CFD Based Study of Unconventional Aeroengine Exhaust Systems

Coates, Tim; Page, Gary J.

doi:10.2514/6.2012-2775

Cited by 10 publications

(3 citation statements)

References 22 publications

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“…Components with S-shaped features are widely used in aeroengines, for example, inlet particle separator, S-shaped diffuser, compressor transition duct, intermediate turbine duct, and S-shaped nozzle. [1][2][3][4][5] Large curvature characteristics are located in such S-shaped ducts, and complex internal flow characteristics would be induced due to the existence of curvature, and then the performances of such components can be influenced. To design high-performance components with large curvatures, it is necessary to explore the mechanism of compressible flow features in such curved ducts.…”

Section: Introductionmentioning

confidence: 99%

Influences of key parameters on flow features in the curved ducts with equal area

Sun

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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Curved ducts are widely used in aircraft engines to improve some capability of aero-engines. Complex internal flow characteristics would be induced by the curvature in such components. In this study, the influence of parameters, including the arc angle α, the curvature radius R i, and the height H, on the local accelerating and transonic flow in the curved ducts with equal area were studied numerically and theoretically under different nozzle pressure ratios (NPRs). The range of the Re number based on the height of the duct and the velocity at the inlet was [Formula: see text] ∼ [Formula: see text]. The shear stress transport κ-ω turbulent model was proved by the test data to suitably simulate the flow field in curved ducts because it could accurately predict the flow separations under adverse pressure gradients. The uncertainty of the pressure scan value to obtain the test data was ±0.05%. Numerical results showed that the effect of α on the flow characteristics of the curved ducts is little. The maximum Ma number in the curved section reduces with the increase of R i, and that grows with the increase of H. The range of the maximum Ma number was 1.20∼1.80. The critical NPRs, which decided the special flow features, were found in the curved ducts. The critical NPR rises with the increase of R i; however, the effect of H on the critical NPR is irregular due to the flow separations located near the lower wall induced by the large adverse pressure gradient. The theoretical results based on the small perturbation theory of transonic flow in the polar coordinate system proved that the distribution of sonic line was just dependent on the inner diameter R1, the outer diameter R2, and the arc angle θmax of the curved section. The critical mass flow and the critical NPR2 are only related to R1 and R2.

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Section: Introductionmentioning

confidence: 99%

Influences of key parameters on flow features in the curved ducts with equal area

Sun

2021

Proceedings of the Institution of Mechanical Engineers, Part C:

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“…14 These geometric design parameters definitely have important impacts on the characteristics of flow, IR, and RCS of the serpentine nozzle. Coates and Page 15 conducted the study of unconventional aero-engine exhaust systems, where a contracting S-bend duct was combined with a divergent nozzle. Three different upstream S-duct curvatures were considered, and results showed that the increasing upstream duct curvature reduced the potential core length, but increased losses in the upstream duct.…”

Section: Introductionmentioning

confidence: 99%

Internal flow and external jet characteristics of double serpentine nozzle with different aspect ratio

Xiaolin

Wang

et al. 2017

Proceedings of the Institution of Mechanical Engineers, Part G:

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In order to increase the survivability of the fighter aircraft, the serpentine nozzle has been applied in series of stealth bombers and unmanned aerial vehicles due to its excellent potentiality of evidently suppressing the infrared radiation signatures and radar cross section emitted by engine exhausts. Among the geometric parameters of the serpentine nozzle, the aspect ratio (AR) at the nozzle exit is one of the most critical parameters for the nozzle design as the infrared suppression effect could be greatly enhanced with the increment of AR by strengthening the mixing between the exhaust plume and atmosphere; the aim of this paper is to study the influence of the AR on the flow characteristics of the double serpentine nozzle. The flow features of six double serpentine convergent nozzles, i.e. AR = 3, 5, 7, 9, 11, 15 respectively, were numerically simulated with the shear stress transport κ–ω turbulent model adopted, which had been validated by the experimental data. The characteristics of internal flow and external jet, and the aerodynamic performances of these six nozzles were compared. Results show that the Ma contours at the symmetric plane are different due to the distinct flow accelerations caused by the change of the curvature and the duct height for diverse AR, and the surface pressure and the shock wave features are different correspondingly. The lateral divergence and the lateral convergence characteristics of the nozzle configuration lead to opposite lateral flow under diverse AR, and the change of lateral width induced different lateral pressure gradient, then lead to various lateral vortex distributions. The length of potential core is the contribution of the comprehensive effects of geometry parameters, and it is decreased with the increase of AR due to the dominated effect of the increased mixing area; however, the declining rate is slowed down. The AR of 5 should be chosen for the best aerodynamic performance of the double serpentine nozzle under the qualifications to completely shield the high-temperature turbine.

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“…1 The simulations were run using four different turbulence models. The Rolls Royce Hydra code (version 6.2.16) was used for the Spalart-Allmaras, k-and k-ω SST turbulence models whilst the ANSYS Fluent code was used for the Reynolds-Stress second order turbulence model.…”

Section: Iiic Comparison Of Cfd Methods For An S-bend Duct Of 13d mentioning

confidence: 99%

LES of High Speed Jet Flow From Convergent-Divergent Rectangular S-bend Ducts Using Synthetic Inlet Conditions

Coates

Page

2013

21st AIAA Computational Fluid Dynamics Conference

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CFD Based Study of Unconventional Aeroengine Exhaust Systems

Cited by 10 publications

References 22 publications

Influences of key parameters on flow features in the curved ducts with equal area

Influences of key parameters on flow features in the curved ducts with equal area

Internal flow and external jet characteristics of double serpentine nozzle with different aspect ratio

LES of High Speed Jet Flow From Convergent-Divergent Rectangular S-bend Ducts Using Synthetic Inlet Conditions

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