An experimental investigation was conducted to study the effect of ambient pressure fluctuations on the dual-bell transition behavior. Ambient or backpressure fluctuations of different frequencies (1.0, 1.5, and 3 Hz) were artificially introduced inside the high-altitude simulation chamber using three magnetic valves. The dual-bell transition behavior was found to be very sensitive to backpressurefluctuations of magnitude > 20 % , which triggered a flip-flop phenomenon that was observed to continue as long as the fluctuations prevailed. Increasing the throttling-up rate also did not seem to help much in achieving a stable dual-bell transition within the scope of the present tests. This, too, was not favorable, as it can lead to a delay in transition. These test results suggested that the dual-bell nozzle can present problems in real-flight operation, especially when the launcher experiences the buffeting phase of flight. The solution perhaps lies in increasing the dual-bell stability parameter to a value greater than the magnitude of backpressure fluctuations so as to avoid the nozzle pressure ratio range that will set the dual bell into a nonstop flip-flop mode during buffeting.


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    Title :

    Effect of Ambient Pressure Fluctuations on Dual-Bell Transition Behavior


    Contributors:
    Verma, S. B. (author) / Stark, R. (author) / Haidn, O. (author)

    Published in:

    Publication date :

    2014-07-15


    Size :

    7 pages




    Type of media :

    Article (Journal)


    Type of material :

    Electronic Resource


    Language :

    English




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