Investigation of Solid Fuel Ramjets using Analytical Theory and Computational Fluid Dynamics

This paper investigates the modeling and analysis of a solid-fuel ramjet (SFRJ) using analytical theory and computational fluid dynamics (CFD). The primary objectives of this study are to first apply analytical theories of an SFRJ in combination with combustion physics from NASA CEA software to establish a foundation for analytically modeling the thrust of an SFRJ with a specified bypass ratio. Secondly, this study aims to model the thrust output of an SFRJ using a simplified backward-facing step computational model consisting of a single inlet and outlet through computational analysis. In the computational model, combustion is modeled as wall heat addition, and thermal choking effects leading to engine unstart conditions are predicted. While there are more complex SFRJ modeling approaches, consideration of computational cost is an important aspect of this work, since these models will be coupled with a control system. This research serves as a foundational step in a broader investigation aimed at coupling SFRJ thrust dynamics with control systems for regulating thrust under uncertain operating conditions.