Assessment of a Boundary Layer Ingesting Turboelectric Aircraft Configuration using Signomial Programming

Hall, David K.; Dowdle, Aidan P.; Gonzalez, J.; Trollinger, Lauren; Thalheimer, W.

doi:10.2514/6.2018-3973

Cited by 16 publications

(18 citation statements)

References 7 publications

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“…Hall et al [26,27] applied the power balance method to a ducted BLI configuration in which the whole propulsion system is simplified by a single propulsor installed at the trailing edge of the fuselage. Their approach is based on a formulation of the power balance method applied to a control volume in the manner of Fig.…”

Section: Mechanical Flow Power Power-based Propulsive Efficiency Andmentioning

confidence: 99%

“…A comparative evaluation of the BLI system-level benefit (comparison of BLI to reference non-BLI configuration) from a propulsion system standpoint is convenient for the application of the power saving coefficient in its fundamental formulation: (27) F bare,axial,net =̇I out,CV5 −̇I in,CV1 −̇I in,CV3 + F p,out,CV5…”

Section: Applied Figures Of Meritmentioning

confidence: 99%

“…When applied to the right-hand side of Eq. (32), the linear momentum equation is derived: Incompressible propulsive efficiency, Smith [47] General propulsive efficiency, Plas et al [75] Thrust benefit, Kim and Felder [15] Net propulsive force, Goldberg et al [61,62] (Power balance) PSC, Blumenthal et al [23,24] Propulsive mechanical flow power, Drela [17] (Power balance) Propulsive efficiency, Hall et al [26,27] Exergy recovery coefficient, Arntz [18] Degree of universality (scale: 0 or 1) Rating Covered flow properties Compressibility 0.00 0.00 1.00 For steady flow, the first term on the right-hand side of Eq. (34) (i.e., the change of momentum inside the control volume over time) becomes 0.…”

Section: Momentum Conservation Applicationmentioning

confidence: 99%

“…Instead of the traditional force-based calculation of drag and thrust, the benefit of BLI is measured by an integrated propulsion power [17]. Drela's method is widely applied in BLI concept studies featuring a trailing edge propulsor in the MIT and NASA D8 projects, at the Delft University of Technology and sparsely in similar projects [23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38][39][40][41].…”

Section: Introductionmentioning

confidence: 99%

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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: Mechanical Flow Power Power-based Propulsive Efficiency Andmentioning

confidence: 99%

Section: Applied Figures Of Meritmentioning

confidence: 99%

Section: Momentum Conservation Applicationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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

et al. 2019

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“…The method relies on the power balance approach developed by Drela (7) and subsequently applied on a hybrid-wing-body by Sato (8) , and on the D8 aircraft by Hall et al (9) and Uranga et al (10) . In this paper, the method has been extended in order to assess the BLI benefit of propulsive fuselage tube-and-wing aircraft, similar to the work of Hall et al (5) . The analytical method also covers the integration of the fuselage fan propulsion system at aircraft level in order to explore the design space in terms of fuel burn.…”

Section: Introductionmentioning

confidence: 99%

Turbo-electric propulsive fuselage aircraft BLI benefits: A design space exploration using an analytical method

2020

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Turbo-electric propulsive fuselage aircraft featuring Boundary-Layer Ingestion (BLI) are considered promising candidates to achieve the emissions reduction targets set for aviation. This paper presents an analytical method capable of estimating the BLI benefit at aircraft level, enabling a quick exploration of the propulsive fuselage design space. The design space exploration showed that the assumptions regarding the underwing turbofans and BLI fan mass estimation can have an important impact on the final fuel burn estimation. The same applies to the total efficiency assumed for the electric transmission, the range of the aircraft mission, and the propulsive efficiency of the engines used as benchmark. The regional jet and short- to medium-range aircraft classes seem to be the most promising as the ingested drag and power saving are among the largest, with long-range aircraft being just behind. The future introduction of advanced technologies, which target the reduction of vortex and wave dissipation at aircraft level, could increase the potential benefit of propulsive fuselage BLI. On the other hand, the potential benefit would be decreased if more efficient and lighter ultra high bypass ratio engines were used as benchmark.

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Newton Polytopes and Relative Entropy Optimization

2021

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Newton polytopes play a prominent role in the study of sparse polynomial systems, where they help formalize the idea that the root structure underlying sparse polynomials of possibly high degree ought to still be "simple." In this paper we consider sparse polynomial optimization problems, and we seek a deeper understanding of the role played by Newton polytopes in this context. Our investigation proceeds by reparametrizing polynomials as signomialswhich are linear combinations of exponentials of linear functions in the decision variable -and studying the resulting signomial optimization problems. Signomial programs represent an interesting (and generally intractable) class of problems in their own right. We build on recent efforts that provide tractable relative entropy convex relaxations to obtain bounds on signomial programs. We describe several new structural results regarding these relaxations as well as a range of conditions under which they solve signomial programs exactly. The facial structure of the associated Newton polytopes plays a prominent role in our analysis. Our results have consequences in two directions, thus highlighting the utility of the signomial perspective. In one direction, signomials have no notion of "degree"; therefore, techniques developed for signomial programs depend only on the particular terms that appear in a signomial. When specialized to the context of polynomials, we obtain analysis and computational tools that only depend on the particular monomials that constitute a sparse polynomial. In the other direction, signomials represent a natural generalization of polynomials for which Newton polytopes continue to yield valuable insights. In particular, a number of invariance properties of Newton polytopes in the context of optimization are only revealed by adopting the viewpoint of signomials.

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Assessment of a Boundary Layer Ingesting Turboelectric Aircraft Configuration using Signomial Programming

Cited by 16 publications

References 7 publications

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

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

Turbo-electric propulsive fuselage aircraft BLI benefits: A design space exploration using an analytical method

Newton Polytopes and Relative Entropy Optimization

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