Research progress on solid-fueled Scramjet

The solid-fueled Scramjet is an interesting option for supersonic combustion ramjet. It shows significant advantages such as simple fuel supply and compactness, avoiding the complex system of tanks and pipelines that encountered in liquid-fueled Scramjets. The solid-fueled Scramjet could be the simplest air-breathing engine for the hypersonic flight regime. This paper presents a comprehensive and systematic review of the research progress on solid-fueled Scramjet in various institutes and universities. It summarizes a progress overview of three types of the solid-fueled Scramjet, which covers a wealth of landmark numerical and experimental results. Based on this, several relevant key technologies are proposed. Several inherent scientific issues are refined, such as the mixing mechanism of multi-phase flow and supersonic airflow, ignition and combustion mechanism of the condensed phase in a supersonic airflow, and coupling mechanism of gas and solid phase in a supersonic flow. Finally, the historical development trend is clarified, and some recommendations are provided for future solid-fueled Scramjet.