Pulse detonation engine as a ramjet replacement

System-level performance analyses of pulse detonation engines (PDE) have not demonstrated the same increases in performance, when compared to constant-pressure-based engine cycles, as those predicted by thermodynamic cycle analyses. This question is revisited in the present work, in which the performance of a PDE, based on specific impulse, is compared to that of a ramjet Mach 1.2 to 3.5. Using a constant-volume analytical model, event timing, geometric and injection parameters providing optimal performance were determined. These were then used as input to a one-dimensional model, based on the method of characteristics, and a two-dimensional model, based on computational fluid dynamics. The effect of partial fill and nozzle expansion ratio on specific impulse was also evaluated. For all models and over the range of Mach numbers considered, the specific impulse of the PDE was consistently greater than that of a ramjet. In addition, partial fill and nozzle expansion ratio were also identified as important factors influencing performance.