Numerical study on flow and thrust characteristics of a planar expansion deflection nozzle

DOI:	10.11809/bqzbgcxb2024.08.010
Keywords:	planar expansion deflection nozzle; altitude compensation; flow field characteristics; operating mode; numerical simulation
Abstract:	Compared the flow field characteristics and thrust performance of an expansion deflection nozzle (ED) with a conventional convergent divergent nozzle (CD) with the same expansion ratio at a pressure ratio between 10 and 150 by numerical simulation,with the increasing pressure ratio, the supersonic flow area in the ED nozzle increases, the shear layer is close to the axis, and the reattached shock wave is generated. The viscous recirculation area is gradually isolated from the outside atmosphere, and the flow mode changes from ‘open wake’ to ‘closed wake’. The transition between the two flow modes is marked by a sudden drop in basement pressure. The performance of the designed ED nozzle is better than that of the CD nozzle under all calculation conditions, and the performance advantage is more obvious at lower pressure ratio. There are two main reasons for the improvement of ED nozzle performance: 1) no wall flow separation occurs, reducing the over expansion loss; 2) Under the condition of relatively low pressure, when the first shock wave from the pintle reaches nozzle shroud, a large amount of flow encounter compressive turning, resulting in increased wall pressure, which leads to improved performance.
Issue:	Vol. 45 No. 8 (2024)
Published:	2024-09-02
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