2/10/00California Institute of Technology Graduate Aeronautical Laboratories 1 Detonation Research for Propulsion Applications Sponsored by ONR MURI “Multidisciplinary Study of Pulse Detonation Engines” PSU/CIT/Princeton Team J. E. Shepherd, E. Schultz, J. Austin, T. Chao, E. Wintenberger, P. Hung Graduate Aeronautical Laboratories California Institute of Technology Pasadena, CA USA Midyear Review, San Jose, CA, February 10-11, 2000

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 2 Activities at Caltech Cellular structure characterization Initiation Diffraction Structural and thermal response

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 3 Cellular Structure Purpose: characterize detonations in JP-5, JP-8, JP-10 fuels (  measurement 

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 4 CIT 288-mm Detonation Tube Tube modifcations: 1. Redesigned using FEM 2. Stronger flange-tube connections 3. Thicker flanges 4. Double number of fasteners 5. Heating system a) 8 zones of control b) 10 kW total power 6. Higher temperature seals

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 5 Detonation initiation DDT time scale analysis Ideal vs real performance with DDT

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 6 DDT Scaling

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 7 Ideal PDE Impulse Computation by H. Hornung using Amrita (AMR) q/RT 1 = 40,  = 1.2 Taylor-Zeldovich IC

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 8 Diffraction Test series with H2, C2H4, C3H8 fuels –Ar, He, N2, CO2 dilution. –Model development

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 9 Structural response Response of tube to detonation loading

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 10 CIT Presentations Structural response (Joe Shepherd) Diffraction (Eric Schultz) DDT and ideal performance (Jo Austin)

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 11 Progress to Date 288-mm tube modifications started –mechanical changes done Diffraction study in 38-mm tube done –kinetics validation, model development Preliminary DDT time scale study Impulse, P(t) measurements initiated 2D transient FEM studies

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 12 Structural Response of Detonation Tubes J. E. Shepherd, T. Chao, P. Hung - GALCIT

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 13 Goals Modeling of thermo-elastic response of tubes to detonation loading 3D FEM computations with imposed detonation or shock loading Develop design criteria Experiments to examine failure mechanisms and thresholds

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 14 Flexural Wave Excitation Traveling loads (shock or detonation) excite flexural waves in tubes Resonance associated with waves traveling at flexural wave speed Deformations can be up to 4X static equivalent

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 15 Flexural Wave Excitation 1.5 mm thick steel tube, 25 mm  0.5 m long Critical velocity 927 m/s, shock speed 950 m/s 2D Axi-symmetric explicit FEM

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 16 Loading by Flexural Waves Experiments in Caltech 288-mm detonation tube Amplification factor U (m/s) Measured strain (hoop) t (ms)

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 17 Future Directions More realistic tube configuration Use gas dynamic simulations to provide boundary conditions Investigation of stress concentrations Coupling to thermal effects Comparison with measurements in model tubes

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 18 Schedule I

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 19 Schedule II

2/10/00California Institute of Technology Graduate Aeronautical Laboratories 20 Schedule III