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Effect of Ambient pressure fluctuations on dual-bell transition behavior

IR@NAL: CSIR-National Aerospace Laboratories, Bangalore


Field	Value

Title	Effect of Ambient pressure fluctuations on dual-bell transition behavior

Creator	Verma, SB Stark, R Haidn, O

Subject	Aeronautics (General)

Description	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 backpressure fluctuations 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.

Publisher	American Institute of Aeronautics and Astronautics

Date	2014

Type	Journal Article PeerReviewed

Format	application/pdf application/pdf

Identifier	http://nal-ir.nal.res.in/12230/1/ja545.pdf http://nal-ir.nal.res.in/12230/2/ja545post.pdf Verma, SB and Stark, R and Haidn, O (2014) Effect of Ambient pressure fluctuations on dual-bell transition behavior. Journal of Propulsion and Power, 30 (5). pp. 1192-1198. ISSN 0748-4658

Relation	http://nal-ir.nal.res.in/12230/