@misc{SainHoeschler, author = {Sain, Chetan Kumar and H{\"o}schler, Klaus}, title = {Aerodynamic Assessment of Nozzle Area Variation by Core Fairing Modulation}, series = {CEAS Aeronautical Journal}, volume = {8}, journal = {CEAS Aeronautical Journal}, number = {3}, issn = {1869-5590}, doi = {10.1007/s13272-017-0253-4}, pages = {493 -- 504}, abstract = {Aerodynamic assessment of nozzle area variation by core fairing modulation on the way towards the goals of ACARE 2020 and Flightpath 2050 [1], a next potential step in flight engine technology is to develop engines with by-pass ratios (BPR) far beyond the current levels of 10 to 12. These new engine concepts can have BPRs of up to 20 and require a significant step forward in low pressure system technologies. The European Union supports within the 7th Framework the research activities for these new low pressure systems through the program ENOVAL [2]. Such a new low pressure technology can be achieved through an innovative fan design with a low fan pressure ratio and a radically increased fan diameter compared to the current conventional turbofan engine. The aerodynamic stability of such large fans is most likely very sensitive against backpressure variations. For this reason the backpressure regulation of such large fan, specially during take-off operation, can be achieved through the introduction of a Variable Area Fan Nozzle [VAFN]. This paper describes the aerodynamic study of a particular VAFN concept. This concept offers the variation in fan nozzle throat-area by the displacement of the inner fixed structure (IFS) (also known as core fairing structure). The aim of the assessment was to perform a comparative aerodynamic study at different design configurations. These configurations were derived by varying the design parameters such as the location of section plane (divides the IFS into front and rear block) and the position of the rotational axis. The range of the area change for different flight cases was defined by the engine owner under the ENOVAL program. For each design configuration, the geometries for all the flight cases with their required variation in the nozzle throat area were developed. For the initial study phase the aero assessment a 2D axis-symmetric flow was considered and the airflow from the vent nozzle and core nozzle were included. At this stage, the flight cases with the maximum variation in throat area (e.g. max take-off and top of climb) and the nominal cruise case without area change were studied. Three major performance parameters, the thrust coefficient, nozzle drag coefficient and the after-body drag were calculated. The effects of the gaps and steps (resulting from the overlapping between the IFS segments) on the performance parameters were examined. A comparative result was produced in which the different design parameters of the VAFN were ranked. With the help of few iterations, the best possible design configuration was accessed. At the final stage, the detailed aerodynamic studies on the selected design configuration were performed for the whole range of area variation, including the cruise case with different power loops and the maximum area changes with the variations in the day temperature. [1] Advisory Council for Aviation Research and Innovation in Europe (ACARE) with its targets for CO2 emission- and noise reduction by year 2020 for civil European aircraft industries to be more innovative, sustainable and highly competitive till year 2050 (Flightpath 2050) www.acare4europe.com/. [2] European 7th Framework Program ENOVAL(ENgine mOdule VALidators) http://www.enoval.eu/.}, language = {en} } @inproceedings{GrasseltHoeschlerSain, author = {Grasselt, David and H{\"o}schler, Klaus and Sain, Chetan Kumar}, title = {Fluid-Structure Interaction With a Fully Integrated Multiphysics Environment}, series = {Proceedings of the ASME Fluids Engineering Division Summer Meeting - 2017, presented at the ASME 2017 Fluids Engineering Division Summer Meeting, July 30-August 3, 2017, Waikoloa, Hawaii, USA, Volume 1B}, booktitle = {Proceedings of the ASME Fluids Engineering Division Summer Meeting - 2017, presented at the ASME 2017 Fluids Engineering Division Summer Meeting, July 30-August 3, 2017, Waikoloa, Hawaii, USA, Volume 1B}, publisher = {ASME}, address = {New York, NY}, isbn = {978-0-7918-5805-9}, doi = {10.1115/FEDSM2017-69078}, pages = {8}, abstract = {The paper is focusing on Fluid-Structure Interaction (FSI) process modelling to look for the aero-elastic equilibrium with commercial software packages. The center of intention is to prove whether Ansys Workbench is capable to handle industrial size FSI applications on the one side and to identify possible excitation regions in the example case on the other. The three steps taken to come to a thermal-enhanced bidirectional fluid-structure approach within a fully integrated (monolithic) multiphysics environment are explained: aerodynamic assessment, thermo-structure mechanical setup and unidirectional coupling, as well as bidirectional coupling. Each subchapter describes the specific challenges, how they are solved and which results can be obtained or expected. The paper is focusing on the setup of a bidirectional process chain and does not set the thematic priority on detailed modelling and its results.}, language = {en} } @inproceedings{SainHoeschler, author = {Sain, Chetan Kumar and H{\"o}schler, Klaus}, title = {Comparative Assessment between Variable Area Fan Nozzle Concepts at Inner and Outer By-Pass Duct Surfaces}, series = {ISABE-2017-21342, 03.-08. September 2017, Manchester (UK)}, booktitle = {ISABE-2017-21342, 03.-08. September 2017, Manchester (UK)}, publisher = {ISABE}, pages = {10}, abstract = {The next generation of civil turbofan engines target the by-pass ratios of up to 20:1, which are far beyond the current levels of 10:1 to 12:1. These jet engines require a significant step forward in low-pressure system technologies. The European Union supports within the 7th Framework the research activities for these new low-pressure systems through the program ENOVAL [1]. Such a new low-pressure technology can be achieved through an innovative fan design with a low fan pressure ratio and a radically increased fan diameter compared to the current conventional turbofan engines. The aerodynamic stability of such large fans is quite likely very sensitive against backpressure variations in the by-pass duct. For this reason, the back-pressure regulation of such a large fan, especially during the take-off operation, can be achieved through the introduction of a Variable Area Fan Nozzle (VAFN). On the given geometry, two potential design spaces were studied and the conceptual designs of two VAFN concepts were created. This paper presents a comparative study between both the concepts following the requirements of different attributes. These involve the performance assessment, structural design study, and a preliminary assessment of the design features for integration into the nacelle or in the core fairing structure. For the comparison, the clean nozzle, without any modulation of the BPD aero lines, was taken as the reference case. The VAFN assessments were carried out on two VAFN positions, over- and under-area, considering the maximum take-off and maximum climb flight conditions respectively. For the selected concepts, CFD trade studies were executed in order to compare the nozzle performance, in which three main governing design parameters i.e. discharge-, thrust performance coefficient, and drag, were examined. This research has received funding from the European Union's 7th Framework Program under grant agreement number 604999.}, language = {en} } @inproceedings{SainHoeschlerMischke, author = {Sain, Chetan Kumar and H{\"o}schler, Klaus and Mischke, Marcel}, title = {Concept study of variable area fan nozzle for UHBPR turbofan engine}, series = {22nd International Symposium on Air Breathing Engines (ISABE-2015-20213), 25.-30. Oktober 2015, Phoenix (AZ, USA)}, booktitle = {22nd International Symposium on Air Breathing Engines (ISABE-2015-20213), 25.-30. Oktober 2015, Phoenix (AZ, USA)}, publisher = {ISABE}, pages = {8}, language = {en} }