• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.47 no.12
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• pp.848-855
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• 2019

Eco-friendly gas turbine combustors are getting attention due to emission regulations. Swirler is important design factor for flame stability and flashback inside the combustor. Design methods of the axial swirler and the radial swirler were discussed and the suitability of the swirl number calculation considering the geometric design variables and the flow loss was examined in the radial swirl for gas turbine combustor. The swirl number of flow was calculated by computational fluid dynamics and compared with swirl number according to each design method.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2010.05a
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• pp.14-17
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• 2010

To identify the turbulent flow characteristics resulted from the swirl direction of a combustor with seven swirl injectors, a 3D Large Eddy Simulation(LES) was implemented. The combustor of concern is the LRE combustor, designed by Aerospace Combustion Laboratory of Georgia Institute of Technology. The seven-clockwise-swirl-injectors combustor produces stronger flow interference among injectors, specially obvious tangential velocity near the wall, than the combustor with four-clockwise and three-counterclockwise swirl injectors. In addition, pressure fluctuations in the combustor with seven-clockwise-swirl-injectors was more amplified.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2011.11a
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• pp.445-450
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• 2011

Swirling flows inside a swirl mixing chamber are investigated for simple configuration where swirl is produced by a tangential entry type swirl generator. The flow downstream of the swirl generator has been quantified by measurements two velocity components and their corresponding mean values along axial and radial direction using Particle Image Velocimetry(PIV). The mass flow rate of the tangential entry is increased in order to study their effect on the flow field. From the measurement profile of velocity and vorticity, flow mixing characteristics in a swirl mixing chamber are evaluated.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.48 no.1
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• pp.43-53
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• 2020

The effect of the relative location between pre-swirl nozzle and receiver hole on the performance of radial on-board injection type pre-swirl system was analyzed. In this study, tendency of the change of discharge coefficient and temperature drop efficiency were analyzed for 20 design points through the combination of 5 pre-swirl nozzle location and 4 receiver hole location. Discharge coefficient of system tended to be similar to the pressure ratio of the pre-swirl nozzle. System performance variation occurred as the flow structure in the cavity was affected by the surface, and the influence of the stationary surface is greater than that of the rotating surface. Discharge coefficient of system changed -1.39% to 1.25% and temperature drop efficiency changed -5.41% to 2.94% refer to reference design point.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2002.04a
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• pp.6-7
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• 2002

동축형 인젝터는 이미 여러 발사체에서 널리 쓰이고 있는 인젝터의 한 형태로서 또 다른 인젝터 방식인 충돌형과 비교하여 구조가 복잡한 단점이 있는 반면에 연소 현상의 불안정성에 대해 덜 민감하며 미립화와 혼합의 특성도 우수하다. 이런 동축형 인젝터는 크게 스월 방식과 shear 방식으로 나누어진다. 이중에서 스월 인젝터는 산화제와 연료의 유입구에 접선 방향의 속도를 줌으로써 conical sheet 형태의 분무장을 형성하여 미립화와 혼합을 꾀하는 방식이다. 이와 같은 스월 인젝터에서 중요한 변수 중에 하나인 recess의 변화에 대해 분무 형상과 미립화 혼합특성까지 파악해보았다.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.30 no.4
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• pp.70-76
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• 2002

Characteristics of kerosine spray combustion were investigated at various swirl condition. PDPA(Phase Doppler Particle Analysis) was used to measure the droplet sizes and velocities. R-type(Platinum vs. Platinum-13%rhodium) thermocouple was used to measure the temperature of combustion flow field inside model combustor. A visualization of spray and flame was performed with still camera. As swirl number increases due to increase of swirl vane angle, the spray and the flame were developed to radial direction rapidly. When swirl number is small, the configuration of flame is cone type, but swirl number is large, the configuration of flame is cylindrical type due to enhanced mixing by the transport of swirl momentum.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.7
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• pp.70-75
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• 2005

In this study, experimental investigations were conducted on NOx emission characteristics with fuel swirl flow in swirl combustor. Many types of vanes, which altered air and fuel swirl angles, were employed to verify the mixing processes. For strong air swirl, fuel counter-swirl resulted in relatively large turbulent intensity, high energy to the high frequency region and narrow width of high temperature region compared with co-swirl condition. These effects of fuel counter-swirl resulted in low NOx emission characteristics at strong air swirl condition. And NOx reduction mechanism was also discussed.

• Journal of the Korean Society of Propulsion Engineers
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• v.12 no.6
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• pp.30-37
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• 2008

Many theoretical and experimental studies have been conducted to investigate elements of swirl injector hydrodynamics, such as variations in liquid film thickness or air core diameter. From these studies, some theoretical relationships have been established through an approximate analytical solution of flow hydrodynamics in a swirl nozzle. However, experimental studies on elements such as the stability of internal flow have not produced conclusive results. In this study, the stability of the internal flow under tangential entry conditions was examined by visualizing the formation of the air core in the swirl chamber and measuring the liquid film thickness in the orifice.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.115-118
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• 2008

Many theoretical and experimental studies have been conducted to investigate elements of the hydrodynamic process, such as variations in liquid film thickness or air core diameter. From these studies, some theoretical relationships have been established through an approximated analytical solution of flow hydrodynamics in a swirl nozzle. However, experimental studies on elements such as internal flow have not produced conclusive results. In this study, the variations and stability of the internal flow were examined by visualizing the air core and measuring the liquid film thickness.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 2008.05a
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• pp.77-81
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• 2008

The local regression rate behavior of solid fuel in swirl injection hybrid rocket were studied. In generally, axial injection regression rate was tending to be decrease with axial distance, beyond which increased with increasing axial distance from the leading edge. On the other hand, swirl injection regression rate was high at the leading edge of the fuel and comparatively uniform regression rate at the downstream. Overall regression rate of swirl injection was increased about 54% for the overall regression rate of axial injection. Through this study, it was found that using swirl injector was useful in applying to the small sounding rocket.