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  • 2000-2004  (2)
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  • 1
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    A Subsonic Aircraft Design Optimization With Neural Network and Regression Approximators (2004)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: The Flight-Optimization-System (FLOPS) code encountered difficulty in analyzing a subsonic aircraft. The limitation made the design optimization problematic. The deficiencies have been alleviated through use of neural network and regression approximations. The insight gained from using the approximators is discussed in this paper. The FLOPS code is reviewed. Analysis models are developed and validated for each approximator. The regression method appears to hug the data points, while the neural network approximation follows a mean path. For an analysis cycle, the approximate model required milliseconds of central processing unit (CPU) time versus seconds by the FLOPS code. Performance of the approximators was satisfactory for aircraft analysis. A design optimization capability has been created by coupling the derived analyzers to the optimization test bed CometBoards. The approximators were efficient reanalysis tools in the aircraft design optimization. Instability encountered in the FLOPS analyzer was eliminated. The convergence characteristics were improved for the design optimization. The CPU time required to calculate the optimum solution, measured in hours with the FLOPS code was reduced to minutes with the neural network approximation and to seconds with the regression method. Generation of the approximators required the manipulation of a very large quantity of data. Design sensitivity with respect to the bounds of aircraft constraints is easily generated.
    Keywords: Aircraft Design, Testing and Performance
    Type: NASA/TM-2004-213059 , AIAA Paper 2004-4606 , E-14504 , 10th Multidisciplinary Analysis and Optimization Conference; Aug 30, 2004 - Sep 01, 2004; Albany, NY; United States
    Format: application/pdf
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    NASA TECHNICAL REPORTS
  • 2
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    A Probabilistic Assessment of NASA Ultra-Efficient Engine Technologies for a Large Subsonic Transport (2004)
    In:  CASI
    Details
    Publication Date: 2019-07-13
    Description: NASA's Ultra Efficient Engine Technology (UEET) program features advanced aeropropulsion technologies that include highly loaded turbomachinery, an advanced low-NOx combustor, high-temperature materials, intelligent propulsion controls, aspirated seal technology, and an advanced computational fluid dynamics (CFD) design tool to help reduce airplane drag. A probabilistic system assessment is performed to evaluate the impact of these technologies on aircraft fuel burn and NOx reductions. A 300-passenger aircraft, with two 396-kN thrust (85,000-pound) engines is chosen for the study. The results show that a large subsonic aircraft equipped with the UEET technologies has a very high probability of meeting the UEET Program goals for fuel-burn (or equivalent CO2) reduction (15% from the baseline) and LTO (landing and takeoff) NOx reductions (70% relative to the 1996 International Civil Aviation Organization rule). These results are used to provide guidance for developing a robust UEET technology portfolio, and to prioritize the most promising technologies required to achieve UEET program goals for the fuel-burn and NOx reductions.
    Keywords: Aircraft Design, Testing and Performance
    Type: GT2004-53485 , E-14435 , ASME Turbo Expo 2004; Jun 14, 2004 - Jun 17, 2004; Vienna; Austria
    Format: application/pdf
    Location Call Number Expected Availability
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    NASA TECHNICAL REPORTS
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