• Title/Summary/Keyword: 스월각

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가스터어빈 트랜지션 덕트 내에서 스월각이 손실계수에 미치는 영향에 대한 연구

  • 임찬선;전승배;김승우
    • 유체기계공업학회:학술대회논문집
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    • 1998.02a
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    • pp.150-156
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    • 1998
  • 가스터어빈 트랜지션 덕트 내에서의 공기 역학적인 거동을 입구 스월각의 변화에 대하여 고찰하였다. 트렌지션 덕트가 작은 확산각(divergence angle)을 가지더라도 스트럿 영향으로 인한 탈설계점에서의 유동 패턴은 트랜지션 덕트 내에서의 유동특성을 더욱 악화시킨다. 시험범위의 스월각은 마하수 변화에 따라 손실계수에 큰 영향을 주지 못하였으며 트랜지션 덕트 내에서의 손실 정조는 만족할만 하나, 시험결과에 따르면 저압터빈의 노즐손실은 큰 입사각의 영향으로 커질것으로 생각되며, 또한 스트럿으로부터 떨어져 나오는 와류는 저압터빈의 로우터 블레이드의 진동에 악영향을 미칠 것으로 생각된다.

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Influence of Fuel Swirl Flow on NOx Emission in Swirl Combustor (스월연소기에서 연료스월유동이 NOx 배출에 미치는 영향)

  • Cho, Jin-Woo;Whang, Sang-Ho;Choi, Gyung-Min;Kim, Duck-Jool
    • 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.

Effect of Backhole on Spray Characteristics of Swirl Injectors in Liquid Propellants Rocket Engine (액체 추진제용 로켓 엔진 스월 인젝터의 백홀로 인한 분무 특성 연구)

  • 황성하;윤영빈
    • Journal of the Korean Society of Propulsion Engineers
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    • v.7 no.2
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    • pp.23-35
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    • 2003
  • "Backhole" is a new geometric parameter and is defined as an extra empty volume which is located behind the tangential entries at the rear part of the vortex chamber in the swirl injector. Backhole makes a difference to the spray characteristics of swirl injectors such as the spray angle, SMD, the mixing characteristics and so on. To find its characteristics, experiments are conducted by using a stroboscopic photography, a PDPA apparatus and a mechanical patternator. With the backhole, the mass flow rate of the swirl injector is increased and the center region of the injected flow has more large volume than that of without the backhole. Also the cone angle can be controlled by the backhole, so that the mixing efficiencies of swirl injectors are changed. Based on cold-flow tests, the swirl injector with the backhole may improve its performance.rformance.

Spray Characteristics of Closed-type Swirl Injectors with Varying Swirl Chamber Geometry (Closed-type 스월 인젝터의 스월 챔버 형상에 따른 분무특성 연구)

  • Chung, Yunjae;Jeong, Seokkyu;Oh, Sukil;Yoon, Youngbin
    • Journal of the Korean Society of Propulsion Engineers
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    • v.19 no.4
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    • pp.8-14
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    • 2015
  • This study has been done as a preliminary work in the process of confirming the modeling and calculation results on the dynamic characteristics of closed-type swirl injector which were performed by Ismailov et al. in Purdue university. Closed-type swirl injectors with replaceable swirl chamber parts were designed and manufactured. The steady state spray characteristics of closed-type swirl injector with varying swirl chamber length and diameter were verified. Mass flow rate was measured with a mass flow meter installed in front of the injector, and liquid film thickness was measured by Lefebvre's method with electrodes installed at the orifice of the injector. Variation of spray cone angle and break-up length were investigated from the spray images captured under different manifold pressure conditions.

Spray characteristics of swirl injector using liquid film thickness measurement (액막두께 측정방법을 이용한 스월 인젝터의 분무특성 연구)

  • Kim Sung-Hyuk;Kim Dong-Jun;Kim Byung-Sun;Yoon Young-Bin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2005.11a
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    • pp.251-255
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    • 2005
  • By using liquid film thickness measurement the spray characteristics of swirl injector according to the geometric parameters were investigated in this paper. A specially designed injector having a variable backhole length, swirl chamber length, orifice length was used to measure the liquid film thickness. The spray characteristics of the injector were represented by mass flow rate according to the injection pressure, liquid film thickness in the lower orifice, spray cone angle.

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Experimental Study on Mixing Efficiency of Exhaust Gas and Reductant According to SCR Mixer Shape (SCR 믹서형상에 따른 배기가스와 환원제 혼합 효율에 관한 실험적 연구)

  • Choe, Munseok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.22 no.3
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    • pp.74-79
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    • 2021
  • This study examined the mixing efficiency of exhaust gas and urea according to the mixer shape in the SCR system. For the experiment, an SCR simulation system was manufactured, and a uniformity detector was attached to the catalyst location to measure the uniformity. The experiment was conducted by setting the exhaust-gas flow rate, temperature, mixer type, and catalyst distance as variables. The experimental results confirmed the swirl angle analysis, urea number distribution, and uniformity. The swirl angle experiment of Models A and B confirmed that the swirl angle of Model A was formed approximately 7 to 8 degrees higher over the entire RPM range. When there was no mixer in the SCR system, the urea and water were concentrated to one side. Mixer Model A showed an even distribution overall, and Model B showed a slightly concentrated tendency at the beginning but then showed a stable distribution of urea. The mixing efficiency of 90%, which was the uniformity target, could be satisfied in Model A and Model B. In particular, Model A showed excellent results that satisfied 90% efficiency at 10 cm of the catalyst position.

A study on flame bifurcation due to inlet mixture temperature and swirl strength in a swirl turbulent combustor (스월 난류연소기의 흡입공기온도, 스월세기에 따른 연소불안정 발생 메커니즘에 대한 연구)

  • Kim, Jong-Chan;Sung, Hong-Gye;Ryu, Hyeok
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2007.11a
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    • pp.377-380
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    • 2007
  • Large Eddy Simulation has been conducted to investigate both stable and unstable flame structures in a swirl turbulent combustor. While a flame is stabilized with periodic dynamic structure at 600K, a slight increase in the flame temperature of inlet mixture, 660K, lead to bifurcation of flame at swirl angle 45 degrees. It was observed that both swirl number and mixture temperature affect a flame bifurcation and the former is a major parameter. One major mechanism contributing to the unstable flame is that the local flame speed overshadows the local flow velocity near the wall of the combustor.

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Spray Breakup Characteristics of a Swirl Injector in High Pressure Environments (고압환경에서 스월 인젝터의 분무 및 분열특성)

  • 김동준;윤영빈;임지혁;길태옥;한풍규
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.7
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    • pp.97-104
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    • 2006
  • The spray and breakup characteristics of swirling liquid sheet were investigated by measuring the spray angle and breakup length as the axial Weber number Wel was increased up to 1554 and the ambient gas pressure up to 4.0MPa. As Wel and ambient gas density increased, the disturbances on the annular liquid sheet surface were amplified by the increase of the aerodynamic forces, and thus the liquid sheet disintegrated near from the injector exit. The measured spray angles according to the ambient gas density were different before and after the sheet breaks. Before the liquid sheet breaks, the spray angle was almost constant, but once the liquid sheet started to breakup, the spray angle decreased. And the breakup length decreased because of the increase of the aerodynamic force as the ambient gas density and Wel increased. Lastly, the measured breakup length according to the ambient gas density and Wel was compared with the result by the linear instability theory. We found that the corrected linear instability theory considering the attenuation of sheet thickness agrees well with our experimental results.

Spray Characteristics According to the Variation of Design Parameters and Gas-liquid Momentum-flux Ratio in a Swirl-coaxial Injector Applied to Small Rocket Engine (소형로켓엔진에 적용된 스월 동축형 인젝터의 형상변수와 기체-액체 운동량 플럭스 비에 따른 분무특성)

  • Hyun Jong Ahn;Yun Hyeong Kang;Jeong Soo Kim
    • Journal of the Korean Society of Propulsion Engineers
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    • v.27 no.1
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    • pp.27-36
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    • 2023
  • To understand the atomization performance in gas-liquid swirl-coaxial injector applied to a small rocket engine, a cold-flow test was performed by varying the design parameters and supply condition of propellants. As the swirl-chamber diameter and the angle of the convergent section, which are design parameters of injector increased, the spray performance of the injector improved by increasing the swirl strength. In addition, as the gas-liquid momentum-flux ratio increased, the gas flow separated some of the droplets from the liquid film, and a gas-droplet mixture core was formed in the center of the spray sheet.

Spray Characteristics of a Liqud-Liquid Swirl Coaxial Injector (액체-액체 스월 동축형 인젝터의 분무특성)

  • Kim Dong-Jun;Im Ji-Hyuk;Han Poong-Gyoo;Yoon Young-Bin
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2006.05a
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    • pp.147-150
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    • 2006
  • The influences of injection conditions and recess configuration of liquid-liquid swirl coaxial injector on spray characteristics were investigated. The characteristics of the coaxial spray in internal mixing injection region were mai y controlled by the merging phenomenon and momentum balance between two liquid sheets, but those in internal mixing injection region were influenced by the impingement phenomenon as well as momentum balance between two liquid sheets.

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