• Title/Summary/Keyword: 초음속유동

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Study on the Surface Heat Transfer Around a Circular Secondary Jet in the Supersonic Flow (초음속 유동내 원형 2차분사 제트 주변에서의 표면 열전달 현상 연구)

  • Yi, Jong-Ju;Yu, Man-Sun;Cho, Hyung-Hee
    • Journal of the Korean Society of Propulsion Engineers
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    • v.11 no.2
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    • pp.47-53
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    • 2007
  • Convective heat transfer coefficient was measured around a circular secondary jet ejected into the supersonic flow field. The wall temperature measurement around a injection nozzle was conducted using infra-red camera. The constant heat flux is applied to the wall around a secondary nozzle. According to jet to freestream momentum ratio, the injection flow penetrates into the supersonic flow field. The measured temperature is used to calculate the convective heat transfer coefficient.

CFD Investigation of Rocket Nozzle Plume for Flame Deflector Preliminary Analysis (화염유도로 예비 해석을 위한 로켓노즐 플룸의 CFD 해석 검증)

  • Jun, Doo-Sung;Kim, Jae-Woo;Kim, Jong-Rok;Kim, Woo-Kyeom;Kim, Seung-Cheol;Moon, Hee-Jang
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2011.11a
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    • pp.313-316
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    • 2011
  • This paper investigates CFD investigation on single phase supersonic nozzle flow and 2-phase subson ic flow prior to rocket nozzle supersonic 2-phase flow with water injection within the flame deflector. Numerical results of supersonic nozzle single phase flow showed no notable unrealistic behavior as it captures the usual shock cell structures. Three-dimensional 2-phase flow analysis has also been performed to verify whether the approach can grab the droplet behavior during cooling by water injection. It is expected these basic studies will enhance the cooling problem analysis of supersonic 2-phase rocket plume in the future.

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Study of The Air Jet Normally Injected into Supersonic Stream (초음속 자유유동에 수직으로 분사되는 제트유동장에 관한 연구)

  • 구병수;김희동
    • Journal of the Korean Society of Propulsion Engineers
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    • v.4 no.4
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    • pp.42-49
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    • 2000
  • A computation using the mass-averaged implicit Wavier-Stokes equations has been applied to solve the flow fields of the supersonic jets normally injected into supersonic freestreams and several types of turbulence model has been employed to close the governing equations. The ratio of the freestream to injection flow total pressures has been varied to elucidate the major characteristics of the mixing flow of the two streams. The freestream Mach number has been varied to investigate some change in the injection flow field. The results show that the positions of the separation and reattachment, locating upstream and downstream of the injection hole respectively, are strongly dependent on the ratio of total pressures and the freestream Mach number.

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Structural Change of Supersonic Jet Due to Liquid Injection in Supersonic Backward Facing Step Flow (초음속 후향 계단 유동에서 액체 분사로 인한 초음속 제트의 구조 변화)

  • Ahn, Sang-Hoon;Han, Doo-Hee;Choi, Han-Young;Seo, Seong-Hyeon;Sung, Hong-Gye
    • Journal of Aerospace System Engineering
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    • v.13 no.6
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    • pp.9-16
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    • 2019
  • The experiment on the liquid jet in crossflow in supersonic BFS (backward-facing step) flow was conducted to investigate the mixing characteristics. The working fluids are nitrogen and water. The shadow graph technique was used to visualize the flow field. Images captured by the high-speed camera were applied to analyze the flow phenomena. The liquid jet was injected at the re-circulation zone created by the supersonic jet flow. Experimental conditions are defined based on the pressure of the nitrogen gas chamber and pressurized liquid tank. In respective cases, the penetration depth of liquid jet and location of the Mach disc were observed to be proportional to the momentum ratio of gas and liquid jets.

An Experimental Study on the Supersonic Free Jet Discharged from a Petal Nozzle (Petal 노즐로부터 방출되는 초음속 자유제트에 관한 실험적 연구)

  • 이준희;권용훈;정미선;이장창;김희동
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2002.04a
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    • pp.55-56
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    • 2002
  • 노즐로부터 방출되는 초음속 제트유동의 특성은 노즐의 공급압력과 배압의 비에 따라 결정된다 노즐 배압에 상대적인 노즐 출구면에서 발생하는 압력의 크기에 따라 제트 유동은 과팽창, 적정팽창, 그리고 부족팽창의 형태로 된다. 종래 주로 단면이 원형인 초음속 노즐로부터 방출되는 자유제트에 관하여 많은 연구가 수행되어, 제트 유동의 특성이 비교적 잘 알려져 있다. 이들 연구 결과에 의하면, 제트 내부에서 발생하는 충격파 시스템은 노즐 출구면에서 유동의 팽창상태에 의존하게 되며, 제트 유동은 주위의 기체를 흔입(entrainment)하여, 유동의 하류방향으로 제트 폭이 확대되며, 유속은 감소하게 된다.

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Study on Design Parameters of Supersonic Ejectors to Simulate High Altitude Engine Test (고고도 엔진 성능모사를 위한 2차 노즐 목을 갖는 초음속 이젝터의 설계 인자 연구(Ⅱ))

  • Yoon, Si-Kyung;Yeom, Hyo-Won;Sung, Hong-Gye;Shin, Wan-Soon
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2008.11a
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    • pp.353-356
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    • 2008
  • The effects of design parameters of supersonic ejector system under the assumption of constant pressure mixing; such as mass flow rate ratio, area ratio, Primary mach number on ejector system performance were investigated by theoretical formulations. And for a given design condition and working fluid, Computational Fluid Dynamics was conducted.

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Experimental Study on the Flow Hysteresis Phenomenon in a Supersonic Nozzle (초음속 노즐에서 발생하는 유동 이력현상에 대한 실험적 연구)

  • Nam, Jong-Soon;Kim, Heuy-Dong
    • Journal of the Korean Society of Propulsion Engineers
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    • v.16 no.2
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    • pp.58-64
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    • 2012
  • Hysteresis phenomena in fluid flow systems are frequently encountered in many industrial and engineering applications and mainly appear during the transient processes of change of the pressure ratio. Shock-containing flow field in supersonic nozzles is typically subject to such hysteresis phenomena, but associated flow physics is not yet understood well. In the present study, experimental work has been carried out to investigate supersonic nozzle flows during the transient processes of change in the nozzle pressure ratio. Time-dependent surface wall pressures were measured by a multiple of pressure transducers and the flow field was visualized using a nano-spark Schlieren optical method. The results obtained show that the hysteresis phenomenon is strongly dependent on the nozzle geometry as well as the time scale of the change of pressure ratio.

Unsteady Separation Characteristics of Air-Launching Rocket from Full-Geometry Mother Plane (초음속 공중발사를 위한 전기체-로켓의 비정상 분리 유동특성)

  • Ji, Young-Moo;Byun, Yung-Hwan;Park, Jun-Sang;Lee, Jae-Woo
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.35 no.6
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    • pp.474-482
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    • 2007
  • An analysis is made for flow and rocket motion during a supersonic separation stage of an air-launching rocket(ALR) from the mother plane. Three-dimensional compressible Navier-Stokes equations are numerically solved to analyze the steady/unsteady flow fields around the rocket which is being separated from the mother plane configuration(F-4E Phantom). Simulation results clearly demonstrate the effect of shock-expansion wave interaction around both of the rocket and the mother plane. To predict the behavior of the ALR by the change of the center-of-gravity, three cases of numerical analysis are performed. As a result, a design-guideline of supersonic air-launching rockets for safe separation is proposed.

Study on the Flow Characteristics of Supersonic Air Intake at Mach 4 (마하4 초음속 공기 흡입구 유동 특성에 관한 연구)

  • ;;;;Shigeru , Aso
    • Journal of the Korean Society for Aeronautical & Space Sciences
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    • v.34 no.10
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    • pp.61-70
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    • 2006
  • A Supersonic air intake model was designed for the high performance ramjet and dual-mode scramjet engine to operate at Mach 4 flight condition. The air intake was tested in the blowdown-type wind tunnel of Kyushu University to identify the internal flow characteristics corresponding to the flight parameters such as the back pressure, angle of attack and angle of yaw. Flow visualization was achieved by the Schlieren and oil flow visualization techniques. The intake performance was analyzed quantitatively based on the surface pressure and total Pressure measurements. The experimental results were compared with the computational fluid dynamics results. The present study exhibits the fundamental but rarely found experimental results of the high Mach number supersonic air intake.

An Experimental Study on the flow Characteristics of a Supersonic Turbine Cascade as the Leading Edge Shape and the Nozzle-Cascade Cap (초음속 터번 익렬 앞전 형상 및 노즐-익렬 간격에 따른 유동 특성에 대한 실험적 연구)

  • Cho Jong-Jae;Kim Kui-Soon;Kim Jin-Han;Jeong Eun-Hwan;Jeong Ho-Kyung
    • Journal of the Korean Society of Propulsion Engineers
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    • v.9 no.4
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    • pp.66-72
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    • 2005
  • In this paper, a small supersonic wind tunnel is designed and built to study the flow characteristics of a supersonic impulse turbine cascade. The flow is visualized by means of a single pass Schlieren system. The supersonic cascade with 2-dimensional supersonic nozzle was tested for various blade leading edge shapes and gaps between the nozzle and cascade. Highly complicated flow patterns including shocks, nozzle-cascade interaction and shock boundary layer interactions are observed.