An Integrated Approach for the Multidisciplinary Design of Optimum Rotorcraft Operations

This paper presents an integrated methodology for the comprehensive assessment of com bined rotorcraft-powerplant systems at mission level. Analytical evaluation of existing and conceptual designs is carried out in terms of operational performance and environ mental impact. The proposed approach comprises a wide-range of individual modeling theories applicable to rotorcraft flight dynamics and gas turbine engine performance. A novel, physics-based, stirred reactor model is employed for the rapid estimation of nitro gen oxides (NOx) emissions. The individual mathematical models are implemented within an elaborate numerical procedure, solving for total mission fuel consumption and associ ated pollutant emissions. The combined approach is applied to the comprehensive analy sis of a reference twin-engine light (TEL) aircraft modeled after the Eurocopter Bo 105 helicopter, operating on representative mission scenarios. Extensive comparisons with flight test data are carried out and presented in terms of main rotor trim control angles and power requirements, along with general flight performance charts including payload-range diagrams. Predictions of total mission fuel consumption and NOx emis sions are compared with estimated values provided by the Swiss Federal Office of Civil Aviation (FOCA). Good agreement is exhibited between predictions made with the physics-based stirred reactor model and experimentally measured values ofNOx emission indices. The obtained results suggest that the production rates of NOx pollutant emissions are predominantly influenced by the behavior of total air inlet pressure upstream of the combustion chamber, which is affected by the employed operational procedures and the time-dependent all-up mass (AUM) of the aircraft.It is demonstrated that accurate esti mation of on-board fuel supplies ahead offlight is key to improving fuel economy as well as reducing environmental impact. The proposed methodology essentially constitutes an enabling technology for the comprehensive assessment of existing and conceptual rotor craft-powerplant systems, in terms of operational performance and environmental impact.

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“…This is a direct outcome of the anticipated traffic augmentation [3]. This is a direct outcome of the anticipated traffic augmentation [3].…”

Section: Introductionmentioning

confidence: 90%

A Multidisciplinary Approach for the Comprehensive Assessment of Integrated Rotorcraft–Powerplant Systems at Mission Level

Goulos

Ali

Tzanidakis

et al. 2014

Journal of Engineering for Gas Turbines and Power

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“…As regards option (b), Brooker [5] Contributed by the Aircraft Engine Committee of ASME for publication in the elaborates that the time frame between the conception of a prototype aircraft design and the achievement of airworthiness certification can reach up to 50 years time. Thus, in order to address the targets set by ACARE for the year 2020, emphasis needs currently to be placed towards the design of optimum operational procedures [6].…”

Section: Introductionmentioning

confidence: 99%

“…[6] utilizes an LHD DOE method coupled with RSMs structured using interpolation based on radial basis functions (RBF) [10]. The design exploration method deployed in Ref.…”

Section: Introductionmentioning

confidence: 99%

Rotorcraft Engine Cycle Optimization at Mission Level

Goulos

Hempert

Sethi

et al. 2013

Journal of Engineering for Gas Turbines and Power

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Rotorcraft Engine Cycie Optimization at iVIission LevelThis work investigates the potential to reduce fuel consumption associated with civil rotorcraft operations at mission level, through optimization of the engine design point cycle parameters. An integrated simulation framework, comprising models applicable to rotorcraft flight dynamics, rotor blade aeroelasticity, and gas turbine performance, has been deployed. A comprehensive and computationally efficient optimization strategy, utilizing a novel particle-swarm method, has been structured. The developed methodology has been applied on a twin-engine light and a twin-engine medium rotorcraft configuration. The potential reduction in fuel consumption has been evaluated in the context of designated missions, representative of modern rotorcraft operations. Optimal engine design point cycle parameters, in terms of total mission fuel consumption, have been obtained. Pareto front models have been structured, describing the optimum interrelationship between maximum shaft power and mission fuel consumption. The acquired results suggest that, with respect to technological limitations, mission fuel economy can be improved with the deployment of design specifications leading to increased thermal efficiency, while simultaneously catering for sufficient performance to satisfy aii-worthiness certification requirements. The developed methodology enables the identification of optimum engine design specifications using a single design criterion; the respective trade-off between fuel economy and payload-range capacity, through maximum contingency shaft power, that the designer is prepared to accept. Aircraft-Engine Design and Trajectory Optimization.A substantial amount of literature is available in the public domain, dealing with the investigation of operational procedures for aircraft and rotorcraft, potentially optimum in terms of fuel bum and environmental impact. D'Ippolito et al. [2] demonstrated the applicability of design of experiment (DOE) methods coupled with response surface models (RSM) to the optimization of a category A take-off maneuver for a twin-engine light rotorcraft. Their modeling approach included the use of the EUROPA rotorcraft flight dynamics code [7], the engine performance simulation tool GSP [8], and the noise propagation analysis tool HELENA [9]. Their optimization strategy included the deployment of a Latin hypercube design (LHD) DOE approach coupled with least square fitting Taylor polynomials to structure the required RSMs.

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“…In Europe, a number of environmental goals have been set by the Advisory Council for Aeronautics Research (ACARE), which include reductions in carbon dioxide (CO 2 ) and nitrogen oxides (NOx) emissions of the order of 50% and 80%, respectively (Ref. 1). For this reason, the need to address these targets pushes the rotary-wing community toward implementing specific actions to reduce engine fuel consumption.…”

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A Methodology for Determining the Optimal Rotational Speed of a Variable RPM Main Rotor/Turboshaft Engine System

Misté¹,

Benini²,

Garavello³

et al. 2015

J Am Helicopter Soc

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Variable speed rotors represent an innovative research field for the development of new rotorcraft designs. Issues related to employing a main rotor variable speed are numerous and require an interdisciplinary approach. For this reason, a preliminary effort has been made to understand the performance implications of coupling helicopter trim and turboshaft engine simulations. Following this, two different models of a UH-60 Black Hawk helicopter and a GE T700 turboshaft engine are implemented and validated against experimental data. Then, an optimization algorithm is employed to find the optimal main rotor speed with the aim of minimizing fuel consumption. Different simulation cases are analyzed to quantify the benefits related to the optimal main rotor speed depending on flight condition, altitude, and helicopter gross weight. It is found that coupling both the helicopter and engine model is necessary to adequately determine the correct rotational speed corresponding to minimum fuel consumption. More than 10% fuel saving is shown to be feasible. The results obtained employing a variable speed main rotor are broadly discussed, and future possible applications of the methodology are suggested. Nomenclature

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An Integrated Approach for the Multidisciplinary Design of Optimum Rotorcraft Operations

Cited by 18 publications

References 12 publications

A Multidisciplinary Approach for the Comprehensive Assessment of Integrated Rotorcraft–Powerplant Systems at Mission Level

A Multidisciplinary Approach for the Comprehensive Assessment of Integrated Rotorcraft–Powerplant Systems at Mission Level

Rotorcraft Engine Cycle Optimization at Mission Level

A Methodology for Determining the Optimal Rotational Speed of a Variable RPM Main Rotor/Turboshaft Engine System

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