Dr. Craig Tarver, LLNL
Craig Tarver was born in Syracuse, New York and attended Syracuse Central Technical High School. He then attended Clarkson University and graduated with a B.S. in Chemistry in 1968. Next he enrolled at Johns Hopkins University earning a Ph.D in Chemistry in 1973. Craig then joined the SRI International in 1973. In 1976, he joined the Chemistry Department at Lawrence Livermore National Laboratory, where he worked for 45 years before retiring in 2019.
Title: Calculating Overdriven Detonation for Reaction Product Shock States at Pressures Higher than those for Steady Detonation Waves
Abstract: When detonation waves impact high impedance materials, are overdriven in gas gun or laser experiments, enter a converging geometry, etc., shock pressures much higher than steady, Chapman-Jouguet (C-J) detonation can be generated. Such measurements have steadily improved over the past 50 years as spacial and time resolution have improved.1 So has reaction product equation of state modeling. The Jones-Wilkins-Lee (JWL) reaction product equations of state were originally fit only to product expansion below C-J and were too compressible at higher pressures. Urtiew and Hayes2 showed that by raising R1, R2, and ω, they could improve fits to overdriven data, while still matching product expansion data below the C-J state.
In the 1990s, Nellis, Mitchell, et al3 measured high-pressure Hugoniots of dissociating liquid nitrogen, ionization of water, and CO/CO2 equilibrium as functions of shock pressure. The shock temperatures of individual dimers and trimers are higher than those for detonation C-J waves, which distribute their internal energy over more product vibrational modes. Thus more N2 dissociation, more H2O ionization, and different CO2/CO ratios occur in the Nellis experiments compared to detonation. The large dissociation energy of N2 has the greatest effect on the CHEETAH chemical equilibrium calculations, as shown by Tarver1 for HMX and TATB overdriven detonation waves.
- Tarver, C.M., Journal of Physical Chemistry A, 124, 1399 (2020).
- A. Urtiew and B. Hayes, Combustion, Explosion, and Shock Waves 27, 505–514(1991)
- J. Nellis et al. J. Chem. Phys. 94, 2244–2257 (1991)