Aim Direct impulse measurement for DDT initiation Calculate

Aim Direct impulse measurement for DDT initiation. Calculate impulse from • Ballistic pendulum • Pressure traces • Wave reflection analysis • Numerical simulation 2 -10 -00 California Institute of Technology Graduate Aeronautical Laboratories

Ballistic pendulum Pendulum: l = 1. 55 m M = 12. 8 kg Tube: L = 1. 5 m I. D = 38 mm Diagnostics: 3 pressure gauges blast gauge video 2 -10 -00 California Institute of Technology Graduate Aeronautical Laboratories

Wave reflection analysis where 2 -10 -00 California Institute of Technology Graduate Aeronautical Laboratories

Pressure integration 2 -10 -00 California Institute of Technology Graduate Aeronautical Laboratories

Preliminary results: Impulse with varying initial pressure (Zitoun R. , Gamezo V. , and Desbordes D. , presented at 2 nd International Meeting: Properties of Reactive Fluids and their Applications to Propulsion. LCD, UPR 9028 CNRS, ENSMA, Futuroscope, March 1996) 2 -10 -00 California Institute of Technology Graduate Aeronautical Laboratories

Preliminary results: Impulse with varying equivalence ratio 2 -10 -00 California Institute of Technology Graduate Aeronautical Laboratories

Conclusions • The problem of determining the impulse delivered by a DDT initiated detonation is being studied in several ways (experimental, theoretical and numerical). • A parametric expression for the impulse based on an analysis of the gas dynamics is being investigated. • A systematic error occurs between impulse measurements made from the ballistic pendulum and pressure history integration. Effects of: Distance to P 1 DDT transition time Other losses experienced by the flow Future Work • Investigation of exit geometry. • Investigation of the effectiveness of initiation processes. 2 -10 -00 California Institute of Technology Graduate Aeronautical Laboratories