• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1771-1776
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• 2003

The supersonic swirl jet is being extensively used in many diverse fields of industrial processes since those lead to more improved performance, compared with the conventional supersonic no swirl jet. In the present study, an experiment is carried out to investigate the effect of annular swirl jet on the supersonic dual coaxial jet. A convergent-divergent nozzle with a design Mach number of 1.5 is used for the supersonic primary jet, and the sonic nozzles with four tangential inlets are used to make the secondary swirl jet. The primary jet pressure ratio is varied in the range from 3.0 to 7.0 and the outer annular jet pressure ratio is from 1.0 to 4.0. The interactions between the annular swirl and the inner supersonic jet are quantified by the pitot impact and static pressure measurements and visualized by using the Schlieren optical method. The results show that annular swirl jet alters the shock structure and impact pressure distributions compared with no swirl jet.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2010년도 제34회 춘계학술대회논문집
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• pp.14-17
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• 2010

7개 스월 인젝터 연소기의 스월 방향에 따른 유동 특성을 파악하기 위하여 3차원 Large Eddy Simulation(LES)을 수행하였다. 해석에 이용된 연소기 모델은 Georgia 공대 Aerospace Combustion Laboratory의 LRE combustor를 이용하였으며, 경계 조건은 실험에서 얻어진 값을 적용하였다. 7개 인젝터의 스월 방향을 모두 동일한 방향으로 설정하였을 경우, 스월 유동간의 간섭이 증가하게 되고, 연소실 벽면에서 강한 원주방향의 속도 분포가 형성되는 것을 관찰하였다. 또한 연소실 내 압력변동폭은 인젝터의 스월 방향을 상반되게 설정하였을 때보다 현저히 증가한 것을 확인하였다.

• 한국분무공학회지
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• 제20권2호
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• pp.70-75
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• 2015

Swirl flow in the gun type burner has an impact on the stabilization of the flame, improvement of the combustion efficiency. The swirl flow is created by the spinner which is inside the airtube that guide the combustion air. Gun type burner has generally the inner devices composed electronic spark plug, injection nozzle, combustion device adaptor, and spinner. These inner components change the air flow behavior passing through airtube. So, this study conducted the measurement using by hot-wire anemometer and analyzed effect of the swirl number of spinner on the exhaust air of gun type burner. Turbulence characteristics come up in this study was mean velocity, turbulence intensity, kinetic energy, shear stress and flattness factor of the air flow with the change of the distance of axial direction and tangential direction from the exit of the airtube.

• 한국분무공학회지
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• 제2권1호
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• pp.46-51
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• 1997

In this study, spray characteristics of the pressure swirl atomizer have teen investigated. Four atomizers with the different orifice diameter and five tangential ports with the different inlet number were fabricated. For the purpose of the measurement of the mean drop sine, Malvern particle sizer was used. And also discharge coefficient was measured and spray cone angle was measured by using shadow graphy method. As a result when the injection pressure was increased, mean drop size was decreased. And the dominant factor which influence on the spray characteristics of pressure swirl atomizer was orifice diameter.

• Journal of Mechanical Science and Technology
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• 제16권4호
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• pp.572-579
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• 2002

The experimental measurements were carried out to examine turbulent disintegration characteristics ejecting from a counter-flowing internal mixing pneumatic nozzle under variable conditions of swirl angles and air pressures. The air injection pressure was varied from 60 kPa to 180 kPa and four counter-flowing internal mixing nozzles with axi-symmetric tangential-drilled holes at swirl angle of 15$^{\circ}$, 30$^{\circ}$, 45$^{\circ}$, and 60$^{\circ}$to the central axis have been specially designed. The experimental results were quantitatively analyzed, focusing mainly on the comparison of turbulent atomization characteristics issuing from an internal mixing swirl nozzle. To illustrate the swirl phenomena, the distributions of mean velocities, turbulence intensities, volume flux, and SMD (Sauter Mean Diameter, or D$\sub$32/) were comparatively analyzed.

• 한국연소학회:학술대회논문집
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• 한국연소학회 2001년도 제22회 KOSCI SYMPOSIUM 논문집
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• pp.67-74
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• 2001

The annular-reverse combustor was designed for APU combustor and a three dimensional analysis for reactive flow in the combustor was performed. At the same time, the experimental work was performed in KARl combustor test facility. In this study we found out that tangential swirl type combustor is good for flame holding than single vortex type combustor. The flame tube main hole size and relative position are very important parameters for combustor general performance. The ignition characteristics are strongly depend on the air fuel ratio with combustor inlet volume flow ratio.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2008년도 제30회 춘계학술대회논문집
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• pp.115-118
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• 2008

지금까지 액막두께나 air core 직경 변화 등과 같은 수력학적 과정에 대한 이론 실험적 연구가 많이 이루어져왔다. 스월 노즐에서 수치적 해석 등을 통해 이에 대한 몇 가지 이론식들이 확립되었지만, 아직까지 내부유동에 대한 실험적 연구 결과 등은 명백히 정립되어 있지 않고 있다. 본 연구에서는 스월 챔버 내의 air core를 가시화하고 액막두께를 측정하여 내부유동의 변화 및 안정성 등을 살펴보았다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.125-130
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• 2001

Experimental and analytical researches have been conducted on the twin-fluid atomizers for better droplet breakup during the past decades. But, the studies on the disintegration mechanism still present a great challenge to understand the drop behavior and breakup structure. In an effort to describe the aerodynamic behavior of the sprays issuing from the internal mixing counter-swirling nozzle, the spatial distribution of axial (U) radial (V) and tangential (W) components of droplet velocities are investigated across the radial distance at several axial locations of Z=30, 50, 80, 120 and 170mm, respectively. Experiments were conducted for the liquid flow rates which was kept constant at 7.95 g/s and the air injection pressures were varied from 20 kPa to 140 kPa. Counter-swirling internal mixing nozzles manufactured at angles of $15^{\circ},\;30^{\circ},\;45^{\circ}$ and $60^{\circ}$ the central axis with axi-symmetric tangential-drilled holes was considered. The distributions of velocities and turbulence intensities are comparatively analyzed. PDPA is installed to specify spray flows, which have been conducted along the axial downstream distance from the nozzle exit. Ten thousand of sampling data was collected at each point with time limits of 30 second. 3-D automatic traversing system is used to control the exact measurement. It is observed that the sprays with all swirl angle have the maximum SMD for on air injection pressure of 20 kPa and 140 kPa with centerline, respectively. The nozzle with swirl angle of $60^{\circ}$ has vest performance.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2007년도 제28회 춘계학술대회논문집
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• pp.7-12
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• 2007

액체로켓엔진에서 고주파 연소불안정을 제어하기 위하여 다단 접선 유입구를 갖는 스월 인젝터를 분석하였다. 음향흡수자로서 인젝터의 효과를 분석하기 위하여 인젝터는 1/4 파장 공명기로 해석하였고, 상온에서 감쇠 효과의 적합성을 검증하였다. 이러한 인젝터는 모델 챔버의 고유주파수에 동조 시킬 수 있는 고유주파수를 갖게 된다. 각각의 모드에 동조된 인젝터를 배(anti-node point)에 장착하여야만, 타겟모드의 진폭을 감소시킬 수 있었고, 큰 지름의 인젝터를 사용하였을 때 보다 큰 진폭의 감쇠를 동반하면서 모드 분리 현상이 나타났다. 이러한 실험 결과로부터 타겟모드에 동조된 인젝터를 적당한 볼륨으로 배(anti-node point)에 장착한다면, 모드 진폭이 감쇠하게 되고, 완전한 배(anti-node point)에서는 모드분리현상이 발생됨을 확인하였다.

• 한국분무공학회지
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• 제11권4호
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• pp.212-219
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• 2006

The initial film flow development of the high-pressure swirl spray was investigated at different injector operating conditions to analyze film flow development and to provide the input data for the modeling works. This result can be also useful to verify the previously simulated results. The initial flow conditions such as liquid film thickness, flow angle and flow divergence are obtained by visualizing the inside and near the nozzle flow with a microscopic imaging system. The visualized images are quantified using an image processing tool. From the information of liquid film thickness and flow angle, the initial axial and tangential velocity and the swirl number of the swirl spray are successfully determined at various operating conditions. The experimental results showed that the initial liquid film thickness, flow angle and flow divergence are remained constant when the injection pressure is increased. However, initial film conditions are severely changed when the fuel temperature is increased. The swirl number remained constant when the injection pressure is increased while it showed increased value at high fuel temperature condition.