Numerical and Experimental Investigation of Detonation Initiation in Profiled Tubes

Abstract

Detonation initiation in a tube with parabolic contraction and conical expansion was investigated numerically and experimentally. The optimized geometry of conical expansion with sine-shaped wall is proposed. The generalized diagram in the form of detonation curves at the contraction slope angle versus incident shock Mach number plane is presented. For solving the governing Euler equations, the numerical method based on finite volume approach with Godunov flux approximation adapted for multiprocessor systems is used. It has been shown experimentally that the parabolic contraction and conical expansion ensure shock-to-detonation transition in a stoichiometric propane-air mixture under normal conditions at a very low minimal incident shock wave velocity of 680 ± 20 m/s, which approximately corresponds to a Mach number of 2. This result is important for novel jet propulsion systems with detonative burning of fuel-pulse detonation engines.

Keywords:

• Detonation initiation
• Experiment
• Numerical modeling
• Pulse detonation engine

ACKNOWLEDGMENTS

This work was supported by Russian Foundation for Basic Research (grant 08–08-00068) and Special Purpose Program of Russian Federation, Scientific and Educational Human Resources of Innovative Russia (contracts P359 and P502).