Theses by Aurélien ARNTZ
A new exergy-based formulation is derived for the assessment of the aerothermopropulsive perform... more A new exergy-based formulation is derived for the assessment of the aerothermopropulsive performance of civil aircraft. The choice of exergy is motivated by its ability to provide a well-established and consistent framework for the design of aerospace vehicles. The output of the derivation process is an exergy balance between the exergy supplied by a propulsion system or by heat transfer, the mechanical equilibrium of the aircraft, and the exergy outflow and destruction within the control volume. The theoretical formulation is subsequently numerically implemented in a Fortran code named ffx for the post-processing of CFD-RANS flow solutions.
Unpowered airframe configurations are examined with grid refinement studies and a turbulence model sensitivity analysis is performed. A numerical correction is introduced and calibrated to obtain an accuracy similar to the near-field drag method. The code is thereby validated against well-tried methods of drag prediction and wind-tunnel tests, when available.
The investigation of powered configurations demonstrates the ability of the approach for assessing the performance of configurations with aerothermopropulsive interactions. First, the formulation is validated for the simple case of a turbojet engine for which consistent figures of merit are exhibited. The method is also proved robust for assessing the overall performance of a boundary layer ingesting propulsion system placed on the upper surface of a simplified blended wing-body architecture. Moreover, this configuration enables the investigation of thermopropulsive interactions by the transfer of heat upstream of the propulsion system.
Subsequently, the integration of a heat exchanger on a commercial aircraft is examined for which the exergy point of view provides guidelines for an efficient design. The ability of the formulation to consistently assess all these types of subsystems is a clear benefit of this method.
Bookmarks Related papers MentionsView impact
This study has been made in the framework of a French national research project called AVECA wher... more This study has been made in the framework of a French national research project called AVECA where ONERA is responsible for the aerodynamic shape optimization of an initial blended-wing-body configuration provided by Airbus France. The project consists in designing viable flying wing geometries in terms of aerodynamic cruise and take-off performance. Recently an optimization was carried out by ONERA to increase the performance at cruise of the initial design. While high improvements in terms of lift-to-drag ratio and equilibrium have been reached, it has been determined that this configuration
would encounter issues at low-speed.
The optimization process used at that time was not able to take into account low speed criteria which are essential on this type of configurations for obtaining an aircraft with good handling qualities at take-off. The purpose of this study is to define and take into account low speed criteria to perform a complete optimization of the configuration.
The impact of the elevons has been evaluated by Airbus France using low fidelity tools and needs to be accurately evaluated with high fidelity RANS computations. Their effectiveness in take-off and cruise conditions is investigated to determine their impact on the aerodynamic performance.
Cruise optimizations are then performed to determine the initial geometry, the parametrization as well as the optimization scenario to provide the best results. These conclusions enabled to optimize the configuration at cruise with a low-speed constraint, whose assessment validated it as providing high cruise performance as well as acceptable take-off characteristics.
Bookmarks Related papers MentionsView impact
Journal Articles by Aurélien ARNTZ
Paper available upon request!
Authors: A. Arntz, O. Atinault, and A. Merlen
Aircraft have evolv... more Paper available upon request!
Authors: A. Arntz, O. Atinault, and A. Merlen
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.
Read More: http://arc.aiaa.org/doi/abs/10.2514/1.J054072?journalCode=aiaaj
Bookmarks Related papers MentionsView impact
Paper available upon request!
Authors: Aurélien Arntz and David Hue
Aircraft have evolved into ... more Paper available upon request!
Authors: Aurélien Arntz and David Hue
Aircraft have evolved into extremely complex systems that require adapted methodologies and tools for efficient design processes. A theoretical formulation based on exergy management has been recently proposed by Arntz et al. for assessing the aerothermopropulsive performance of future aircraft configurations. The present article focuses on the validation of its numerical implementation in a FORTRAN code for the postprocessing of Reynolds-averaged Navier–Stokes flow solutions. The flow around the wing-body NASA Common Research Model is assessed in terms of anergy destruction. A 2 MW work potential associated with the lift-induced vortices is identified in the wake of the airplane. Subsequently, a six-level grid convergence study enables determining the robustness and accuracy of the exergy postprocessing code. The introduction and calibration of a numerical correction allows to account for the spurious numerical vortex dissipation and to obtain an accuracy similar to the traditional near-field drag method. Finally, the postprocessing code is validated for drag prediction against computational fluid dynamics and experimental wind-tunnel data.
Bookmarks Related papers MentionsView impact
http://arc.aiaa.org/doi/abs/10.2514/1.J053467?journalCode=aiaaj
Aircraft have evolved into ext... more http://arc.aiaa.org/doi/abs/10.2514/1.J053467?journalCode=aiaaj
Aircraft have evolved into extremely complex systems that require adapted methodologies and tools for an efficient
design process. A theoretical formulation based on exergy management is proposed for assessing the aeropropulsive
performance of future aircraft configurations. It consists of the combination of a momentum balance and a fluid flow
analysis involving the first and second laws of thermodynamics. The exergy supplied by the propulsion system and its
partial destruction within the control volume is associated with the aircraft mechanical equilibrium. Characterization
of the recoverable mechanical and thermal outflows is made along with the identification of the irreversible
phenomena that destroy their work potential. Restriction of the formulation to unpowered configurations yields
connections to some well-known far-field drag expressions and shows that their underlying theory can be related to
exergy considerations. Because the exergy balance does not rely on the distinction of thrust and drag, it is especially
suitable for the performance evaluation of highly integrated aeropropulsive concepts like boundary-layer ingestion.
Bookmarks Related papers MentionsView impact
Conference Papers by Aurélien ARNTZ
2th ISABE Conference, 2019
First, adaptation of an exergy balance initially derived for steady external flows is made to stu... more First, adaptation of an exergy balance initially derived for steady external flows is made to study turbomachine applications. Illustrative examples are given to describe the physical meaning of each term followed by a discussion. Then, application to various components of a propulsion system is proposed focusing on loss mechanisms. Finally, a few perspectives and related developments are discussed.
Bookmarks Related papers MentionsView impact
53rd 3AF International Conference on Applied Aerodynamics, 2018
Within the framework of the French DGA's NECTAR project, SAFRAN Aircraft Engines has access durin... more Within the framework of the French DGA's NECTAR project, SAFRAN Aircraft Engines has access during a test phase to the ONERA's ffx (Far-Field eXergy) tool. This software has been applied to various configurations including those presented in this paper: long duct mixed flow nozzles. On this kind of nozzles, primary and secondary flows are mixed at the confluence before the exhaust. This mixing aims at lower acoustic signature as well as fuel consumption.
A component referred to as a mixer is often added to maximize the mixing. The flow through this component as well as the mixing action itself being complex, it requires optimisation during the design process. As a consequence, an exergy analysis is performed on CFD calculations using a formulation adapted from the one derived for external flows in the PhD Thesis of A. Arntz [1], with applications in [2-5].
This paper presents one of the two first applications of this approach in SAFRAN Aircraft Engines; the second being an assessment of blade performance [6]. One of the challenges in applying this analysis to such devices is to relate the various terms of the exergy balance to more established performance indicators for the design engineer. This is achieved by studying the sensitivity of these terms to geometrical changes, engine speed and thermal exchanges.
Bookmarks Related papers MentionsView impact
53rd 3AF International Conference on Applied Aerodynamics, 2018
The paper presents a new exergy-based analysis method for turbomachines internal flow. This metho... more The paper presents a new exergy-based analysis method for turbomachines internal flow. This method applies to periodic flow inside a turbomachine. After a presentation of the system studied and of the concept of exergy, a balance equation formulation for internal, periodic flow is derived. Then, the results obtained by applying the formulation to computational fluid dynamics (CFD) results, thanks to the ONERA (Office national d'études et de recherches aérospatiales) ffx (Far Field eXegy) tool, are shown. High pressure compressor stator and rotor blades, and a high pressure turbine distributor blade are studied and compared.
Bookmarks Related papers MentionsView impact
Michael Meheut, ONERA; Aurelien Arntz, ONERA; Gerald Carrier, ONERA
Bookmarks Related papers MentionsView impact
Aurélien Arntz, ONERA; Olivier Atinault, ONERA; Daniel Destarac, ONERA
Bookmarks Related papers MentionsView impact
Aircraft have evolved into extremely complex systems that require adapted tools to allow efficie... more Aircraft have evolved into extremely complex systems that require adapted tools to allow efficient design processes. A new formulation based on an exergy balance is under development at ONERA for assessing the aeropropulsive performance of future aircraft configurations. A control volume analysis is performed to relate the exergy supplied by the propulsion system, its partial destruction within the control volume and the aircraft mechanical equilibrium. The formulation does not rely on the expression of thrust and drag and is therefore especially suitable for the performance evaluation of aircraft configurations with boundary layer ingestion (BLI). A first step towards such applications is the investigation of a more academical conguration consisting in the ingestion by a powered nacelle of the complete wake of a simplied fuselage. Investigation is made via 3D RANS computations and it is shown that the benefit is due the recovery of the mechanical exergy present in the fuselage wake.
Bookmarks Related papers MentionsView impact
Papers by Aurélien ARNTZ
AIAA Journal, Jun 1, 2015
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
32nd AIAA Applied Aerodynamics Conference, Jun 13, 2014
Bookmarks Related papers MentionsView impact
AIAA Journal, 2016
Bookmarks Related papers MentionsView impact
AIAA Journal, Dec 1, 2015
Bookmarks Related papers MentionsView impact
HAL (Le Centre pour la Communication Scientifique Directe), Mar 24, 2014
Bookmarks Related papers MentionsView impact
30th AIAA Applied Aerodynamics Conference, Jun 25, 2012
This paper aims at presenting aerodynamic optimizations carried out at Onera in collaboration wit... more This paper aims at presenting aerodynamic optimizations carried out at Onera in collaboration with Airbus on the AVECA flying wing configuration using the adjoint approach. Several optimizations were conducted in order to define an optimization scenario to maximize the aerodynamic performance of the AVECA configuration in cruise conditions under geometric and aerodynamic constraints at fixed wing planform. This scenario was then applied to several wing planforms in order to define the influence of the re-optimization to compute the sensitivities of the aerodynamic performance to several wing planform parameters. Finally, a cruise optimization was conducted taking into account a low-speed constraint (Take-off rotational criterion) in order to define a viable flying wing configuration at cruise but also in low-speed conditions.
Bookmarks Related papers MentionsView impact
Bookmarks Related papers MentionsView impact
Uploads
Theses by Aurélien ARNTZ
Unpowered airframe configurations are examined with grid refinement studies and a turbulence model sensitivity analysis is performed. A numerical correction is introduced and calibrated to obtain an accuracy similar to the near-field drag method. The code is thereby validated against well-tried methods of drag prediction and wind-tunnel tests, when available.
The investigation of powered configurations demonstrates the ability of the approach for assessing the performance of configurations with aerothermopropulsive interactions. First, the formulation is validated for the simple case of a turbojet engine for which consistent figures of merit are exhibited. The method is also proved robust for assessing the overall performance of a boundary layer ingesting propulsion system placed on the upper surface of a simplified blended wing-body architecture. Moreover, this configuration enables the investigation of thermopropulsive interactions by the transfer of heat upstream of the propulsion system.
Subsequently, the integration of a heat exchanger on a commercial aircraft is examined for which the exergy point of view provides guidelines for an efficient design. The ability of the formulation to consistently assess all these types of subsystems is a clear benefit of this method.
would encounter issues at low-speed.
The optimization process used at that time was not able to take into account low speed criteria which are essential on this type of configurations for obtaining an aircraft with good handling qualities at take-off. The purpose of this study is to define and take into account low speed criteria to perform a complete optimization of the configuration.
The impact of the elevons has been evaluated by Airbus France using low fidelity tools and needs to be accurately evaluated with high fidelity RANS computations. Their effectiveness in take-off and cruise conditions is investigated to determine their impact on the aerodynamic performance.
Cruise optimizations are then performed to determine the initial geometry, the parametrization as well as the optimization scenario to provide the best results. These conclusions enabled to optimize the configuration at cruise with a low-speed constraint, whose assessment validated it as providing high cruise performance as well as acceptable take-off characteristics.
Journal Articles by Aurélien ARNTZ
Authors: A. Arntz, O. Atinault, and A. Merlen
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.
Read More: http://arc.aiaa.org/doi/abs/10.2514/1.J054072?journalCode=aiaaj
Authors: Aurélien Arntz and David Hue
Aircraft have evolved into extremely complex systems that require adapted methodologies and tools for efficient design processes. A theoretical formulation based on exergy management has been recently proposed by Arntz et al. for assessing the aerothermopropulsive performance of future aircraft configurations. The present article focuses on the validation of its numerical implementation in a FORTRAN code for the postprocessing of Reynolds-averaged Navier–Stokes flow solutions. The flow around the wing-body NASA Common Research Model is assessed in terms of anergy destruction. A 2 MW work potential associated with the lift-induced vortices is identified in the wake of the airplane. Subsequently, a six-level grid convergence study enables determining the robustness and accuracy of the exergy postprocessing code. The introduction and calibration of a numerical correction allows to account for the spurious numerical vortex dissipation and to obtain an accuracy similar to the traditional near-field drag method. Finally, the postprocessing code is validated for drag prediction against computational fluid dynamics and experimental wind-tunnel data.
Aircraft have evolved into extremely complex systems that require adapted methodologies and tools for an efficient
design process. A theoretical formulation based on exergy management is proposed for assessing the aeropropulsive
performance of future aircraft configurations. It consists of the combination of a momentum balance and a fluid flow
analysis involving the first and second laws of thermodynamics. The exergy supplied by the propulsion system and its
partial destruction within the control volume is associated with the aircraft mechanical equilibrium. Characterization
of the recoverable mechanical and thermal outflows is made along with the identification of the irreversible
phenomena that destroy their work potential. Restriction of the formulation to unpowered configurations yields
connections to some well-known far-field drag expressions and shows that their underlying theory can be related to
exergy considerations. Because the exergy balance does not rely on the distinction of thrust and drag, it is especially
suitable for the performance evaluation of highly integrated aeropropulsive concepts like boundary-layer ingestion.
Conference Papers by Aurélien ARNTZ
A component referred to as a mixer is often added to maximize the mixing. The flow through this component as well as the mixing action itself being complex, it requires optimisation during the design process. As a consequence, an exergy analysis is performed on CFD calculations using a formulation adapted from the one derived for external flows in the PhD Thesis of A. Arntz [1], with applications in [2-5].
This paper presents one of the two first applications of this approach in SAFRAN Aircraft Engines; the second being an assessment of blade performance [6]. One of the challenges in applying this analysis to such devices is to relate the various terms of the exergy balance to more established performance indicators for the design engineer. This is achieved by studying the sensitivity of these terms to geometrical changes, engine speed and thermal exchanges.
Papers by Aurélien ARNTZ
Unpowered airframe configurations are examined with grid refinement studies and a turbulence model sensitivity analysis is performed. A numerical correction is introduced and calibrated to obtain an accuracy similar to the near-field drag method. The code is thereby validated against well-tried methods of drag prediction and wind-tunnel tests, when available.
The investigation of powered configurations demonstrates the ability of the approach for assessing the performance of configurations with aerothermopropulsive interactions. First, the formulation is validated for the simple case of a turbojet engine for which consistent figures of merit are exhibited. The method is also proved robust for assessing the overall performance of a boundary layer ingesting propulsion system placed on the upper surface of a simplified blended wing-body architecture. Moreover, this configuration enables the investigation of thermopropulsive interactions by the transfer of heat upstream of the propulsion system.
Subsequently, the integration of a heat exchanger on a commercial aircraft is examined for which the exergy point of view provides guidelines for an efficient design. The ability of the formulation to consistently assess all these types of subsystems is a clear benefit of this method.
would encounter issues at low-speed.
The optimization process used at that time was not able to take into account low speed criteria which are essential on this type of configurations for obtaining an aircraft with good handling qualities at take-off. The purpose of this study is to define and take into account low speed criteria to perform a complete optimization of the configuration.
The impact of the elevons has been evaluated by Airbus France using low fidelity tools and needs to be accurately evaluated with high fidelity RANS computations. Their effectiveness in take-off and cruise conditions is investigated to determine their impact on the aerodynamic performance.
Cruise optimizations are then performed to determine the initial geometry, the parametrization as well as the optimization scenario to provide the best results. These conclusions enabled to optimize the configuration at cruise with a low-speed constraint, whose assessment validated it as providing high cruise performance as well as acceptable take-off characteristics.
Authors: A. Arntz, O. Atinault, and A. Merlen
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.
Read More: http://arc.aiaa.org/doi/abs/10.2514/1.J054072?journalCode=aiaaj
Authors: Aurélien Arntz and David Hue
Aircraft have evolved into extremely complex systems that require adapted methodologies and tools for efficient design processes. A theoretical formulation based on exergy management has been recently proposed by Arntz et al. for assessing the aerothermopropulsive performance of future aircraft configurations. The present article focuses on the validation of its numerical implementation in a FORTRAN code for the postprocessing of Reynolds-averaged Navier–Stokes flow solutions. The flow around the wing-body NASA Common Research Model is assessed in terms of anergy destruction. A 2 MW work potential associated with the lift-induced vortices is identified in the wake of the airplane. Subsequently, a six-level grid convergence study enables determining the robustness and accuracy of the exergy postprocessing code. The introduction and calibration of a numerical correction allows to account for the spurious numerical vortex dissipation and to obtain an accuracy similar to the traditional near-field drag method. Finally, the postprocessing code is validated for drag prediction against computational fluid dynamics and experimental wind-tunnel data.
Aircraft have evolved into extremely complex systems that require adapted methodologies and tools for an efficient
design process. A theoretical formulation based on exergy management is proposed for assessing the aeropropulsive
performance of future aircraft configurations. It consists of the combination of a momentum balance and a fluid flow
analysis involving the first and second laws of thermodynamics. The exergy supplied by the propulsion system and its
partial destruction within the control volume is associated with the aircraft mechanical equilibrium. Characterization
of the recoverable mechanical and thermal outflows is made along with the identification of the irreversible
phenomena that destroy their work potential. Restriction of the formulation to unpowered configurations yields
connections to some well-known far-field drag expressions and shows that their underlying theory can be related to
exergy considerations. Because the exergy balance does not rely on the distinction of thrust and drag, it is especially
suitable for the performance evaluation of highly integrated aeropropulsive concepts like boundary-layer ingestion.
A component referred to as a mixer is often added to maximize the mixing. The flow through this component as well as the mixing action itself being complex, it requires optimisation during the design process. As a consequence, an exergy analysis is performed on CFD calculations using a formulation adapted from the one derived for external flows in the PhD Thesis of A. Arntz [1], with applications in [2-5].
This paper presents one of the two first applications of this approach in SAFRAN Aircraft Engines; the second being an assessment of blade performance [6]. One of the challenges in applying this analysis to such devices is to relate the various terms of the exergy balance to more established performance indicators for the design engineer. This is achieved by studying the sensitivity of these terms to geometrical changes, engine speed and thermal exchanges.