Browsing by Author "Enconniere, Julien"

Now showing 1 - 4 of 4
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    The impact of clean sky technology on future 3500 lb single engine light rotorcraft
    (ISABE, 2017-09-08) Enconniere, Julien; Ortiz Carretero, Jesus; Goulos, Ioannis; Pachidis, Vassilios; Smith, C.; Stevens, J.; d'Ippolito, R.; Thevenot, Laurent
    This manuscript describes a collaborative research effort between members of the Clean Sky Joint Technology Initiative (JTI), within the broader area of novel rotorcraft engine technology and rotorcraft operations. The Clean Sky JTI was created as a public/private partnership between the European Commission and the aeronautical industry. The paper assesses the impact of innovative engine technologies to be integrated into the next generation of rotorcraft and evaluates their potential towards meeting the ACARE 2020 goals. The focus is on the lower segment of the light helicopter class with a particular interest in the performance of two innovative powerplants: an advanced turboshaft with Lean Premixed Prevaporised (LPP) combustor design and a supercharged diesel cycle engine. In order to evaluate their benefits alongside other Clean Sky technologies, a multi-disciplinary rotorcraft performance analysis framework (PhoeniX) is employed. Two variants of the same light helicopter platform with year 2020 technology plus Clean Sky innovations are modelled, named hereafter as Single Engine Light (SEL) Y2020 and High Compression Engine (HCE) Y2020, respectively. A turboshaft engine-powered helicopter, representative of year 2000 technology (SEL Y2000) is also modelled and used as reference. Payload-Range diagrams (PR) of the three vehicles were generated. The HCE Y2020 reached a maximum range 83% greater than the SEL counterparts. The gaseous emissions of the helicopters were also evaluated over three notional scenarios representative of light helicopter activities. The HCE Y2020 emitted 60% less carbon dioxide (CO2) and 63% less nitrogen oxides (NOx) than the SEL Y2000. The SEL Y2020 emitted on average 19% and 49% less CO2 and NOx, respectively, compared with the SEL Y2000. It was also observed that the NOx production rate of the LPP technology integrated in the SEL Y2020 combustor depends strongly on engine power setting. At certain power settings, the SEL Y2020 emitted less NOx than the HCE Y2020 even though the HCE Y2020 emitted less NOx over the complete mission. The direct comparison between SEL Y2020 and HCE Y2020 highlighted the superior performance of the HCE engine over the gas turbine for the mission types and rotorcraft class simulated.
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    Mission optimisation for a conceptual coaxial rotorcraft for taxi applications
    (Elsevier, 2017-10-31) Enconniere, Julien; Ortiz-Carretero, Jesús; Pachidis, Vassilios
    This paper presents the development and an application of a multidisciplinary methodology for the preliminary design assessment of compound coaxial rotorcraft with a counter-rotating rotor system and a rear-mounted propeller. A comprehensive optimisation strategy is deployed to evaluate the environmental and operational benefits of the aforementioned rotorcraft architecture. The code is validated against experimental data prior to the application of the methodology to the evaluation of a conceptual vehicle for intercity taxi applications. Response Surface Models (RSMs) are generated to mimic the rotorcraft performance in order to accelerate the optimisation process. The effects of the defined mission input parameters such as cruise speed, altitude, climb rate or mission length are evaluated. Pareto fronts for fuel burn, NOx emissions and mission duration are obtained. The method was applied to a hypothetical scenario of mission length ranging from 50 to 300 km. Best estimate mission scenario are selected from the Pareto fronts, providing on average 23%, 20%, and 13% simultaneous reductions in mission duration, fuel burn, and NOx emissions when compared to a conventional flight procedure. The picked scenarios coincide with the fuel optimised mission scenarios for each mission length, thus the multi-disciplinary environment was not required. Besides, an “improved” mission procedure is outlined, defining the mission characteristics independently of the mission's length. This procedure yields on average 22%, 14%, and 8% reductions in mission duration, fuel burn, and NOx emissions, respectively.
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    Mission performance analysis of a conceptual coaxial rotorcraft for air taxi applications
    (Elsevier, 2017-06-15) Enconniere, Julien; Ortiz Carretero, Jesus; Pachidis, Vassilios
    The rotorcraft industry has recently shown a new interest in compound rotorcraft as a feasible alternative to tackle the rapid growth of civil aviation activities and associated environmental impact. Indeed, aircraft contribution to the global emissions of CO2CO2, NOxNOx, and noise are driving the development of innovative technologies and vehicles. At present, compound rotorcraft architectures are regarded by the industry as promising platforms that can potentially increase productivity at a reduced environmental cost. In order to quantify the benefits of compound rotorcraft, this paper details the performance analysis of a coaxial counter-rotating rotor configuration with a pusher propeller. A comprehensive approach targeting the assessment of the aforementioned rotorcraft design for civil applications is presented herein. The methodology developed encompasses a rotorcraft flight dynamics simulation module and an engine performance module, coupled with a gaseous emissions prediction tool for environmental impact studies. They have been integrated together to constitute a standalone performance simulation framework and verified with the performance calculations of Harrington's “rotor 1” and the Sikorsky X2TD. The method is then applied to evaluate the performance of a conceptual coaxial rotorcraft, during a notional inter-city air taxi mission, in terms of cruise altitude, speed, and range, overall mission time and environmental impact. The several trade-offs between these parameters highlight the need for an integrated optimisation process. Besides, the concept demonstrates the benefits of the compound rotorcraft architecture with a best range speed reaching 90 m/s leading to reduced response times and increase of round trips in a given time. As a consequence, operators will need fewer vehicles and heliports to cover the same areas. This outcome is highly attractive in the current growing market.
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    Scheduled flight control system of tilt-rotor VTOL PAV
    (AIAA, 2023-01-19) Kang, Namuk; Whidborne, James F.; Lu, Linghai; Enconniere, Julien
    This paper develops the longitudinal flight control scheme for the tilt-rotor VTOL Aston Martin Volante Vision. It is envisaged that the aircraft will be flown by a "flight-naive pilot" who is less well-trained than normal. The conversion corridor is developed and the optimum tilt schedule is determined using the minimum power curve and numerical optimisation to encompass hover, conversion and cruise flight without manipulating the rotor tilt angle. The methodology is found to be unique because two conversion schedules were integrated to reflect critical factors for conversion and stationary configurations. A proportional-integral-derivative (PID) controller has been designed with a suitable inceptor response and control allocation for a flight-naïve pilot while a blending schedule has unified different response types at the low and high speed into a single control system. The PID controllers are evaluated using design guidelines of ADS-33E-PRF and MIL-STD-1797A. The conversion flight simulation shows that the suggested longitudinal stability and control augmentation system (SCAS) are expected to reduce the pilot workload and improve handling qualities making performance and handling more suitable for a flight-naive pilot.