Study on wall pressure and hysteresis behaviors of a novel dual-bell nozzle

The dual-bell nozzle is a kind of altitude adaptive nozzle for improving the performance of space launchers as well as future reusable launch vehicles. Numerical investigations have been conducted on a planar dual-bell nozzle to illustrate the flow characteristics at sea level, “sneak” transition, and altitude modes, respectively. Findings from computational fluid dynamics have been contrasted with experimental data from the open literature. The normalized pressure distributions along the dual-bell nozzle wall for different turbulence models are compared to the pressure measurements taken during the experiment by fixing the nozzle pressure ratio (NPR) at 29.8. The NPR value gradually rises across a large range from 6 to 55 to explore the evolution of the flow characteristics. The pressure distributions along the nozzle wall and shock position have been investigated. The hysteretic behaviors occur in dual-bell nozzles close to the contour inflection. The wall pressure and hysteresis behaviors have been expounded in detail.