Generalized Model for Vehicle Thermodynamic Loss Management

Roth, Bryce Alexander; Mavris, Dimitri N.

doi:10.2514/2.3058

Cited by 11 publications

(5 citation statements)

References 5 publications

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“…If more thrust is being delivered than drag, the aircraft gains either altitude or velocity. In agreement with [10,20,21], the aircraft acts as an accumulator of mechanical energy that is released during descent. The mechanical-exergy outflow:…”

Section: Review Of the Formulationmentioning

confidence: 91%

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: Review Of the Formulationmentioning

confidence: 91%

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

Arntz

Atinault

2015

AIAA Journal

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“…Thus the systems engineer has a need for a loss accounting method that enables systematic analysis of loss where system wide consequences of design trades can be evaluated. This premise led to the development of generalized models for vehicle thermodynamic loss management by Roth and Mavris [94], where differential loss models can be built of all aircraft sub-systems (Fig. 2), and the sources of work can be modelled against the vehicle losses under a unifying metric.…”

Section: Design and Analysis Of Commercial Aerospace Systemsmentioning

confidence: 99%

Adopting exergy analysis for use in aerospace

Hayes

Lone

Whidborne

et al. 2017

Progress in Aerospace Sciences

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Thermodynamic analysis methods, based on an exergy metric, have been developed to improve system efficiency of traditional heat driven systems such as ground based power plants and aircraft propulsion systems. However, in more recent years interest in the topic has broadened to include applying these second law methods to the field of aerodynamics and complete aerospace vehicles. Work to date is based on highly simplified structures, but such a method could be shown to have benefit to the highly conservative and risk averse commercial aerospace sector. This review justifies how thermodynamic exergy analysis has the potential to facilitate a breakthrough in the optimization of aerospace vehicles based on a system of energy systems, through studying the exergy-based multidisciplinary design of future flight vehicles.

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“…A certain amount of exergy is required to do this mission work, and the 'overhead' (exergy destruction, waste irreversibilities) should be minimised. For example Bejan and Siems (2) showed a linkage between aircraft size reduction and minimum exergy destroyed and Figliola et al (4) showed a connection between system weight minimisation and minimal exergy destruction. Roth and Mavris (4) demonstrated the potential for using thermodynamic work potential in aerospace vehicle design.…”

Section: Introductionmentioning

confidence: 99%

“…For example Bejan and Siems (2) showed a linkage between aircraft size reduction and minimum exergy destroyed and Figliola et al (4) showed a connection between system weight minimisation and minimal exergy destruction. Roth and Mavris (4) demonstrated the potential for using thermodynamic work potential in aerospace vehicle design. They suggest that "at the most fundamental level, it is the usage and loss of thermodynamic work potential that drives virtually every aspect of a vehicle's design and performance."…”

Section: Introductionmentioning

confidence: 99%

System integration of high intensity energy subsystems – a thermal management challenge

Pratt

Moorhouse

2008

Aeronaut. j.

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Current and future Air Force weapons systems lack the necessary power and cooling capacity to provide full systems level capability as a result of energy and thermal management limitations. Cooling capacity of fuel is already fully utilised leaving little room for additional cooling needs. Additionally, increasing speed, power, and miniaturisation of future systems continue to stress any thermal management capability that we can now deliver. Thus, the focus of this paper is a conceptual assessment of the key energy and thermal management technologies to meet the future energy challenges. It presents an overview of the current state of the art and also possible future research.

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Generalized Model for Vehicle Thermodynamic Loss Management

Cited by 11 publications

References 5 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

Adopting exergy analysis for use in aerospace

System integration of high intensity energy subsystems – a thermal management challenge

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