Experimental and analytical design verification of the dual-bell concept

Hagemann, G.; Terhardt, M.; Haeseler, D.; Frey, Manuel

doi:10.2514/6.2000-3778

Cited by 17 publications

(3 citation statements)

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“…The application of commonly used separation criteria derived from conventional nozzles gave reasonable results when applied to dual-bell nozzles [7]. The time needed for the transition and the side loads induced by the transition were also examined [8]. Typical timescales needed for the transition were less than 10 ms for both constant-pressure and overturned pressure contours.…”

Section: Short Bibliographical Surveymentioning

confidence: 99%

“…For both types of nozzle extensions, a strong hysteresis was observed with respect to the transition nozzle pressure ratio (NPR tr ) with a higher value for the startup. This hysteresis e¨ect was found to be an obstacle for a potential pulsation between the two dual-bell §ow regimes [8]. The e¨ect of the nozzle extension length on the NPR transition and the transition time was studied [9].…”

Section: Short Bibliographical Surveymentioning

confidence: 99%

“…14) that the §ow expands at the junction just before crossing a separation shock. The fact that the §ow separates not at, but downstream of the wall in §ection is referred in [8] to as ¤sneak transition.¥ For ground conditions, the atmospheric pressure being 1 bar, the nozzle pressure ratio will be NPR = 50 (see dashed line in blue , Fig. 14); the base nozzle will run in slightly overexpanded §ow regime.…”

Section: Wall Pressure Pro¦les Around Mode Transitionmentioning

confidence: 99%

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Wall pressure and thrust of a dual bell nozzle in a cold gas facility

Reijasse

Coponet

Luyssen

et al. 2011

Progress in Propulsion Physics

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A dual-bell nozzle has been tested in the ONERA-R2Ch wind tunnel within the CNES PERSEUS program. The wall pressure distributions and the thrust for the two §ow regimes have been characterized in the nozzle pressure ratio (NPR) range from 51 up to 597. A hysteresis on the transition NPR between the two §ow regimes has been observed according to the evolution of NPR. The duration for the switch between the two §ow regimes is less than 10 ms. The hysteresis of about 20% on the NPR has also a direct e¨ect on the thrust. The total thrust of the dual-bell nozzle becomes higher than the thrust of the isolated base nozzle without extension for NPR > 1500. The hysteresis phenomenon has been modeled with the use of supersonic separation criteria and by making the assumption that incipient separation occurs immediately after the transition for increasing NPRs, while e¨ective separation occurs just before the transition for decreasing NPRs.

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Section: Short Bibliographical Surveymentioning

confidence: 99%

Section: Short Bibliographical Surveymentioning

confidence: 99%

Section: Wall Pressure Pro¦les Around Mode Transitionmentioning

confidence: 99%

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