Preliminary design of a hypersonic airbreathing vehicle based on four steps: An academic approach to learning

This article proposes a systematic approach for the preliminary design of a hypersonic airbreathing (scramjet) vehicle within an academic context. The goal is to serve as an educational tool, focusing on teaching students the fundamental physical concepts behind scramjets. The article provides essential equations for generic scramjet designs while explaining the simplifications made from an academic perspective. It demonstrates the use of spreadsheets as a user-friendly tool to modify parameters and observe the behavior of shock waves. The article outlines a four-step procedure. It includes estimating atmospheric properties, designing the supersonic inlet, calculating combustion chamber parameters, and determining postcombustor properties. An academic exercise illustrates these steps for a scramjet flying at a specific velocity and altitude. The results show that this procedure, combined with spreadsheets, enables a rapid prediction of thermodynamic properties, enhancing the understanding of the fundamental physics behind hypersonic airbreathing vehicles.