Dual-expander engine flowfield simulations

Hagemann, G.; Krülle, G.; Manski, D.

doi:10.2514/6.1995-3135

Cited by 5 publications

(13 citation statements)

References 1 publication

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“…A typical vertical velocity component at this altitude of existing launchers is approx. v(h) = 300 m/s [5]. The comparison of the Schmucker-criterion with available experimental data results in a deviation of experimental and theoretical data of S re i tU = <5 re /,/ « 8% , which finally results in a duration of the transitional phase, according to Eq.…”

Section: Nozzle Extension With Positive Wall Pressure Gradient ("Overmentioning

confidence: 97%

“…Thus, the flow separates on one side of the nozzle at the lower separation wall pressure p w (l -8 Te i,i), and on the opposite nozzle wall at the upper separation wall pressure p w (l + 6 re i, u )-The projection of the tilted separation line on a plane normal to the side load direction is assumed to have an elliptic form. Further details can be found in [5]. The interpretation of Eq.…”

Section: Nozzle Extension With Positive Wall Pressure Gradient ("Overmentioning

confidence: 97%

“…As an example of the flowfield of a dual-bell nozzle, Fig. 4 shows temperature isolines in the altitude mode and a phenomenological sketch [5]. Compression waves are induced near the throat, emanating downstream towards the axis.…”

Section: Flow Phenomena In Dual-bell Nozzlesmentioning

confidence: 99%

“…The pressure drop across this wall inflection can be estimated with the equations for the Prandtl-Meyer expansion [5]. To ensure flow separation at the wall inflection down to the desired ambient pressure value, the wall pressure value behind the wall inflection can be estimated with commonly used separation criteria, like Summerfield [10], Schmucker [9], or tabulated data as used by Aerojet [6].…”

Section: Wall Inflection and Nozzle Extensionmentioning

confidence: 99%

“…First numerical simulations were performed for the reference bell nozzle with the numerical scheme AS3D [4], and for verification also with the numerical schemes NSHYP [3] and TDK [7]. The further numerical simulations of the dual-bell nozzles were performed with AS3D [4], [5], With regard to the numerical simulations of dual-bell nozzles, AS3D has been validated with experimental data of overexpanding conventional nozzles, and with experimental data of the Rocketdyne experiment on dual-bell nozzles, see [4] for further details. Further test case simulations were performed on rather simple flow conditions, where analytical solutions exist, e. g. Prandtl-Meyer expansion around an edge.…”

Section: Parametrical Variation Of Dual-bell Nozzle Design Parametersmentioning

confidence: 99%

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A critical assessment of dual-bell nozzles

Hagemann¹,

Frey²,

Manski³

1997

33rd Joint Propulsion Conference and Exhibit

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A critical assessment of dual-bell nozzles is given in this paper. First, the principle flowfield development in dual-bell nozzles is discussed. Design aspects for the contour of the base nozzle, the wall inflection and of the nozzle extension are discussed. Special regard is focussed on the transition behaviour from sea-level to vacuum operation and its dependence on the contour type used for the nozzle extension.Performance results of parametric numerical simulations of dual-bell nozzles are presented. These calculations, which give an insight into the additional performance losses caused by the dual-bell nozzle contour, were performed within the ESA-contract FESTIP on advanced space transportation concepts. The necessity of further experimental investigations on dual-bell nozzles is highlighted, which will lead to a better understanding of the flow transition in dual-bell nozzles.Finally, some ideas are discussed for an additional influence on the transition behaviour on system level, by varying the chamber pressure to ensure a sudden and controlled jump of the separation point from the wall inflection (sea-level operation) to the exit plane (vacuum operation) and to improve performance.

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Section: Nozzle Extension With Positive Wall Pressure Gradient ("Overmentioning

confidence: 97%

Section: Nozzle Extension With Positive Wall Pressure Gradient ("Overmentioning

confidence: 97%

Section: Flow Phenomena In Dual-bell Nozzlesmentioning

confidence: 99%

Section: Wall Inflection and Nozzle Extensionmentioning

confidence: 99%

Section: Parametrical Variation Of Dual-bell Nozzle Design Parametersmentioning

confidence: 99%

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A critical assessment of dual-bell nozzles

Hagemann¹,

Frey²,

Manski³

1997

33rd Joint Propulsion Conference and Exhibit

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Analysis of a Low-Angle Annular Expander Nozzle

Schomberg

Olsen

Doig

2015

Shock and Vibration

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An experimental and numerical analysis of a low-angle annular expander nozzle is presented to observe the variance in shock structure within the flow field. A RANS-based axisymmetric numerical model was used to evaluate flow characteristics and the model validated using experimental pressure readings and schlieren images. Results were compared with an equivalent converging-diverging nozzle to determine the capability of the wake region in varying the effective area of a low-angle design. Comparison of schlieren images confirmed that shock closure occurred in the expander nozzle, prohibiting the wake region from affecting the area ratio. The findings show that a low angle of deflection is inherently unable to influence the effective area of an annular supersonic nozzle design.

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Cycles for Earth-to-Orbit Propulsion

Manski¹,

Goertz²,

Sa-oslash³

et al. 1998

Journal of Propulsion and Power

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The reduction of Earth-to-orbit launch costs in conjunction with an increase in launcher reliability and operational ef ciency are the key demands on future space transportation systems. Results of various system analyses indicate that these demands can be met with future single-stage-to-orbit (SSTO) vehicles using advanced technologies for both structure and propulsion systems. This paper will provide a classi cation and description of all turbopump feed liquid rocket engine cycles, followed by a combined vehicle/propulsion analysis of the design parameters for the propulsion systems and their associated thermodynamic cycles for the launch of future SSTO vehicles. Existing and projected rocket engine cycles capable of SSTO missions will be presented.

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Dual-expander engine flowfield simulations

Cited by 5 publications

References 1 publication

A critical assessment of dual-bell nozzles

A critical assessment of dual-bell nozzles

Analysis of a Low-Angle Annular Expander Nozzle

Cycles for Earth-to-Orbit Propulsion

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