Selection of a Propulsor for a Submersible System

Gearhart, W. S.; Henderson, R. E.

doi:10.2514/3.59270

Cited by 21 publications

(14 citation statements)

References 4 publications

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“…Boundary layer ingestion (BLI) for aircraft applications was first proposed by Apollo Smith and Howard Roberts in a 1947 paper that studied the use of jet intakes embedded in the boundary layer as a means to maintain laminar flow and reduce aircraft drag [1]. Aircraft applications for BLI were not examined in further detail initially, but the idea was studied under the term "wake ingestion" for marine applications in the 1960's [2,3]. In 1993 interest in BLI for aircraft applications was renewed when Leyroy Smith published novel work using a boundary layer analysis, combined with basic propulsion modeling to show the potential for significant fuel burn reduction [4].…”

Section: Introductionmentioning

confidence: 99%

Aero-propulsive Design Optimization of a Turboelectric Boundary Layer Ingestion Propulsion System

Gray

Kenway²,

Mader

et al. 2018

2018 Aviation Technology, Integration, and Operations Conference

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Boundary layer ingestion is a coupled aeropropulsive technology that offers the potential for significant improvements to aircraft vehicle performance. NASA's STARC-ABL aircraft configuration is particularly interesting because it leverages boundary layer ingestion with a mostly traditional fuselage. However the design of of STARC-ABL's propulsion systems poses a challenge because the tightly coupled aeropropulsive system is not well handled by traditional uncoupled design methods. To address this we developed a fully coupled aeropropulsive design optimization of the boundary layer ingestion propulsor the STARC-ABL configuration. The integrated model was assembled in the OpenMDAO framework using a three-dimensional RANS CFD aerodynamics model and a one-dimensional thermodynamic propulsion model. The fan for the boundary layer ingestion propulsor was modeled in two parts: a body-force actuator zone is included in the aerodynamics model to produce the thrust and the thermodynamic efficiency of the fan is computed in the propulsion model. The optimization was performed using a gradient based algorithm with the necessary derivatives computed analytically using an adjoint method. The geometry for the aerodynamics model allowed for fine-shape changes of the aft-fuselage, the nacelle walls, and nozzle plug, and for variation of the nacelle diameter. The results show that variations in required thrust also result in different diameters for the optimized propulsor geometries, with fan pressure ratios staying as low as allowed.

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Section: Introductionmentioning

confidence: 99%

Aero-propulsive Design Optimization of a Turboelectric Boundary Layer Ingestion Propulsion System

Gray

Kenway²,

Mader

et al. 2018

2018 Aviation Technology, Integration, and Operations Conference

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“…Although boundary layer ingestion (BLI), or wake ingestion, has been well studied for marine applications since the 1960s [1,2,3] it has not yet seen wide-spread adoption in aircraft applications. However, recent studies have considered several new BLI-based aircraft configurations that could offer a reduction in aircraft fuel burn between 5% and 12% [4,5,6].…”

Section: Introductionmentioning

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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“…Here the sum of skin friction and pressure drag is the lowest in relation to volume. These results have been determined in wind tunnels and water channels at Reynolds numbers in the vicinity of 10 7 . As the Reynolds number increases, the skin friction will decrease but the pressure drag will increase according to the turbulent separation criterion of Goldschmied.…”

Section: Fineness-ratio Effectmentioning

confidence: 99%

“…For instance, for a 5:1 streamlined body and stern propulsion, McLemore 2 reports a C P * = 0.020 at R L = 1.75 X 10 7 . This results from a C D = 0.021 and an apparent propulsive efficiency of 105%, on the basis of enclosed volume.…”

Section: Comparison With Conventional Bodiesmentioning

confidence: 99%

Integrated Hull Design, Boundary-layer Control and Propulsion of Submerged Bodies: Wind-Tunnel Verification

Goldschmied¹

1982

18th Joint Propulsion Conference

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Power requirements of large submerged bodies at high Reynolds numbers are optimized by the hydrodynamic synthesis of body design, boundary-layer control, and propulsion. Conventional rigid skin, all turbulent boundary layers, and a single suction slot are accepted as realistic engineering constraints. A 3:1 body has been designed and has been tested in a wind tunnel at a Reynolds number of 10 7 ; the wake drag has been found to be CDW = 0.002, and the equivalent suction drag CDS = 0.0142 yielding a total equivalent drag CD = 0.0162 (based on volume). This can be compared to CD = 0.0235 for the best conventional streamlined body (Akron airship model). A total engine power coefficient has also been determined, Cp* = 0.01585, while a conventional streamlined vehicle with stern wake propeller has a Cp* = 0.0215, thereby showing a net gain of 26%. There is a possible tradeoff between suction and propulsion powers allowing the total power coefficient to decrease to CP* = 0.0100 and to reach a 50% power gain.

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Selection of a Propulsor for a Submersible System

Cited by 21 publications

References 4 publications

Aero-propulsive Design Optimization of a Turboelectric Boundary Layer Ingestion Propulsion System

Aero-propulsive Design Optimization of a Turboelectric Boundary Layer Ingestion Propulsion System

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

Integrated Hull Design, Boundary-layer Control and Propulsion of Submerged Bodies: Wind-Tunnel Verification

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