Over-expanded separation transitions of single expansion ramp nozzle in the accelerating and decelerating processes

Yu, Yang

doi:10.1016/j.ast.2019.105674

Cited by 14 publications

(2 citation statements)

References 34 publications

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“…On the other hand, the residual values of parameters such as the continuity equation, the velocity components, and the energy equation had to be reduced to less than 10 −4 . The viscous model is the renormalization group (RNG) k-ε model, which is a well-validated turbulence model for predicting the separation flow field of the nozzle [27][28][29][30]. The simulation model has the same conditions as the experiment, and the settings are listed in Table 1.…”

Section: Numerical Simulation Methods and Validationmentioning

confidence: 99%

“…Lee et al [26] numerically studied the flow separation mechanism of a thrust-optimized parabolic nozzle in high-altitude experiments, and the observed flow characteristics showed that the separation pattern and the transition process were very different from those in sea-level experiments. In previous projects conducted by the authors [27,28], the impact of NPR and external Mach numbers on the flow separation patterns of an overexpanded SERN was extensively examined. The results showed that FSS became the most common separation pattern considering the external flow field, which was in contrast to the results under the static state.…”

Section: Introductionmentioning

confidence: 99%

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The Influence of External Flow Field on the Flow Separation of Overexpanded Single-Expansion Ramp Nozzle

Yu,

Mao,

et al. 2023

Aerospace

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Flow separation and transitions of separation patterns are common phenomena of nozzles working with a wide Mach range. The maximum thrust method is applied to design the single-expansion ramp nozzle (SERN) for specific operating conditions. The nozzle is used to numerically simulate the transition processes of separation patterns under the linear change in the external flow Mach number and the actual trajectory take-off condition of a rocket-based combined cycle (RBCC), to investigate the mechanism through which the external flow field influences the separation pattern transition during acceleration. The computational fluid dynamics (CFD) method is briefly introduced, followed by experimental validation. Then, the design procedure of SERN is described in detail. The simulation results indicate that as the external Mach number increases, the flow field in the nozzle undergoes transitions from RSS (ramp) to FSS, and finally exhibits a no-flow separation pattern. The rate at which the external Mach number varies has little effect on the transition principle of the nozzle flow separation patterns, but it has a significant effect on the critical Mach number of the transition points. The external flow field of the nozzle has an airflow accumulation effect during acceleration, which can delay the transition of the flow separation pattern.

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Section: Numerical Simulation Methods and Validationmentioning

confidence: 99%