Slag mass accumulation in spinning solid rocket motors

Abstract

A series of specific solid propellant rocket motors are evaluated and their slag mass accumulation is computed when operating in strong acceleration environments. It is shown that the configuration of the propellant burning surface during the last 10 s of burning has a very strong effect on slag formation. Motors with front-end burning grains at burnout have maximum slag retention potential, whereas motors with the grain burning inside potential slag pockets (e.g., the buried nozzle cavities) do not accumulate any slag. The effects of the internal flowfield are significant because they are the direct result of the grain configuration. It is concluded that if slag is a problem, selective grain design will tend to minimize it or to eliminate it completely.