Hugoniot Relation for a Bow-Shaped Detonation Wave Generated in RP Laser Propulsion

Repetitive-pulsed (RP) laser propulsion is expected to replace chemical propulsion systems because it can reduce launch costs. A laser-supported detonation wave (LSD) plays an important role in the thrust-generation process of RP laser propulsion. The LSD propagation mechanism has been studied. Nevertheless, the LSD propagation velocity measured in an earlier study was lower than the Chapman-Jouguet (CJ) velocity, which meant that Hugoniot analysis produced no solution. The findings suggest that the radial flow from the central axis of LSD exerts some effects, but it has not been evaluated quantitatively. Two-dimensional axisymmetric computational fluid dynamics (CFD) analysis using the measured propagation velocity was performed for this study to evaluate effects of the radial flow of a bow-shaped LSD. Results show that the ratios of the radial flow of mass, momentum, and enthalpy from the central axis can be calculated, respectively, as 0.82, 0.13, and 0.17. Additionally, the measured propagation velocity of a bow-shaped LSD was shown to be higher than the CJ velocity calculated using the two-dimensional axisymmetric CFD reproducing the experiment conditions.

Automated summary

Repetitive-pulsed (RP) laser propulsion technology has the potential to reduce launch costs and replace chemical propulsion systems. The role of laser-supported detonation wave (LSD) in RP laser propulsion has been studied, but the mechanism of LSD propagation remains unclear. In this study, two-dimensional axisymmetric computational fluid dynamics (CFD) analysis was conducted to evaluate the effects of radial flow in a bow-shaped LSD, and the measured propagation velocity was found to be higher than the Chapman-Jouguet (CJ) velocity.