FY06 L2C2 HE program report Zaug et al.
The purpose of this project is to advance the improvement of LLNL thermochemical computational models that form the underlying basis or input for laboratory hydrodynamic simulations. Our general work approach utilizes, by design, tight experimental-theoretical research interactions that allow us to not empirically, but rather more scientifically improve LLNL computational results. The ultimate goal here is to confidently predict through computer models, the performance and safety parameters of currently maintained, modified, and newly designed stockpile systems. To attain our goal we make relevant experimental measurements on candidate detonation products constrained under static high-pressure and temperature conditions. The reduced information from these measurements is then used to construct analytical forms that describe the potential surface (repulsive energy as a function of interatomic separation distance) of single and mixed fluid or detonation product species. These potential surface shapes are also constructed using input from well-trusted shock wave physics and assorted thermodynamic data available in the open literature. Our potential surfaces permit one to determine the equations of state (P,V,T), the equilibrium chemistry, phase, and chemical interactions of detonation products under a very wide range of extreme pressure temperature conditions. Using our foundation of experimentally refined potential surfaces we are in a position to calculate, with confidence, the energetic output and chemical speciation occurring from a specific combustion and/or detonation reaction. The thermochemical model we developed and use for calculating the equilibrium chemistry, kinetics, and energy from ultrafast processes is named 'Cheetah'. Computational results from our Cheetah code are coupled to laboratory ALE3D hydrodynamic simulation codes where the complete response behavior of an existing or proposed system is ultimately predicted. The Cheetah thermochemical code is also used by well over 500 U.S. government DoD and DOE community users who calculate the chemical properties of detonated high explosives, propellants, and pyrotechnics. To satisfy the growing needs of LLNL and the general user community we continue to improve the robustness of our Cheetah code. The P-T range of current speed of sound experiments will soon be extended by a factor of four and our recently developed technological advancements permit us to, for the first time, study any chemical specie or fluid mixture. New experiments will focus on determining the miscibility or coexistence curves of detonation product mixtures. Our newly constructed ultrafast laser diagnostics will permit us to determine what chemical species exist under conditions approaching Chapman-Jouguet (CJ) detonation states. Furthermore we will measure the time evolution of candidate species and use our chemical kinetics data to develop new and validate existing rate laws employed in future versions of our Cheetah thermochemical code.
|Creator/Author:||Zaug, J M ; Crowhurst, J C ; Howard, W M ; Fried, L E ; Glaesemann, K R ; Bastea, S|
|Publication Date:||2008 Aug 01|
|OSTI Identifier:||OSTI ID: 945717|
|DOE Contract Number:||W-7405-ENG-48|
|Other Number(s):||TRN: US200904%%128|
|Resource Type:||Technical Report|
|Research Org:||Lawrence Livermore National Laboratory (LLNL), Livermore, CA|
|Subject:||37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; CHEMICAL EXPLOSIVES; CHEMICAL PROPERTIES; CHEMISTRY; COMBUSTION; COMPUTERS; EQUATIONS OF STATE; EXPLOSIONS; HYDRODYNAMICS; KINETICS; LASERS; MIXTURES; PHYSICS; SAFETY; SHOCK WAVES; SOLUBILITY; STOCKPILES; THERMODYNAMICS; VELOCITY|
|Country of Publication:||United States|
|Format:||Size: PDF-file: 73 pages; size: 13.8 Mbytes|
|Update Date:||2009 Mar 09|