Single-Phase Internal Flowfield Validation with an Experimental Solid Rocket Motor Model

摘要

Incorporating a submerged nozzle for solid propellant rocket motors, the resulting cavity formed in the vicinity of the nozzle integration part enhances the entrapment of liquid residues of the combustion and leads to the accumulation of slag with a considerable mass. As a first step for the slag accumulation assessment, an experimental and numerical investigation of the single-phase internal flowfield is performed and the numerical tool is validated. The measurements are carried out in a cold-gas simplified model in which the flow is injected from the forward end (no wall injection). Simultaneously, the experimental configuration is simulated numerically with the help of a commercial solver (CFD-ACE+). The experimental results allowed the full characterization of the complex recirculation zone downstream of the inhibitor model and in the cavity. It was also demonstrated that the airflow in the cavity is slightly altered in case the gas-slag interface is represented either as a rigid or a liquid. The time-averaged statistical results of the three-dimensional simulation in the midspan plane compare very well to the experimental database, ensuring a satisfactory validation. The mean streamlines close to the walls, plotted from the computational fluid dynamics field, allow better understanding of the flow structures. The analysis reveals a two-dimensional flowfield for the studied geometry with locally some three-dimensional behaviors, especially along the main recirculation bubble interface.