Propulsion Aspects of Hypersonic Turbo-Ramjet-Engines With Special Emphasis on Nozzle/Aftbody Integration

Herrmann, Hans–Georg; Rick, Hans

doi:10.1115/91-gt-395

Cited by 32 publications

(8 citation statements)

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“…Researchers have been testing different nozzle systems in scramjet engines in order to increase the thrust of the vehicle [3,4]. Single expansion ramp nozzle is a very essential component in scramjet vehicles to produce most of the thrust [5]. Hirschen et al [6] have investigated the performance of the single expansion ramp nozzle at different flight altitudes and run conditions by varying the Reynolds number, nozzle pressure ratio and the heat capacity ratio, and pressure measurements and Schlieren photographs were employed to study the effect of the capacity ratio on the interactions between the external and the nozzle flows.…”

Section: Introductionmentioning

confidence: 99%

Performance Enhancement of Single Expansion Ramp Nozzle in Scramjets

Yerra¹

2019

IJRASET

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Single expansion ramp nozzle is a type of nozzle which is mostly used for higher thrust in scramjet engines. This study is a numerical analysis on the production of thrust with the help of a simple expanded ramp nozzle. In this analysis, thrust at different lengths and angles of cowl and ramp were compared to bring the optimized configuration of the nozzle. CFD simulation has been used for the analysis. RNG K-Ɛ model was used to solve the solve the Navier-Stokes equation. The length of the inner nozzle, the external ramp and the internal cowl length are the main parameters in the performance of the thrust and the lift.

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Section: Introductionmentioning

confidence: 99%

Performance Enhancement of Single Expansion Ramp Nozzle in Scramjets

Yerra¹

2019

IJRASET

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“…2. The afterbody of the vehicle is a part of the SERN which offers a good integration into the aircraft and have a certain self-adapt ability at off-design operation (1) . The TBCC engine uses the turbojet propulsion part from take-off to approximately Mach 4, then the engine transfers to the ramjet/ scramjet propulsion system for the increased velocities (2) .…”

Section: Introductionmentioning

confidence: 99%

Numerical investigation of separation pattern and separation pattern transition in overexpanded single expansion ramp nozzle

et al. 2014

Aeronaut. j. (1968)

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Flow separation results in many problems to single expansion ramp nozzle (SERN) and hypersonic vehicle. However, little research has been conducted on the separation patterns and their effects on SERN’s performance. In the present paper, the numerical simulation is adopted to get the intuitive results and help to analyse the separation phenomena in SERN thoroughly. The main separation pattern is the restricted shock separation (RSS) in SERN, and the free shock separation (FSS) only appears in a small range of the nozzle pressure ratio (NPR), which is much different from the axisymmetric rocket nozzle. Further CFD results show that the separation pattern transition makes great effects on the performance of SERN, especially the lift. Moreover, the performance of SERN has an extreme in the separation pattern transition because of the main jet impinging on the expansion ramp. The transitions occur in both the startup and shutdown processes but the critical nozzle pressure ratios of the separation pattern transitions are different, which leads to a hysteresis loop of SERN performance.

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“…Hypersonic vehicles require a high level of integration between airframe and propulsion systems, those that uses air-breathing propulsion based on scramjet engines have a close interaction with vehicle stability as well [5][6][7][8]. Furthermore, inlet and nozzle components generally are fused within vehicle forebody and afterbody, respectively, influencing thrust efficiency and vehicle trimmability [9][10][11].…”

mentioning

confidence: 99%

“…SERN is used to minimize the frictional drag and nozzle weight while taking out most of the thrust from the high-pressure flow on the afterbody [6,14]. Moreover, SERN enhances the internal/external integration level for hypersonic vehicles [9] and has the ability to adapt automatically to variations in environmental static pressure while in the off-design conditions [7]. However, when the operation conditions (pressure, Mach number, angle of attack, and mostly when the engine is started or turned off) vary drastically, changes in lift and pitch moment are inevitably.…”

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confidence: 99%

Experimental Study of Single Expansion Ramp Nozzle Performance Using Pitot Pressure and Static Pressure Measurements

Laitón

Martos

Rêgo³

et al. 2019

International Journal of Aerospace Engineering

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In order to overcome the drag at hypersonic speed, hypersonic flight vehicles require a high level of integration between the airframe and the propulsion system. Propulsion system based on scramjet engine needs a close interaction between its aerodynamics and stability. Hypersonic vehicle nozzles which are responsible for generating most of the thrust generally are fused with the vehicle afterbody influencing the thrust efficiency and vehicle stability. Single expansion ramp nozzles (SERN) produce enough thrust necessary to hypersonic flight and are the subject of analysis of this work. Flow expansion within a nozzle is naturally 3D phenomena; however, the use of side walls controls the expansion approximating it to a 2D flow confined. An experimental study of nozzle performance traditionally uses the stagnation conditions and the area ratio of the diverging section of the tunnel for approaching the combustor exit conditions. In this work, a complete hypersonic vehicle based on scramjet propulsion is installed in the test section of a hypersonic shock tunnel. Therefore, the SERN inlet conditions are the real conditions from the combustor exit. The performance of a SERN is evaluated experimentally under real conditions obtained from the combustor exit. To quantify the SERN performance parameters such as thrust, axial thrust coefficient C f x and lift L are investigated and evaluated. The generated thrust was determined from both static and pitot pressure measurements considering the installation of side walls to approximate 2D flow. Measurements obtained by a rake show that the flow at the nozzle exit is not symmetric. Pitot and pressure measurements inside the combustion chamber show nonuniform flow condition as expected due to side wall compression and boundary layer. The total axial thrust for the nozzle obtained with the side wall is slightly higher than without it. Static pressure measurements at the centerline of the nozzle show that the residence time of the flow in the expansion section is short enough and the flow of the central region of the nozzle is not altered by the lateral expansion when nozzle configuration does not include side walls.

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Propulsion Aspects of Hypersonic Turbo-Ramjet-Engines With Special Emphasis on Nozzle/Aftbody Integration

Cited by 32 publications

References 0 publications

Performance Enhancement of Single Expansion Ramp Nozzle in Scramjets

Performance Enhancement of Single Expansion Ramp Nozzle in Scramjets

Numerical investigation of separation pattern and separation pattern transition in overexpanded single expansion ramp nozzle

Experimental Study of Single Expansion Ramp Nozzle Performance Using Pitot Pressure and Static Pressure Measurements

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