| 1. |
- Axelsson, Lars-Uno, 1979, et al.
(author)
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Evaluation of the flow in an intermediate turbine duct at off-design conditions
- 2008
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In: ICAS 2008, 26th international congress of the aeronautical sciences, Alaska, August 2008. - 9781605607153 ; 2, s. 3286-3295
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Conference paper (peer-reviewed)abstract
- Intermediate turbine ducts are used in modern turbofan engines for connecting the highpressure turbine with the low-pressure turbine. The demands for engines with higher by-pass ratios require these ducts to be more "aggressive", i.e., to have a larger radial off-set and to be shorter. However, the flow in the intermediate turbine ducts are complex and therefore difficult to predict. Therefore a better understanding of the flow physics is necessary and measurements for CFD validation are needed. This paper presents time-averaged measurements of the flow in a state-at-the-art intermediate turbine duct with an upstream high-pressure turbine present. The investigation focuses on the intermediate turbine duct flow field development for different turbine conditions. The measurements consist of area traverses with a five-hole pressure probe at different axial locations within the intermediate turbine duct. In addition, a discussion of the endwall static pressure distribution and the overall pressure losses for the different conditions are done.
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| 2. |
- Bérard, Adrien, et al.
(author)
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Development and validation of a next-generation conceptual aero-structural sizing suite
- 2008
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In: ICAS Secr. - Int. Counc. Aeronaut. Sci. ICAS. - 9781605607153 ; , s. 1718-1727
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Conference paper (peer-reviewed)abstract
- An overview of a novel variable-fidelity aerostructural computational suite targeted for prediction at the conceptual design phase is presented herein. The computational suite consists of two primary modules known as CADac (Computer Aided Design Aircraft) and NeoCASS (Next generation Conceptual Aero-Structural Sizing Suite). The methodology is based upon the integration of geometry construction, aerodynamic and structural analysis codes that combine depictive, computational, analytical, and semiempirical methods, validated in an aircraft design environment. The aerodynamics sub-space is analyzed using methods based upon a Vortex-Lattice Method used to examine large structural deformations, a Doublet Lattice Method in order to predict flutter boundaries in the subsonic speed regime, and, an Euler based method to cater for identification of flutter points in the transonic regime. A quasi-analytical method that provides accurate weights estimation and refined prediction of airframe moments of inertia data has also been introduced, thus facilitating a more comprehensive investigation of the quasi-static aeroelastic problem. To illustrate the new computational system capabilities, the methodology was applied to a complete flexible structural model of the B747-100 transport aircraft. The quasianalytical weight prediction of the NeoCASS suite was found to generate an accuracy of less than 0.5% error compared to published results.
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| 3. |
- Tarkian, Mehdi, 1982-, et al.
(author)
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Aircraft Parametric 3D Modeling and Panel Code Analysisfor Conceptual Deisgn
- 2008
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In: International Council of the Aeronautical Sciencess ICAS, 2008. - Anchorage, Alaska, USA : International Council of the Aeronautical Sciences (ICAS). - 9781605607153 ; , s. 159-167
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Conference paper (other academic/artistic)abstract
- The ever fast growing information technology is enabling a re-definition of the early stages of aircraft design which have been restricted to mostly statistical and empirical approaches because of lengthy and costly simulation times. A novel framework is being developed at Linköping University offering greater comprehension by enabling a holistic view of the aircraft systems with a multidisciplinary analysis approach, involving a centralized easy to use interface. This paper will depict the modules involving an aerodynamic panel code solver integrated to a parametric CAD model. The connection between these tools is made fully automatic, meaning that any modification on the CAD model will with a press of button be aerodynamically analyzed in the panel solver, including re-meshing and re-writing of a input file and finally re-distributing the output file to all other modules involved in the framework.
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