Browsing by Author "Castillo Pardo, Alejandro"

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    Achieving rotorcraft noise and emissions reduction for 'Clean Sky' - The measurement of success
    (2015-12-31) Smith, Chrissy; Pachidis, Vassilios; Castillo Pardo, Alejandro; Gires, Ezanee; Stevens, Jos; Thevenot, Laurent; d'Ippolito, Roberto
    This paper describes the work done and strong interaction between Cranfield University as member of the Technology Evaluator (TE) team , Green Rotorcraft (GRC) Integrated Technology Demonstrator (ITD) and Sustainable and Green Engine (SAGE) ITD of the Clean Sky Joint Technology Initiative (JTI). The aim of Clean Sky is to develop and integrate new and innovative technologies that will hel p meeting the emission and noise reduction targets set by the Advisory Council for Aviation Research and Innovation in Europe (ACARE) for aircraft of next generation. The GRC and SAGE ITDs are responsible for developing new helicopter airframe and engine t echnologies respectively, whilst the TE has the distinctive role of assessing the environmental impact of these technologies at single flight (mission), airport and Air Transport System levels (ATS). Cranfield University as a member of the TE is responsibl e for the mission trajectory definition and for conducting the environmental performance assessments . The assessments reported herein have been performed by using a GRC - developed multi - disciplinary simulation framework called PhoeniX (Platform Hosting Oper ational and Environmental Investigations for Rotorcraft) that comprises various computational modules. These modules include a rotorcraft performance code (EUROPA), an engine performance and emissions simulation tool (GSP) and a noise prediction code (HELE NA). PhoeniX can predict the performance of a helicopter along a prescribed 4D trajectory offering a complete helicopter mission analysis. In the context of the TE assessments reported herein, three helicopter classes are examined, namely a Twin Engine Lig ht (TEL) configuration, for Emergency Medical Service (EMS) and Police missions, and a Single Engine Light (SEL) configuration for Passenger/Transport missions, and a Twin Engine Heavy (TEH) configuration for Oil & Gas missions. The different technologies assessed reflect three simulation points which are the ‘Baseline’ Year 2000 technology, ‘Reference’ Y2020 technology, without Clean Sky benefits, and finally the ‘Conceptual’, reflecting Y2020 technology with Clean Sky benefits. The results of this study i llustrate the potential that incorporated technologies possess in terms of improving performance and gas emission metrics such as fuel burn, CO2, NOx as well as the noise footprint on the ground.
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    Aeroelastic simulation of rotorcraft propulsion systems
    (2017) Castillo Pardo, Alejandro; Pachidis, Vassilios
    A close relationship between the aerospace technology level and the capability to model and simulate the physics involved during the flight has been identified throughout the aviation history. The continuous improvement in physical and mathematical models has provided a further understanding of the behaviour of the different components along with the complete vehicle. As a result, the performance modelling has experienced a large improvement. The aviation industry, which is characterised by the use of cutting edge technology, requires large investments when new concepts are introduced. The application of high fi delity simulation tools reduces considerably the investment carried out prototyping and testing. This fact is also applicable to the rotorcraft industry, where a continuous increase in the employment of helicopters has been observed throughout the last decades, expecting a sharp growth within the next 20 years. The forecasted growth in the number of helicopter operations along with the increasing concern about the environmental impact of aviation, lead the governmental bodies to set up a number of goals to reduce the carbon dioxide, nitrogen oxides, and noise emissions. Three paths were identified to reduce the environmental impact and meet the proposed goals. The fi rst one is the reduction in the number of operations. However, a sharp growth in the number of helicopter operations is expected. The second one is the optimisation of the flight procedures. Nevertheless, the potential improvement is limited. The third one is the introduction of a quieter and more,efficient type of rotorcraft. There exist two new rotorcraft con figurations which show enough potential to be studied. These are the tilt-rotor and compound helicopter. Both designs improve the cruise performance using auxiliary lift and propulsive systems, while they still exploit the vertical flight capability of helicopters. Nevertheless, the lack of reliable high fi delity models has made their development long and highly expensive. Within this context, the necessity of a simulation framework able to simulate and predict the detailed performance of novel rotorcraft con figurations is highlighted. The present work aims to lay the foundations of this comprehensive rotorcraft code by developing a computational framework for the aeroelastic simulation of propulsion systems. The tool is characterised by a high fi delity level able to predict the highly unsteady loads at a low computational cost. The fi rst characteristic makes this tool suitable for the design stage and noise calculations; whilst the second one enables its integration into multidisciplinary optimisation procedures. The development of this framework has required a considerable contribution to the knowledge in different areas of study, these included: structural dynamics, in flow aerodynamics, blade aerodynamics, aeroelasticity, and computational acceleration techniques. The individual models have been integrated into a cost efficient aeroelastic simulation framework, which has been extensively validated with experimental data. Very good and in some cases excellent correlation with the experimental measurements has been observed. The main contribution of this work has been the successful development of a computational framework for the aeroelastic simulation of rotorcraft propulsion systems. It accurately simulates and predicts the aerodynamic flow field and the unsteady loads generated by the rotor and transferred to the fuselage. It is easily expandable to account for interactions with other rotors, auxiliary lift surfaces, and fuselage bodies. The simulation tool estimates high fidelity low and high frequency aerodynamic loading, which enables the calculation of impulsive noise emissions. The framework computes accurate predictions of rotor power required, which enables its use as a validation tool for lower order models. The developed framework approximates the third level of Padfi eld's hierarchical paradigm, providing detailed aeroelastic information necessary for design purposes. The additions of parallel computing and an acceleration scheme results in a highly computationally effcient tool suitable for optimisation methodologies. Moreover, a considerable contribution has been made in terms of modelling of: coupled modal characteristics, aeroelastic simulation; computational enhancements of in flow models and investigation of the effect of the fuselage aerodynamic interference and coupled flexible blade modelling.
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    Assessment of the effect of environmental conditions on rotorcraft pollutant emissions at mission level
    (American Society of Mechanical Engineers, 2017-08-17) Ortiz-Carretero, Jesús; Castillo Pardo, Alejandro; Pachidis, Vassilios; Goulos, Ioannis
    It is anticipated that the contribution of rotorcraft activities to the environmental impact of civil aviation will increase in the forthcoming future. Due to their versatility and robustness, helicopters are often operated in harsh environments with extreme ambient conditions and dusty air. These severe conditions affect not only the engine operation but also the performance of helicopter rotors. This impact is reflected in the fuel burn and pollutants emitted by the helicopter during a mission. The aim of this paper is to introduce an exhaustive methodology to quantify the influence of the environment in the mission fuel consumption and the associated emissions of nitrogen oxides (NOx). An Emergency Medical Service (EMS) and a Search and Rescue (SAR) mission were used as a case study to simulate the effects of extreme temperatures, high altitude and compressor degradation on a representative Twin-Engine Medium (TEM) weight helicopter, the Sikorsky UH-60A Black Hawk. A simulation tool for helicopter mission performance analysis developed and validated at Cranfield University was employed. This software comprises different modules that enable the analysis of helicopter flight dynamics, powerplant performance and exhaust emissions over a user defined flight path profile. The results obtained show that the environmental effects on mission fuel and emissions are mainly driven by the modification of the engine performance for the particular missions simulated. Fluctuations as high as 12% and 40% in mission fuel and NOx emissions, respectively, were observed under the environmental conditions simulated in the present study.
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    Impact of adverse environmental conditions on rotorcraft operational performance and pollutant emissions
    (ASME, 2017-08-23) Ortiz Carretero, Jesus; Castillo Pardo, Alejandro; Goulos, Ioannis; Pachidis, Vassilios
    It is anticipated that the contribution of rotorcraft activities to the environmental impact of civil aviation will increase in the future. Due to their versatility and robustness, helicopters are often operated in harsh environments with extreme ambient conditions. These severe conditions not only affect the performance of the engine but also affect the aerodynamics of the rotorcraft. This impact is reflected in the fuel burn and pollutants emitted by the rotorcraft during a mission. The aim of this paper is to introduce an exhaustive methodology to quantify the influence adverse environment conditions have in the mission fuel consumption and the associated emissions of nitrogen oxides (NOx). An emergency medical service (EMS) and a search and rescue (SAR) mission are used as case studies to simulate the effects of extreme temperatures, high altitude, and compressor degradation on a representative twin-engine medium (TEM) weight helicopter, the Sikorsky UH-60A Black Hawk. A simulation tool for helicopter mission performance analysis developed and validated at Cranfield University was employed. This software comprises different modules that enable the analysis of helicopter flight dynamics, powerplant performance, and exhaust emissions over a user-defined flight path profile. For the validation of the models implemented, extensive comparisons with experimental data are presented throughout for rotorcraft and engine performance as well as NOx emissions. Reductions as high as 12% and 40% in mission fuel and NOx emissions, respectively, were observed for the “high and cold” scenario simulated at the SAR role relative to the same mission trajectory under standard conditions.
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    Modelling and analysis of coupled flap-lag-torsion vibration characteristics helicopter rotor blades
    (Sage Publications, 2016-11-13) Castillo Pardo, Alejandro; Goulos, Ioannis; Pachidis, Vassilios
    This paper presents the development of a mathematical approach targeting the modelling and analysis of coupled flap-lag-torsion vibration characteristics of non-uniform continuous rotor blades. The proposed method is based on the deployment of Lagrange’s equation of motion to the three-dimensional kinematics of rotor blades. Modal properties derived from classical-beam and torsion theories are utilized as assumed deformation functions. The formulation, which is valid for hingeless, freely hinged and spring-hinged articulated rotor blades, is reduced to a set of closed-form integral expressions. Numerical predictions for mode shapes and natural frequencies are compared with experimental measurements, non-linear finite element analyses and multi-body dynamics analyses for two small-scale hingeless rotor blades. Excellent agreement is observed. The effect of different geometrical parameters on the elastic and inertial coupling is assessed. Additionally, the effect of the inclusion of gyroscopic damping is evaluated. The proposed method, which is able to estimate the first seven coupled modes of vibration in a fraction of a second, exhibits excellent numerical stability. It constitutes a computationally efficient alternative to multi-body dynamics and finite element analysis for the integration of rotor blade flexible modelling into a wider comprehensive rotorcraft tool.