Numerical study on impulse characteristics of laser-supported air-breathing pulsed detonation thrusters

Abstract

A laser-supported air-breathing thruster utilizes the remote laser energy and atmospheric air to boost a vehicle. To calculate the impulse induced by a laser pulse, the operational process was divided into two phases. First, one dimension (1D) laser-supported absorption waves in the air were simulated by an implicit dual-time method, and laser absorption efficiencies were predicted, based on a more accurate absorption model and three temperatures thermal nonequilibrium. Sequentially, impulses for different parabolic thrusters and pulse energies were computed, considering the high-temperature real gas effect. Then experiments were conducted with a ballistic pendulum apparatus. The calculations of 1D absorption waves show that as laser intensity increases, the electron number density would reach the critical value, resulting in a laser reflection and decrease of absorption efficiency. Further calculations for thrusters imply the thrust oscillation due to air-refilling has an evident influence on the total impulse received, and because of a higher thrust peak and longer positive phase time, the flat top and longer configuration would significantly enhance the performance. Experimental results show that the errors of the impulse calculations for two thrusters are 4.2% and 9.4%, respectively, which verifies the calculation model.