Multidisciplinary approach to linear aerospike nozzle optimization

Korte, John J.; Salas, A. O.; Dunn, H. J.; Alexandrov, Natalia; Follett, W. W.; Orient, George Edgar; Hadid, A. H.

doi:10.2514/6.1997-3374

Cited by 20 publications

(7 citation statements)

References 6 publications

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“…Therefore, an aerospike nozzle yields higher thrust performance and specific impulse of various altitudes, resulting in higher thrust performance compared with that by conventional bell-shaped nozzles. [1][2][3] One of the other advantages of an aerospike nozzle is that differential throttling 4,5 is possible by "clustering" the cell rocket nozzles without using many small thrusters to control vehicle attitudes. Jet exhaust flow of clustered linear aerospike emits from each parallel cell nozzle.…”

Section: Introductionmentioning

confidence: 99%

Three dimensional numerical investigation of the clustered linear aerospike nozzle’s flow affected by changing the distance between neighboring cell nozzles

Miyazawa

Matsuo

Takahashi

et al. 2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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Aerodynamic performance of the simplified test models of infinite consequence clustered linear aerospike nozzles was numerically investigated and results were compared with those of an experimental study. The model of numerical target is focused on predicting the ramp pressure distribution and the effect of interval of the neighboring clustered cell nozzles, where jet exhaust flow emits 3.5 in Mach number. Its thrust performances were examined in terms of two types of the cell nozzle interval, 4 and 17 mm, whose model is named half4c and half3c respectively. Clustered cell nozzles connect with a straight ramp, and another end of the straight ramp connects with a 12-degree-inclined slope ramp. The ramp consists of a pair of these ramps. External main flow in Mach 2.0 impinges on the N 2 cell nozzle jets and ramp surface. On the ramp surface, pressure distribution illustrated clear cell pattern resulting from three-dimensional bumpy oblique shock wave generated above slope ramp. NDP (Normalized Difference Pressure) at ramp of CFD was compared with that of experiment. It showed quantitative agreement within 10% difference. NDP distribution at jet center of span wise cross-section showed opposite phase differences from that at base center. Flow features from streamline showed the presence of vertical vortex and the deflection of main flow and jet flow. Streamline not only showed how to mix between these flows but also suggested that oblique shock wave generated at front half of a slope ramp was bumpy as shown in the great deflection of stream. At half4c model, main flow did not sink to near the ramp wall except in the case of over-expansion, while at half3c model a part of main flow was mixed with jet flow at jet center only in the case of over-expansion. Thus flow features could be classified by whether expansion form is over-expansion in both cell nozzle intervals. The ramp pressure distribution reflects to pressure thrust. Consider the situation that straight ramp angle against the virtual airframe axis plane can be changed. At this time, the airframe angle of making thrust maximum tended to decrease with increase in NPR and with becoming shorter in cell nozzle interval. NomenclatureA w = ramp wall surface area, mm 2 A r = cell nozzle cross-section area, mm 2 V r = jet exhaust velocity, m/s M a = freestream (external main flow) Mach number M r = cell nozzle jet exhaust Mach number NDP = Normalized difference pressure defined as (P-P b )/P 0r NPR = Nozzle Pressure Ratio defined as P 0r /P b P a = freestream (external main flow) static pressure, kPa P b = static pressure in the test chamber, kPa P r = jet Mach number at cell nozzle exit, kPa P w = ramp pressure, kPa P 0a = total pressure of freestream (main flow), kPa P 0r = chamber pressure of cell nozzle jet flow, kPa x = coordinate in stream wise direction, mm y = coordinate in transverse direction, mm z = coordinate in span wise direction, mm θ = airframe angle, which is straight ramp angle against the virtual airframe axis plane, deg. θ max = optimum airframe a...

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Section: Introductionmentioning

confidence: 99%

Three dimensional numerical investigation of the clustered linear aerospike nozzle’s flow affected by changing the distance between neighboring cell nozzles

Miyazawa

Matsuo

Takahashi

et al. 2013

49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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show abstract

“…The latest aerospike nozzle design performed in the United States is based on the multidisciplinary optimization method 1011 . Both aerodynamic and structural analyses were coupled and the significant improvements were demonstrated by using an multidisciplinary approach in comparison with the single discipline design strategy 10 . The engine performance was also optimized considering the vehicle's trajectory".…”

Section: Introductionmentioning

confidence: 99%

Flow field analysis of the base region of axisymmetric aerospike nozzles

Ito¹,

Fujii

2001

39th Aerospace Sciences Meeting and Exhibit

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Characteristics of aerospike nozzle flow fields are discussed based on the results of numerical simulations. The computations are carried out for the 20% truncated nozzle with the external flow introduced. Two high-pressure regions which are created by the shear layer impingement of the nozzle exhaust flow and the envelope shock wave impingement appear on the nozzle axis. The flow stagnates either of the higher pressure region of these two and the strong reverse flow toward the base surface occurs. The base pressure is influenced by the ambient pressure when the pressure ratio is low as the flow stagnates at the high-pressure region created by the impingement of the envelope shock. On the other hand, the base pressure becomes independent from the ambient pressure when the pressure ratio is high as the flow changes its stagnation point to where the shear layer of the nozzle flow impinges on the nozzle axis. The analysis shows that these flow mechanisms change the characteristics of the base pressure dramatically between the low-pressure and high-pressure ratio regions.

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“…In 1995 the MDO Branch at NASA Langley and Rocketdyne, Inc. started a joint development of MDO methods, focused on the design of the nozzle of an aerospike engine, 27 an engine concept used for the X-33. Fig.…”

Section: Aerospike Nozzlementioning

confidence: 99%

“…In the meantime, stopgap measures must be employed. In the aerospike nozzle application, 27 MATLAB™ scripts were used in a novel way to parameterize a conventional NASTRAN™ model of the structure. In the HSCT 4 application, the CAD representation was exported to a NURBS (nonuniform rational B-spline) representation and shape deformation methods 47 were applied to yield the parameterization illustrated above in Fig.…”

Section: Parametric Geometric Modelingmentioning

confidence: 99%

Multidisciplinary design optimization techniques - Implications and opportunities for fluid dynamics research

Zang

Green

1999

30th Fluid Dynamics Conference

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A challenge for the fluid dynamics community is to adapt to and exploit the trend towards greater multidisciplinary focus in research and technology. The past decade has witnessed substantial growth in the research field of Multidisciplinary Design Optimization (MDO). MDO is a methodology for the design of complex engineering systems and subsystems that coherently exploits the synergism of mutually interacting phenomena. As evidenced by the papers, which appear in the biannual AIAA/USAF/NASA/ISSMO Symposia on Multidisciplinary Analysis and Optimization, the MDO technical community focuses on vehicle and system design issues. This paper provides an overview of the MDO technology field from a fluid dynamics perspective, giving emphasis to suggestions of specific applications of recent MDO technologies that can enhance fluid dynamics research itself across the spectrum, from basic flow physics to full configuration aerodynamics.

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Multidisciplinary approach to linear aerospike nozzle optimization

Cited by 20 publications

References 6 publications

Three dimensional numerical investigation of the clustered linear aerospike nozzle’s flow affected by changing the distance between neighboring cell nozzles

Three dimensional numerical investigation of the clustered linear aerospike nozzle’s flow affected by changing the distance between neighboring cell nozzles

Flow field analysis of the base region of axisymmetric aerospike nozzles

Multidisciplinary design optimization techniques - Implications and opportunities for fluid dynamics research

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