An investigation of the swirling flow in a spinning end-burning rocket
The purpose of this study was to determine the swirling flowfield which develops at various spin rates in the chamber of a spinning end-burning rocket. Cold flow experiments employing a porous plate to represent the propellant surface were conducted. The experiments were designed to simulate dynamically the conditions in a typical cylindrical rocket combustion chamber. Pressure measurements at the plate and in the flow were correlated with smoke traces to arrive at a physical description of the flowfield in which solid-body rotation gives way to a high-speed vortex in the chamber at sufficiently high motor spin rates. The experimental correlation of the onset of this flow transition with a critical value of the Rosby number is in agreement with a theoretical analysis, and it is concluded that the vortex development is a characteristic of the inviscid rotating flow. The experiments also indicate that significant interaction between the vortex and the propellant surface is little affected by chamber length or nozzle entrance shape.