Performance penalties associated with infrared (IR)-signature suppression (IRSS), e.g., increased engine back pressure, weight, drag, cost, and complexity, can shift the engine operating point to higher combustion temperatures. Extra weight degrades aircraft flight performance in terms of reduced range, higher length needed for takeoff, reduced maneuverability, etc. Lift-induced drag penalty due to increased weight shifts the aircraft gas turbine engine operating point to a higher combustion temperature. But the divergent section of the convergent-divergent (C-D) nozzle gives the extra thrust up to optimal flow expansion, which more than compensates the increased lift-induced drag corresponding to its weight. Thus, for the same thrust, an engine with a C-D nozzle operates at a lower combustion temperature than with a convergent nozzle. This study theoretically addresses the net effect of incorporation of a divergent section (considering its weight penalty) on aircraft performance for two cases: (i) shift in engine operating point to lower combustion temperature, for the same thrust; (ii) fixed engine operating point, with increased thrust. For both cases, the IR-signature in the boresight of the C-D nozzle with increasing divergent-section length up to optimal flow expansion is compared with that of a convergent nozzle in 1.9-2.9 μm (SWIR), 3-5 μm (MWIR), and 8-12 μm (LWIR) bands. It is found that visibility is a more important parameter in the 8-12 μm band, as compared to the 1.9-2.9 μm and 3-5 μm bands.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Infrared Signature of Combat Aircraft Incorporating Weight Penalty due to the Divergent Section of the Convergent-Divergent Nozzle


    Additional title:

    Sae Technical Papers


    Contributors:

    Conference:

    Automotive Technical Papers ; 2022



    Publication date :

    2021-09-01




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    Infrared Signature of Combat Aircraft Incorporating Weight Penalty due to the Divergent Section of the Convergent-Divergent Nozzle

    Baranwal, Nidhi / Mahulikar, Shripad P. | British Library Conference Proceedings | 2021


    Convergent-divergent nozzle

    ZAHID HUSSAIN | European Patent Office | 2016

    Free access

    Convergent-divergent nozzle flows.

    KLIEGEL, J. R. / QUAN, V. | AIAA | 1968


    Convergent-divergent nozzle flows

    Kliegel, J.R. / Quan, V. | Engineering Index Backfile | 1968


    Convergent-divergent nozzle flows

    Kliegel, J. R. / Quan, V. | NTRS | 1966