Analytic Model for Single-Cycle Detonation Tube with Diverging Nozzles

摘要

An analytic model for quantifying the specific impulse of a single-cycle detonation tube fitted with a diverging nozzle is developed. The model takes advantage of the fact that the detonation tube is choked, thus enabling the straight-tube and nozzle impulses to be dealt with separately. No assumptions of steady flow are needed, and the model can be applied even for nozzles that are not pressure-matched to the environment The model is validated against ballistic-pendulum measurements. Application of the model is demonstrated by identifying optimized area ratios over a wide range of pressures. The optimized area ratio is shown to be mainly a function of the ambient/ plateau pressure ratio P_∞/P_3.