Thrust Demonstration of a Pulse Detonation Rocket "TODOROKI"

Abstract

Pulse detonation engine (PDE) can be operated even if there are no compression mechanisms such as compressors and pistons. The rocket engine with an extremely low combustor fill pressure becomes possible (pulse detonation rocket engine, PDRE). In this research, the low pressure propellant (ethylene-oxygen gas at 0.1 MPa) was filled to the combustor, and the PDRE system that increased the specific impulse by a partial filling was modeled. Further, the performance predicted by this model was experimentally confirmed. The thrust can be calculated by using the simplified PDE model of Endo et al. and partial filling effect models of Sato et al. The mass flow rate of the propellant supplied from the pressurized cylinders is considered in this calculation. As a result, the thrust performance can be determined by the kind of propellant, the initial conditions of the gas in the cylinders, and the supply-valve orifice and the PDE-tube volume, and the operation frequencies. We fabricated a pulse detonation rocket (PDR) named “TODOROKI”, and the thrust calculation model was verified by the horizontal sliding test of this PDR. PDR-TODOROKI has all necessary components such as the gas cylinders, electromagnetic valves, a combustor (a PDE tube), and the controller and can slide on the rails independently. PDR-TODOROKI has spring-damper system that relaxes the intermittent impulsive thrust at the end wall of the PDE tube (combustor). We confirmed that the stability of the PDE operation depends on the ratio between the purge-gas thickness and the tube diameter. The thrust predicted by the calculation model was identical to experimental results within 4%.