Exergy-Based Formulation for Aircraft Aeropropulsive Performance Assessment: Theoretical Development

Arntz, Aurélien; Atinault, Olivier; Merlen, Alain

doi:10.2514/1.j053467

Cited by 78 publications

(61 citation statements)

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“…Cancellation of the wake/jet downstream of the configuration allows a reduction in anergy production, which in turn allows for lower exergy supply by the propulsion system. From quantitative aircraft-performance considerations, one can introduce an exergy-based range equation [14]:…”

Section: Blended Wing-body With Boundary-layer Ingestionmentioning

confidence: 99%

“…As discussed in [14], a more appropriate terminology would be thermocompressible exergy, as it is made up of these two aspects. For a (highly) compressible flow, there is a transient region right downstream of the body where exchanges between the mechanical and thermal energy take place.…”

Section: Recoverable Exergymentioning

confidence: 99%

“…The present paper deals with the application of the exergy formulation derived in [14] for the performance assessment of a simplified BWB with a boundary-layer-ingesting propulsion system. Unpowered airframe configurations have been analyzed in [15,16], whereas the concept of wake ingestion was investigated in [17].…”

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confidence: 99%

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Exergy-Based Performance Assessment of a Blended Wing–Body with Boundary-Layer Ingestion

Arntz

Atinault

2015

AIAA Journal

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Aircraft have evolved into extremely complex systems that require adapted methodologies and tools for efficient design processes. A theoretical formulation based on exergy management is proposed for assessing the aerothermopropulsive performance of future aircraft configurations. The theoretical formulation has been numerically implemented in a FORTRAN code to postprocess Reynolds-averaged Navier-Stokes flow solutions. First, the exergy formulation is presented, and then the approach is applied to assess the performance of a simplified (two-dimensional) blended wing-body configuration with boundary-layer ingestion. The challenge of applying conventional drag/thrust bookkeeping is discussed, and the pertinence of the formulation is thereby reinforced. It is shown that this architecture wastes very little exergy in its wake/jet by exhibiting an exergy-waste coefficient lower than 3% in steady flight. Finally, heat transfer upstream of the propulsion system is found to yield an approximate 1.5% fuel saving. Overall, the benefit of the single-currency aspect of the exergy analysis is highlighted.rate of heat anergy supplied by conduction _ A tot = rate of total anergy generation _ A w = rate of anergy generation by shock waves _ A ϕ = rate of anergy generation by viscous dissipation _ A ∇T = rate of anergy generation by thermal mixing _ E p = boundary pressure-work rate _ E q = rate of heat energy supplied by conduction _ E u = streamwise kinetic-energy deposition rate _ E v = transverse kinetic-energy deposition rate _ E ϕ = rate of thermal-energy generation by viscous dissipation e = mass-specific internal energy F x = streamwise resultant force acting on the vehicle h i = mass-specific total enthalpy n = unit normal vector q = heat flux by conduction s = mass-specific entropy V = fluid-velocity vector, V ∞ ux, vy, wz W = aircraft weight Γ = weight-specific aircraft energy height δ = quantity relative to freestream, − ∞ ε = mass-specific flow exergy _ E m = rate of mechanical-exergy outflow _ E prop = rate of exergy supplied by the propulsion system _ E q = rate of heat exergy supplied by conduction _ E th = rate of thermal-exergy outflow τ = viscous stress tensor Φ = dissipation rate per unit volume · = time rate of change Subscripts A = aircraft surface adiab = adiabatic surface O = outer boundary P = propulsion-system surface w = wall ∞ = quantity at freestream conditions

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Section: Blended Wing-body With Boundary-layer Ingestionmentioning

confidence: 99%

Section: Recoverable Exergymentioning

confidence: 99%

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Exergy-Based Performance Assessment of a Blended Wing–Body with Boundary-Layer Ingestion

Arntz

Atinault

2015

AIAA Journal

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“…In a non-local analysis for far-field drag extraction, Arntz, Atinault & Merlen (2015) relate aerodynamic drag to irreversible entropy sources by combining momentum balance, thermodynamic laws and mathematical transformations. Nevertheless, mean skin friction is determined by the mean velocity profile, and the energetic interaction between the mean flow and turbulence is turbulent kinetic-energy production, not turbulent dissipation.…”

Section: Introductionmentioning

confidence: 99%

A theoretical decomposition of mean skin friction generation into physical phenomena across the boundary layer

2016

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A theoretical decomposition of mean skin friction generation into physical phenomena across the whole profile of the incompressible zero-pressure-gradient smooth-flat-plate boundary layer is derived from a mean streamwise kinetic-energy budget in an absolute reference frame (in which the undisturbed fluid is not moving). The Reynolds-number dependences in the laminar and turbulent cases are investigated from direct numerical simulation datasets and Reynolds-averaged Navier-Stokes simulations, and the asymptotic trends are consistently predicted by theory. The generation of the difference between the mean friction in the turbulent and laminar cases is identified with the total production of turbulent kinetic energy (TKE) in the boundary layer, represented by the second term of the proposed decomposition of the mean skin friction coefficient. In contrast, the analysis introduced by Fukagata et al. on a streamwise momentum budget in the wall reference frame, relates the turbulence-induced excess friction to the Reynolds shear stress weighted by a linear function of the wall distance. The wall-normal distribution of the linearly-weighted Reynolds shear stress differs from the distribution of TKE production involved in the present discussion, which consequently draws different conclusions on the contribution of each layer to the mean skin friction coefficient. At low Reynolds numbers, the importance of the buffer-layer dynamics is confirmed. At high Reynolds numbers, the present decomposition quantitatively shows for the first time that the generation of the turbulence-induced excess friction is dominated by the logarithmic layer. This is caused by the well-known decay of the relative contributions of the buffer layer and wake region to TKE production with increasing Reynolds numbers. This result on mean skin friction, with a physical interpretation relying on an energy budget, is consistent with the well-established general importance of the logarithmic layer at high Reynolds numbers, contrary to the friction breakdown obtained from the approach of Fukagata et al. based on a momentum budget. The new decomposition suggests that it may be worth investigating new drag reduction strategies focusing on TKE production and on the nature of the logarithmic layer dynamics. The decomposition is finally extended to the pressure-gradient case and to channel and pipe flows.

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“…In 2014, Arntz introduced an advancement of the power balance method [42]. The exergy balance method is similar to the power balance method, but instead of kinetic energy, it is based on the conservation of kinetic exergy within a defined control volume.…”

Section: Introductionmentioning

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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Exergy-Based Formulation for Aircraft Aeropropulsive Performance Assessment: Theoretical Development

Cited by 78 publications

References 50 publications

Exergy-Based Performance Assessment of a Blended Wing–Body with Boundary-Layer Ingestion

Exergy-Based Performance Assessment of a Blended Wing–Body with Boundary-Layer Ingestion

A theoretical decomposition of mean skin friction generation into physical phenomena across the boundary layer

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

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