found that the nozzle design added turbulence into the liquid-film jet and the jet disintegrated rapidly. Based on the results, various plate types for the nozzle were developed and tested; six hole nozzle for liquid jet interaction, plate-type nozzle with flat duct channel, and the simpler structured nozzle. The spray characteristics of the prototype nozzles were examined experimentally while the internal flow of the nozzle was investigated computationally. It was shown that turbulent liquid-film was injected and atomization quality was improved by controlling the internal flow condition of the plate-type nozzle.

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유해배기가스 저감을 위한 Hole형 노즐의 미립화 특성실험 (Atomization Characteristics Experiment of Hole Type Nozzle for the Reduction of Harmful Exhausted Gas)

  • 정진도;유병구
    • 한국분무공학회지
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    • 제2권3호
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    • pp.17-24
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    • 1997
  • A simplified experiment was performed to figure out the atomization characteristics of rice-bran oil which it is highly viscous liquid by applying ultrasonic energy. A spray system, an ultrasonic system, and three kinds of hole-type nozzles(hole diameter: 0.31, 0.34, 0.37mm) were manufactured. To investigate the effects of ultrasonic energy on the atomization of a highly viscous liquid, a phase doppler particle analyzer was used for measurement and calculation of spray droplets data. Nozzle opening pressures were chosen of 3 levels, i.e, 16, 20, and 24MPa. As a result, it could be concluded that the ultrasonic energy was effective to improve the spray atomization when it applied to the fuel by means of 3 different nozzles because of the effects of the liquid fuel cavitation and relaxation between molecules caused by ultrasonic energy. The improvement rate of the spray atomization by the ultrasonic method compared with the conventional spray increased about 15% in the case of hole type nozzles. By increasing of the nozzle opening pressure and decreasing of the hole diameter, the atomization of spray droplets was improved.

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다공 스로틀 밸브에서의 액체 연료의 2차 미립화 특성에 관한 연구 (A Study on the Secondary Atomization Characteristics of Liquid Fuel in the Perforated Throttle Valve)

  • 이창식;이기형;조병옥;오군섭
    • 한국분무공학회지
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    • 제1권1호
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    • pp.55-62
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    • 1996
  • In a fuel injection engine, atomization of liquid fuel and mixture formation process has influenced(or affected) directly on the engine performance and pollutant emission. In this study, the characteristics of fuel spray and the behaviors of secondary atomization developed at the downstream of the valves were investigated using an image processing method. Solid and perforated valves are chosen in order to evaluate the valve performance in terns of air flow rate, valve opening angle and valve shape. Experimental results clearly indicate that the spray atomization quality can be improved by increasing the perforated rat io and the blockage rat io in the perforated valve, the characteristics of spray atomization is improved by using the perforated valve with high perforated rat io and blockage ratio.

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