Inlet Trade Study for a Low-Boom Aircraft Demonstrator

Heath, Christopher M.; Slater, John W.; Rallabhandi, Sriram K.

doi:10.2514/1.c034036

Cited by 13 publications

(18 citation statements)

References 14 publications

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“…There has been some recent work developing coupled propulsion-aerodynamic models for supersonic applications. Heath et al [26] manually coupled a RANS analysis to a propulsion model by matching the flow areas and states between the two and using the propulsion model to predict the static pressure for the fan-face boundary condition. This work compared the installed performance and sonic boom for two discrete inlet designs, and the limited number of configurations made manual coupling a reasonable approach.…”

Section: Fully Coupled Modelmentioning

confidence: 99%

Approach to Modeling Boundary Layer Ingestion using a Fully Coupled Propulsion-RANS Model

Gray

Mader

Kenway

et al. 2017

58th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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Airframe-propulsion integration concepts that use boundary layer ingestion have the potential to reduce aircraft fuel burn. One concept that has been recently explored is NASA's Starc-ABL aircraft configuration, which offers the potential for 12% mission fuel burn reduction by using a turbo-electric propulsion system with an aft-mounted electrically driven boundary layer ingestion propulsor. This large potential for improved performance motivates a more detailed study of the boundary layer ingestion propulsor design, but to date, analyses of boundary layer ingestion have used uncoupled methods. These methods account for only aerodynamic effects on the propulsion system or propulsion system effects on the aerodynamics, but not both simultaneously. This work presents a new approach for building fully coupled propulsive-aerodynamic models of boundary layer ingestion propulsion systems. A 1D thermodynamic cycle analysis is coupled to a RANS simulation to model the Starc-ABL aft propulsor at a cruise condition and the effects variation in propulsor design on performance are examined. The results indicates that both propulsion and aerodynamic effects contribute equally toward the overall performance and that the fully coupled model yields substantially different results compared to uncoupled. The most significant finding is that boundary layer ingestion, while offering substantial fuel burn savings, introduces throttle dependent aerodynamics effects that need to be accounted for. This work represents a first step toward the multidisciplinary design optimization of boundary layer ingestion propulsion systems.

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Section: Fully Coupled Modelmentioning

confidence: 99%

Approach to Modeling Boundary Layer Ingestion using a Fully Coupled Propulsion-RANS Model

Gray

Mader

Kenway

et al. 2017

58th AIAA/ASCE/AHS/ASC Structures, Structural Dynamics, and Materials Conference

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“…1. The low-boom airframe was reverse-engineered from [4], with the axisymmetric spike inlet and propulsion flow path down-selected from the trade study in [7]. Modifications to the inlet were made for this study to improve off-design operation and are reported in Section III-A.…”

Section: Problem Definition a Baseline Vehicle Configuration Descriptionmentioning

confidence: 99%

“…The engine core paired with the inlet is representative of a General Electric F404-GE-402 afterburning turbofan, throttled to produce approximately 4500-lbf thrust at cruise with partial afterburner. As a result of engine installation in [7], vehicle sonic boom loudness was moderately compromised across the entire boom carpet. This study uses aerodynamic shape optimization to recover a portion of the sacrificed sonic boom loudness margin lost during engine integration.…”

Section: Problem Definition a Baseline Vehicle Configuration Descriptionmentioning

confidence: 99%

“…The cruise C L target is 0.065, which corresponds to a 21,000-lbf gross take-off weight (GTOW). In [7], the vehicle cruise angle of attack was adjusted to match the target C L . Similarly, the nozzle gross thrust was tailored to balance overall drag forces (vehicle drag plus inlet ram drag) and match the engine mass flow rate consistent with the thermodynamic engine cycle model.…”

Section: Problem Definition a Baseline Vehicle Configuration Descriptionmentioning

confidence: 99%

“…In addition, conceptual design often omits viscous aerodynamic effects which can have a detrimental impact on installed propulsive performance and vehicle sonic boom loudness levels. For example, prior research [5][6][7] has indicated that adding viscous or propulsion effects into a pre-optimized low-boom airframe signature can greatly compromise sonic boom performance.…”

Section: Introductionmentioning

confidence: 99%

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Viscous Aerodynamic Shape Optimization with Installed Propulsion Effects

Heath

Seidel

Rallabhandi

2017

35th AIAA Applied Aerodynamics Conference

Self Cite

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Aerodynamic shape optimization is demonstrated to tailor the under-track pressure signature of a conceptual low-boom supersonic aircraft. Primarily, the optimization matches the near-field pressure disturbances induced by propulsion integration effects to a prescribed low-boom target. For computational efficiency, gradient-based optimization is used and coupled to the discrete adjoint formulation of the Reynolds-averaged Navier Stokes equations. The engine outer nacelle, nozzle, and vertical tail fairing are axi-symmetrically parameterized, while the horizontal tail is shaped using a wing-based parameterization. Overall, 48 design variables are coupled to the geometry and used to deform the outer mold line. During the design process, an inequality drag constraint is enforced to avoid major compromise in aerodynamic performance. Linear elastic mesh morphing is used to deform the volume grid between design iterations. The optimization is performed at Mach 1.6 cruise, assuming standard day altitude conditions at 51,707-ft. To reduce uncertainty, a coupled thermodynamic engine cycle model is employed that captures installed inlet performance effects on engine operation.

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The inlet flow structure of a conceptual open-nose supersonic drone

Saheby

Shen

Hays

et al. 2021

Proceedings of the Institution of Mechanical Engineers, Part G:

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This study describes the aerodynamic efficiency of a forebody–inlet configuration and computational investigation of a drone system, capable of sustainable supersonic cruising at Mach 1.60. Because the whole drone configuration is formed around the induction system and the design is highly interrelated to the flow structure of forebody and inlet efficiency, analysis of this section and understanding its flow pattern is necessary before any progress in design phases. The compression surface is designed analytically using oblique shock patterns, which results in a low drag forebody. To study the concept, two inlet–forebody geometries are considered for Computational Fluid Dynamic simulation using ANSYS Fluent code. The supersonic and subsonic performance, effects of angle of attack, sideslip, and duct geometries on the propulsive efficiency of the concept are studied by solving the three-dimensional Navier–Stokes equations in structured cell domains. Comparing the results with the available data from other sources indicates that the aerodynamic efficiency of the concept is acceptable at supersonic and transonic regimes.

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Inlet Trade Study for a Low-Boom Aircraft Demonstrator

Cited by 13 publications

References 14 publications

Approach to Modeling Boundary Layer Ingestion using a Fully Coupled Propulsion-RANS Model

Approach to Modeling Boundary Layer Ingestion using a Fully Coupled Propulsion-RANS Model

Viscous Aerodynamic Shape Optimization with Installed Propulsion Effects

The inlet flow structure of a conceptual open-nose supersonic drone

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