Modeling Boundary Layer Ingestion Using a Coupled Aeropropulsive Analysis

Gray, Justin S.; Mader, Charles A.; Kenway, Gaetan K.; Martins, Joaquim R. R. A.

doi:10.2514/1.c034601

Cited by 81 publications

(41 citation statements)

References 36 publications

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“…Drag and thrust were calculated as net forces integrated over aircraft and propulsion system surfaces, respectively. The overall net force in axial direction was determined as the sum of the integrated pressure and viscous forces over all body surfaces and the pressure and momentum flux contributions on the fan face and fan exit [65][66][67][68]. In a similar manner, Ordaz et al carried out an adjoint-based numerical design and optimization of BLI concepts (NASA STARC-ABL and MTA450-business jet with aft fan) with the objective of minimized flow distortion at the propulsor [69,70].…”

Section: Integral Momentum Methodsmentioning

confidence: 99%

Performance bookkeeping for aircraft configurations with fuselage wake-filling propulsion integration

et al. 2019

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The aim of this research is the identification of a unified bookkeeping and evaluation scheme for the integrated performance analysis of a boundary layer ingesting (BLI) concept in the conceptual design phase. A thorough review and classification of existing performance bookkeeping schemes suits as a basis for the derivation of a bookkeeping scheme suitable for the initial sizing as well as detailed design analysis during the conceptual phase of a BLI concept. Figures of merit for the concept performance assessment are evaluated with regard to the requirements of aircraft multidisciplinary conceptual design. Based on the survey, the most practical integral momentum conservation approach is deduced and its application to integrated conceptual sizing and a subsequent design analysis is evaluated. The proposed scheme is universally applicable to coupled airframe-propulsion aircraft concepts, compatible with standard aircraft and propulsion system sizing tools and, under certain assumptions, deployable for low-and high-fidelity evaluation methods. Finally, several figures of merit are selected to cover a range of design aspects in the BLI evaluation.

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Section: Integral Momentum Methodsmentioning

confidence: 99%

Performance bookkeeping for aircraft configurations with fuselage wake-filling propulsion integration

et al. 2019

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“…The given sensitivities may be applied directly to propagate a given variation (here ±25% as an example) in the incoming momentum deficit (e.g., due to the rather high uncertainty in quantifying this using flat plate theory), which, by using Equations (23)-(25) would translate into an SFC-variation for the four different cases as given in Table 5: This again may be translated into a change in block fuel ∆BF using the given exchange rates from Table 4. Once more detailed information regarding the incoming momentum deficit is available (e.g., from detailed CFD studies as carried out in References [29,40]), the given sensitivities may be used to more reliably quantify the overall BF savings potential at the system level.…”

Section: Inlet Momentum Deficit Sensitivitymentioning

confidence: 99%

“…This again may be translated into a change in block fuel ΔBF using the given exchange rates from Table 4. Once more detailed information regarding the incoming momentum deficit is available (e.g., from detailed CFD studies as carried out in References [29,40]), the given sensitivities may be used to more reliably quantify the overall BF savings potential at the system level.…”

Section: Block-fuel Estimation Of Selected Configurationsmentioning

confidence: 99%

Assessment of a Turbo-Electric Aircraft Configuration with Aft-Propulsion Using Boundary Layer Ingestion

et al. 2019

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In this paper, a turbo-electric propulsion system was analyzed, and its performance was assessed. The aircraft considered here was a single-aisle, medium-range configuration targeting a capacity of 150 Pax. The propulsion concept comprised two boosted geared turbofan engines mounted under-wing. Those main engines were supported by an electrically driven aft-propulsor contributing to the thrust generation and by taking advantage of ingesting the boundary layer of the fuselage for potentially higher levels of propulsive efficiency and allowing for the improved operation of the main engines. The performance assessment as carried out in the context of this paper involved different levels: Firstly, based on the reference aircraft and the detailed description of its major components, the engine performance model for both main engines, as well as for the electrically driven aft-propulsor was set up. The methodology, as introduced, has already been applied in the context of hybrid-electric propulsion and allowed for the aforementioned aircraft sizing, as well as the subsequent gas turbine multi-point synthesis (simulation). A geared turbofan architecture with 2035 technology assumptions was considered for the main engine configuration. The present trade study focused on the design and performance analysis of the aft-propulsor and how it affected the performance of the main engines, due to the electric power generation. In order to allow for a more accurate description of the performance of this particular module, the enhanced streamline curvature method with an underlying and pre-optimized profile database was used to design a propulsor tailored to meet the requirements of the aft propulsor as derived from the cycle synthesis and overall aircraft specification; existing design expertise for novel and highly integrated propulsors could be taken advantage of herein. The resulting performance characteristics from the streamline curvature method were then fed back to the engine performance model in a closely coupled approach in order to have a more accurate description of the module behavior. This direct coupling allowed for enhanced sensitivity studies, monitoring different top-level parameters, such as the thrust/power split between the main engines and the aft propulsor. As a result, different propulsor specifications and fan designs with optimal performance characteristics were achieved, which in return affected the performance of all subsystems considered.

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“…OpenMDAO was developed at NASA Glenn and uses the modular analysis and unified derivatives theory to allow for modular construction and execution of complicated models [20]. OpenMDAO has been used to optimize a variety of problems, including wind turbines [21,22], boundary layer ingestion aircraft [23,24], thermodynamic engine cycles [25,26], and coupled thermal-mission problems [6,27].…”

Section: Tools and Physics Used In This Workmentioning

confidence: 99%

How Certain Physical Considerations Impact Aerostructural Wing Optimization

Jasa

Chauhan

Gray

et al. 2019

AIAA Aviation 2019 Forum

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Wing design optimization has been studied extensively and is of continued interest as optimization tools are developed and become more accessible. In each of these studies, certain assumptions and simplifications are made to make the design problem tractable. However, it is difficult to find systematic studies in which several considerations are added or removed one at a time to study how much impact they have. In this work, we examine how certain physical considerations (viscous drag, wave drag, thrust loads, and inertial relief from structural, fuel, and engine masses), impact the aerostructural optimization results for three distinct aircraft wings. The goal is to help develop a rough idea of how important these physical considerations are. We do this using gradient-based optimization and a multidisciplinary design optimization framework, OpenMDAO. We use the open-source tool OpenAeroStruct that couples a vortex lattice method to a finite element method. We establish a baseline aerostructural design optimization problem then perform a series of optimizations, each with one physical consideration removed from the baseline case. We find that depending on the size of the aircraft and flight conditions, the importance of some of these physical considerations varies considerably whereas the importance of others do not. Specifically, the optimal designs change radically without proper viscous and wave drag considerations and smaller aircraft with more distributed propulsion are more affected by the inclusion of engine loads.

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Modeling Boundary Layer Ingestion Using a Coupled Aeropropulsive Analysis

Cited by 81 publications

References 36 publications

Performance bookkeeping for aircraft configurations with fuselage wake-filling propulsion integration

Performance bookkeeping for aircraft configurations with fuselage wake-filling propulsion integration

Assessment of a Turbo-Electric Aircraft Configuration with Aft-Propulsion Using Boundary Layer Ingestion

How Certain Physical Considerations Impact Aerostructural Wing Optimization

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