Résumé:
The present study focuses on the design and numerical analysis of a dual-bell
propulsion nozzle, and compares its performance and flow-field characteristics with those
of a conventional single-bell nozzle having the same area ratio at the throat and exit. The
I.
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I.
Abdou, M.
Flow-Field Design and Analysis within Single and Dual-Bell Propulsion Nozzles
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dual-bell nozzle, known for its altitude-adaptive capabilities, was modeled to exploit its two
distinct operating modes: a sea-level mode with flow separation, and a high-altitude mode
with flow attachment along the walls. Steady-state simulations were carried out using
“ANSYS Fluent” platform that solves the Reynolds-Averaged Navier–Stokes (RANS)
equations in 2-D axisymmetric form, with the k-ω SST turbulence model used to close the
system. Key flow parameters such as pressure and Mach distributions along the
performance characteristics, were evaluated. Compared to the single-bell configuration,
the dual-bell nozzle exhibits more stable flow behavior under over-expanded conditions
and delivers better overall thrust efficiency under varying ambient conditions. This
comparative study highlights the potential of dual-bell nozzles to enhance the performance
of the first stages of next-generation launch vehicles.
