Experimental investigation of the evacuation effect in expansion deflection nozzles

Taylor, Neil; Hempsell, CM; Macfarlane, J. J.; Osborne, Robin; Varvill, Richard; Bond, A.; Feast, Simon

doi:10.1016/j.actaastro.2009.07.016

Cited by 18 publications

(8 citation statements)

References 6 publications

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“…A larger wake region would theoretically experience a lower area-weighted evacuation effect caused by the interacting shear layers, a factor previously credited with reducing thrust efficiency of the ED nozzle through a reduction in wake pressure. 19 Trend variations in the pintle contour geometry were relatively consistent, indicating that pintle angles should be within the upper range of the values tested, whereas curve radii should be minimized where possible. The increase in thrust coefficient as a result of throat angle was effectively constant at a value of 0.075 and showed that the angle of the nozzle throat should be equal to the maximum expansion angle in all cases.…”

Section: Figure 10 Main Effects Trend Of Geometric Parametersmentioning

confidence: 84%

Geometric Analysis of the Linear Expansion-Deflection Nozzle at Highly Overexpanded Flow Conditions

Schomberg

Doig²,

Olsen³

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

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The effect of nozzle geometry on the thrust efficiency of the linear expansion-deflection (ED) nozzle concept has been investigated at highly overexpanded flow conditions. A new design method for generation of the ED nozzle contour is introduced and a factorial-based approach used to determine the effect of nozzle geometry on thrust coefficient. An area ratio of 17.6 was selected to represent a core stage nozzle and eight geometric parameters compared across sixteen separate configurations. Thrust coefficient was determined numerically from a time-dependent model using dry air as the working fluid. The numerical model was verified with respect to viscous effects and dimensional grid parameters, and then validated against experimental results to quantify sources of numerical error. Results were obtained for pressure ratios ranging from 5-50 to replicate highly overexpanded conditions where flow separation would occur in an equivalent conventional nozzle. Thrust coefficient in all ED nozzle configurations relative to the conventional nozzle ranged between 105-190% at low pressures and 90-120% at high pressures. The conclusions from the factorial analysis of ED nozzle contour geometry suggested that low curve radii and high inflection angles would further improve thrust coefficient for the flow conditions tested. The results show that an improvement in thrust relative to a conventional design can be expected at highly overexpanded flow conditions through the use of an ED nozzle configuration. NomenclatureA = Area (m 2 ) R = Specific gas constant (kJkg -1 K -1 ) C = Contraction ratio r = Radius (m) C F = Thrust coefficient v = Velocity (ms -1 ) C F,% = Thrust efficiency x = Longitudinal direction (m) G t = Throat gap (m) y = Lateral direction (m) ̇ = Mass flow rate (kgs -1 ) γ = Ratio of specific heats P = Static pressure (Pa) θ = Wall angle (°) Subscripts 0 = Stagnation conditions e = Pintle contour point e a = Pintle contour point a i = Arbitrary contour point i amb = Local ambient conditions j = Arbitrary contour point j b = Pintle contour point b m = Nozzle contour point m c = Pintle contour point c n = Nozzle contour point n d = Pintle contour point d t = Throat region 1 PhD Candidate, kyll.schomberg@unsw.edu.au, Student Member AIAA.

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Section: Figure 10 Main Effects Trend Of Geometric Parametersmentioning

confidence: 84%

Geometric Analysis of the Linear Expansion-Deflection Nozzle at Highly Overexpanded Flow Conditions

Schomberg

Doig²,

Olsen³

et al. 2014

50th AIAA/ASME/SAE/ASEE Joint Propulsion Conference

View full text Add to dashboard Cite

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“…The hypotheses from Migdal, 8 Chutkey and Vasudevan, 9 Davidenki et al., 10 and Taylor et al. 11 does not really reflect the physical flow behavior when M E and T 0 are high, exceeding respectively 2.00 and 500 K. The studied of 2D nozzle is no longer an important practice compared to the axisymmetric geometry.…”

Section: Introductionmentioning

confidence: 98%

“…For aerospace application, an experimental study of the supersonic flow in 2D expansion deflexion nozzle (EDN) was carried out in order to obtain its experimental performances, which was the objective of Taylor et al. 11…”

Section: Introductionmentioning

confidence: 99%

“…It can reach 80% of the propulsive chamber. 1,2 For the purpose of performance control, the study by Migdal, 8 Chutkey and Vasudevan, 9 Davidenki et al, 10 and Taylor et al 11 was with regard to a numerical flow simulation in 2D chosen nozzle's shape for the calorically and thermally perfect gas (PG). This nozzle does not allow for a complete expansion.…”

Section: Introductionmentioning

confidence: 99%

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Performance improvement of supersonic nozzles design using a high-temperature model

Hamaidia

Zebbiche

Sellam

et al. 2019

Proceedings of the Institution of Mechanical Engineers, Part G:

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The aim of this paper is to discuss the development of new contours of axisymmetric supersonic nozzles giving a uniform and parallel flow at the exit section, to improve the aerodynamic performances compared to the minimum length nozzle, by increasing the exit Mach number and the thrust coefficient, and by reduction of the nozzle's mass, while holding the same throat section between the two nozzles. The new nozzle is named the best performance nozzle. Its form contains a cylindrical central body and an external wall for the flow redress. The study is done at high temperature, lower than the dissociation threshold of the molecules. The variation of the specific heats with the temperature is considered. The design is made by the method of characteristics. The predictor-corrector algorithm is used to make the numerical resolution of the obtained nonlinear algebraic equations. The validation of results is made by the convergence of the numerical critical sections ratio with that given by the theory. The comparison of the results is made with the minimum length nozzle since it is currently used in the aerospace propulsion. The design depends on M E, T0, y body, y*, and the mesh generation. The application is done with air. A computational fluid dynamics verification for the under nozzle expressed regime has shown that a flow separation with the wall is observed because of the side-loads, which are reduced for this new nozzle compared to the minimum length nozzle.

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“…The substantial cost of transporting payload into orbit has created the demand for a reusable, single stage launch system. It has been estimated that a reusable single stage launch system has the potential to reduce the cost per kilogram to orbit by an order of magnitude [1]. Propulsion systems fitted with conventional convergent-divergent nozzles which operate from sea level to the vacuum conditions (Space Shuttle Main Engine, Vulcain, etc.)…”

Section: Introductionmentioning

confidence: 99%

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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Experimental investigation of the evacuation effect in expansion deflection nozzles

Cited by 18 publications

References 6 publications

Geometric Analysis of the Linear Expansion-Deflection Nozzle at Highly Overexpanded Flow Conditions

Geometric Analysis of the Linear Expansion-Deflection Nozzle at Highly Overexpanded Flow Conditions

Performance improvement of supersonic nozzles design using a high-temperature model

Analysis of a Low-Angle Annular Expander Nozzle

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