• Title/Summary/Keyword: 분무 특성

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Evolutionary Feature of Spray Droplets Exiting from a Direct-Injection Type Thruster Nozzle-Orifice (직접분사방식 추력기 노즐오리피스로부터 발생하는 분무입자의 발달특성)

  • Kim, Jin-Seok;Jung, Hun;Kim, Jeong-Soo;Park, Jeong;Kim, Sung-Cho
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2009.05a
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    • pp.149-152
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    • 2009
  • Spray characteristic parameters such as droplet mean velocity, diameter, and volume flux are measured at various locations of spray in order to investigate the evolutionary feature of droplets exiting from a direct-injection type thruster nozzle-orifice. The experimental results indicate that the large droplets with high velocity at the center of upstream are broken-up into smaller droplets with low velocity due to their continuous momentum loss to surrounding air along with spray evolution toward downstream. Also it is found that the high volume flux expands its distribution in radial direction as a results of spray spreading and dispersion.

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Two-Dimensional Distribution of Spray Droplets Emanating from an Injector of Liquid-Propellant Thruster (액체추진제 추력기 인젝터 분무액적의 2차원 공간분포)

  • Jung, Hun;Kim, Jin-Seok;Kim, Jeong-Soo;Kim, Sung-Cho;Park, Jeong;Jang, Ki-Won;Su, Hyuk
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.11a
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    • pp.135-138
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    • 2007
  • Two-dimensional distribution characteristics on the spray droplets emanating from an injector employed in a liquid-propellant thruster are investigated through dual-mode phase Doppler anemometry (DPDA). Spray-breakup characteristic parameters such as spray droplet velocity, turbulent intensity, Sauter mean diameter (SMD), number density, and volumetric flux are quantified to scrutinize the macroscopic behavior of injector-spray breakup. The present study will be able to contribute to the comprehension for performance features of the thruster in current use and to the design engineering of a brand-new thruster as well.

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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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Method and characteristics of liquid atomization (액체 미립화의 방법과 특징)

  • 이충원
    • Journal of the korean Society of Automotive Engineers
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    • v.5 no.4
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    • pp.10-16
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    • 1983
  • 액체의 미립화는 기계산업분야 뿐만 아니라, 농약살포, 화학 공학의 분무건조, 반응의 촉진, 분 체제조, 식품공업 등 폭넓게 이용되며 또한 각분야에서 그 필요성이 강조되고 있다. 특히 기계 산업분야에서는 액체연료의 분무연소(boiler, gas turbine, 자동차용engine등) 원자로 노심의 spray cooling, spray drying, spray painting 등 그 이용도는 날로 증가되는 추세에 있다. 액체를 미 립화하는 이유는 각각의 분야나 사용하는 목적에 따라 다르지만, 대별하면 다음과 같다. (1) 액체의 단위 체적당 표면적을 증대시키기 위하여 (2) 직경이 작은 입자의 필요성 (3) 균일한 입경의 액적군을 얻기 위하여 등을 들 수 있다. 액체의 미립화에 대한 요구는 산업의 발당, 대기오염, 생energy 등의 문제가 중요시됨에 따라 다양화되고 있다. 따라서 응용면에서는 atomizer의 성능개선과 설계법, 새로운 미립화방법, 상업에의 분무이용기술, 분무계측법 등의 개발이 필요하게 된다. 액체미립화에서 취급하는 사항은 그 내용에 따라 다음과 같이 분류된다. (1) 액체의 미립화기구 : 기액계면의 불안정성과 분열기구에 관한 것으로, 액체형상으로써 액주, 액막 및 액적으로 나눌 수 있다. (2) 액체의 미립화 방법과 특성 : energy의 종유와 부가방식에 따랄 나누어진다. (3) 합체, 분산, 증발 등 분무의 운동이나 열적거동 (4) 분무입경이나 운동의 계측법과 특성도시 (5) 액체미립화의 각종응용 본보에서는 상기의 각 항목중, 특히 액체의 미립화방법과 분무특성에 대해서만 말하기로 한다.

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Effects of Fuel-Injection Pressure on the Spray Breakup Characteristics in Small LRE Injector (소형 액체로켓엔진 인젝터의 분무 분열특성에 대한 연료분사압력의 영향)

  • Jung, Hun;Kim, Sung-Cho;Park, Jeong;Kim, Jeong-Soo
    • Journal of the Korean Society of Propulsion Engineers
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    • v.11 no.3
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    • pp.50-57
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    • 2007
  • Spray characteristics of an injector in a small liquid rocket engine (LRE) is characterized by Particle Image Velocimetry (PIV) and Dual-mode Phase Doppler Anemometry (DPDA). Instantaneous plane images captured by PIV are examined for the qualitative prediction of spray breakup with the setup of evaluation technique for effect of spray angles on injector performance. DPDA is also applied in order to quantify the average velocity, turbulent intensity, SMD, and number density of spray droplets along the spray stream distance leading to precise observation of spray atomization behavior. An objective of the study is the derivation of design parameters of new injectors and the establishment of performance criteria through the clear understanding of spray characteristics.

미세물분무 소화설비의 현장적용을 위한 실험적 평가

  • 김성원;이경덕;원정일;신창섭
    • Proceedings of the Korean Institute of Industrial Safety Conference
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    • 2002.05a
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    • pp.227-230
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    • 2002
  • 환경문제를 야기하는 할론 소화설비의 사용이 금지되면서 대체소화설비로 관심을 끌며 연구되기 시작한 미세물분무 소화설비이다. 미세물분무는 고압에서 물을 방사하여 $Dv_{0.99}$가 1,000$\mu$m 미만의 물입자를 만들며 작은 물입자로 인해 표면적의 증가와 증발특성이 우수하고, 산소농도를 감소시키는 질식작용과 화염의 냉각작용에 의해 소화작용을 상승시킨다. 이러한 미세물분무의 소화작용에 대한 소규모 화재실험을 기반으로 유류화재의 진압$\cdot$소화특성에 대한 실용화를 위해 실제크기 화재실험을 하였다.(중략)

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Spray Characteristics of the Pressure Swirl Injector for the APU Gas Turbine Engine (APU 가스터빈엔진 압력식 스월인젝터의 분무특성)

  • Choi, Chea-Hong;Choi, Seong-Man;Lim, Byeong-Jun
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.11a
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    • pp.359-364
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    • 2007
  • Spray characteristics of the APU gas turbine engine were investigated. In order to understand blow out phenomena of the APU engine, we performed fuel spray test. In the test, four operating conditions such as sea level idle, sea level max power, 20,000 feet idle, 20,000 feet max power were used as spray experimental conditions. PDPA(phase Doppler Particle Analyzer) was used for measuring the particle diameter and velocity. Also spray visualization was performed by using ND-YAG sheet laser beam. From the test result, in the case of 20,000 feet idle condition, SMD is about 100 ${\mu}m$ and maximum particle velocity is about 10 m/s. For the flame stability, spray quality should be improved at 20,000 feet idle condition.

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Effect of Gas-liquid Ratio on Characterization of Two-Phase Spray Injected into a Cross-flow (횡단유동에 분사된 이유체 분무의 기체 액체비가 분무특성에 미치는 영향)

  • Cho, Woo-Jin;Lee, In-Chul;Lee, Bong-Su;Koo, Ja-Ye
    • Journal of the Korean Society of Propulsion Engineers
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    • v.12 no.1
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    • pp.16-22
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    • 2008
  • The effect of two-phase spray injected into subsonic cross-flow was studied experimentally. External-mixing of two-phase spray from orifice nozzle with L/d of 3 was tested with various air-liquid ratio that ranges from 0 to 59.4%. Trajectory of spray and breakup phenomena were investigated by shadowgraph photography. Detailed spray structure was characterized in terms of SMD, droplet velocity, and volume flux using PDPA. Experimental results indicate that penetration length was increased and collision point of liquid jets approached to nozzle exit and distributions of mist-like spray were obtained by increasing air-liquid ratio.

Spray Characteristics of a Liquid-Liquid Swirl Coaxial Injector Part II : Effect of Recess Configuration (액체-액체 스월 동축형 인젝터의 분무특성 Part II : 리세스 형상에 따른 영향)

  • Kim, Dong-Jun;Kim, Sung-Hyuk;Han, Poong-Gyoo;Yoon, Young-Bin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.10 no.3
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    • pp.9-17
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    • 2006
  • The influences of recess length of a liquid/liquid swirl coaxial injector on spray characteristics were investigated. It was revealed that the internal impinging phenomenon played an important role in the spray characteristics, such as spray angle and breakup length. Also, as the recess length increased, the mean drop size increased due to the increase of effective film thickness and mixing efficiency increased, but in the case of very deep recess length, the mixing efficiency decreased.

A study on the Image processing method for the Measurements of Spray characteristics (분무특성 파악을 위한 이미지 프로세싱 기법 연구)

  • Jeon, Jae-Hyoung;Kim, Tae-Young;Hong, Moon-Geun;Lee, Soo-Yong
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2010.05a
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    • pp.85-88
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    • 2010
  • It is essential to understand the spray characteristics of injectors for the development of liquid rocket engine systems. In this study, the image processing methods for the measurement of the spray characteristics such as spray angle, breakup length and drop size of Gas-Centered Swirl Coaxial(GCSC) injectors have been investigated. The charge-coupled device (CCD) camera with a stroboscope was used to capture the spray images. It is to be hoped that this methods could contribute to acquisition of reliable and worthwhile data for the design of injectors. Moreover, this image processing method will be verified by comparison with other experimental results.

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