Browsing by Author "Mutangara, Ngonidzashe E."

Now showing 1 - 7 of 7
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    Fundamental considerations in the design and performance assessment of propulsive fuselage aircraft concepts
    (Cambridge University Press (CUP), 2025-03) Moirou, Nicolas G. M.; Mutangara, Ngonidzashe E.; Sanders, Drewan S.
    Propulsive fuselage aircraft complement the two under-wing turbofans of current aircraft with an embedded propulsion system within the airframe to ingest the energy-rich fuselage boundary layer. The key design features of this embedding are examined and related to an aero-propulsive performance assessment undertaken in the absolute reference frame which is believed to best evaluate these effects with intuitive physics-based interpretations. First, this study completes previous investigations on the potential for energy recovery for different fuselage slenderness ratios to characterise the aerodynamics sensitivity to morphed fuselage-tail design changes and potential performance before integrating fully circumferential propulsors. Its installation design space is then explored with macro design parameters (position, size and operating conditions) where an optimum suggests up to 11% fuel savings during cruise and up to 16% when introducing compact nacelles and re-scaling of the under-wing turbofans. Overall, this work provides valuable insights for designers and aerodynamicists on the potential performance of their concepts to meet the environmental targets of future aircraft.
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    Potential for energy recovery from boundary-layer ingesting actuator disk propulsion
    (AIAA, 2024-01-26) Mutangara, Ngonidzashe E.; Smith, Lelanie; Craig, Kenneth J.; Sanders, Drewan S.
    The theoretical benefits of highly integrated propulsion systems are highlighted herein by assessing the potential for energy recovery utilization using actuator disk propulsion. Decomposing aerodynamic forces into thrust and drag for closely integrated bodies, particularly those employing boundary-layer ingestion, becomes challenging. In this work, a mechanical energy-based approach was taken using the power balance method. This allowed the performance to be analyzed through the mechanical flow power in the fluid domain, disregarding the need for any explicit definition of thrust and drag. Through this, the benefit of boundary-layer ingestion was observed from a wake energy perspective as a decrease in the downstream mechanical energy deposition and associated viscous dissipation. From a propulsion perspective, the reduction in power demand necessary to produce propulsive force indicated the possibility of power savings by utilizing the energy contained within the ingested boundary-layer flow.
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    Potential for energy recovery of a nonadiabatic subsonic airfoil
    (American Institute of Aeronautics and Astronautics (AIAA), 2025) Lister-Symonds, Joseph E.; Mutangara, Ngonidzashe E.; Lamprakis, Ioannis; Sanders, Drewan S.
    This paper investigates the effect of wall temperature and flow conditions on the potential for energy recovery of the NACA0012 airfoil. A work–energy balance has been derived from the governing equations for moving control volumes for a body in dynamic equilibrium, aerodynamically decoupled from its propulsive source. The formulation has been applied to an extensive test matrix of computational fluid dynamics cases, with steady level flight imposed and wall temperature, angle of attack, Reynolds number, and Mach number varied independently. The decomposition of the wake energy shows explicitly that the near-field work of the body manifests as global energy constituents, viscous dissipation, and baroclinic work. The analysis identifies the conditions and underlying mechanisms that minimize and maximize the potential for energy recovery, revealing that there are synergistic opportunities for tightly coupled airframe and propulsor configurations with waste heat to reject.
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    Potential for energy recovery of unpowered configurations using power balance method computations
    (AIAA, 2021-07-30) Mutangara, Ngonidzashe E.; Smith, Lelanie; Craig, Kenneth J.; Sanders, Drewan S.
    New aircraft developments are made to improve aircraft performance and efficiency. One such method is integrating propulsion into the airframe. This allows for boundary-layer ingestion, which shows promise of significant power benefits. However, these benefits are difficult to quantify as the propulsion system and aircraft body become meticulously integrated. The thrust and drag are coupled and cannot be defined separately, making conventional performance analysis methods inapplicable. The power balance method (PBM) addresses this by quantifying aircraft performance in terms of mechanical flow power and change in kinetic-energy rate. The primary focus of this work was to perform computational studies implementing the PBM on unpowered aerodynamic bodies to evaluate their respective drag contributions. A secondary study was also conducted to quantify the energy recovery potential of various bodies using a potential for energy recovery factor. The computational fluid dynamics case studies showed that drag obtained using the PBM agreed to within 2% of conventional momentum-based approaches. Maximal energy recovery potential was consistently observed at the trailing ends of the geometries, with values ranging between 9 and 12%.
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    Synergistic aerodynamic force assessment through an extended exergy approach
    (Cranfield University, 2023-06) Mutangara, Ngonidzashe E.; Laskaridis, Panagiotis; Sanders, Drewan S.
    Drag decomposition using energy and exergy-based methods has shown large utility for aerodynamic performance assessment through their flow-field decompositions into different physical mechanisms. A particularly significant advantage of these methods is their ability to identify recoverable energy, which describes the available energy imparted to the flow by the aircraft as it traverses through the fluid. This type of assessment is not possible with traditional momentum analysis. Thus, energy/exergy analysis uniquely evaluates the potential benefits of wake energy utilisation for thrust production through novel architectures such as boundary layer ingestion. The velocity decomposition approach has introduced notable improvements to this analysis framework. This allows for a phenomenological drag decomposition into reversible and irreversible components by splitting the velocity field into its isentropic and non-isentropic contributions within the flow. From this, the reversible drag originating from the bulk flow can be obtained through the isentropic field, whilst the non-isentropic field provides the irreversible dissipative drag arising from the boundary layer and wake zones. The work conducted in this thesis aims to improve the velocity decomposition approach by combining it with partial pressure field analysis, enabling the decomposition of pressure into Euler and dissipative parts, previously not achievable with velocity decomposition alone. Assessment in this manner improves the evaluation of recoverable energy by identifying the additional pressure work potential within the dissipative field. Additionally, the unification extends energy/exergy-based analysis principles to the near- field, providing a unique decomposition capable of evaluating the local accumulation of viscous drag through dissipative pressure and skin friction, whilst the induced drag is assessed from the non-dissipative pressure.
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    Thrust/drag decomposition using partial pressure fields
    (Association Aeronautique et Astronautique de France (3AF), 2023-03-31) Hart, Pierce L.; Mutangara, Ngonidzashe E.; Sanders, Drewan S.; Schmitz, Sven
    The accurate prediction of aircraft performance requires a robust definition of thrust/drag accounting. Traditional nacelle-pylon configurations have been treated as separate entities which are combined linearly; however, this is not feasible for embedded propulsion systems which have a higher degree of interaction than traditional designs. With the apparent shift to embedded propulsion systems in the N+3 generation of aircraft, of which boundary layer ingestion technology is a driving factor, improving our understanding of propulsion system interactions with an air-frame has never been more important. Since many of these interactions occur close to the body, a near-field decomposition method, partial pressure fields, is employed in CFD to provide insight as to the interactive aerodynamics of an embedded propulsion system.
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    A unified partial pressure field and velocity decomposition approach toward improved energetic aerodynamic force decompositions
    (Association Aeronautique et Astronautique de France (3AF), 2023-03-31) Mutangara, Ngonidzashe E.; Sanders, Drewan S.; Laskaridis, Panagiotis; Hart, Pierce L.; Schmitz, Sven
    Drag decomposition through energy and exergy-based methods has been shown to have a variety of advantages. One of these is identifying and quantifying the recoverable energy within a flow field. This describes the available energy that can be used to produce thrust through systems such as boundary layer ingestion. Another advantage highlighted from prior work is that the velocity decomposition approach can split the flow field into its isentropic and non-isentropic contributions. This provides region-specific formulations for drag assessment, wherein the isentropic field is associated with contributions originating from the bulk flow and the non-isentropic field with the shear layer. This paper aims to assess the performance of a modified form of the velocity decomposition approach for transonic flows. This modification involves unification with partial pressure field analysis, which provides better flow field separability due to the added decomposition of the pressure field.