Short Summary Showing Only Employers & Employment Periods
Work associated with ASC (Advanced Simulation and Computing) software and application projects.
Chief Scientist in X-4 (nuclear &
hydrodynamic applications) in Applied Physics Division
Primary Burn Verification & Validation Milestone Project Leader.
Work associated with ASC (Advanced Simulation and Computing) projects.
Work associated with various U.S. infrastructure analysis, such as electrical power grid, natural gas delivery, and transportation. These were extremely large coupled nonlinear systems with both weakly and tightly coupled behavior.
Past work at Los Alamos included work on the Transient Reactor Analysis Code (TRAC) involving Mods 1, 2, and 3. Within these time periods, TRAC was the advanced code used to address nuclear reactor safety issues by the US Nuclear Regulatory Commision (NRC). Mod2 represents the NRC's latest best-estimate 3-dimensional code while Mod3 relates to DOE heavy-water reactors. My responsibilities included development of the closure packages (wall and interfacial heat transfer and wall and interfacial drag) and their numerical coupling into the code. Principal efforts have been the development of a new reflood package (see recent awards) for the Mod2 code and a radiation heat transfer model for Mod3.
Job responsibilities included development of extended modeling capabilities for the quenching of structures with liquid being introduced from either the top or bottom. The application of this work is the analysis of potential accidents for the Westinghouse AP600 reactor design. New methodology was developed with this task due to the complex coupled nature of the phenomena and the multidimensionality. This methodology uses nonlinear optimization as a part of the model development process. Responsibilities have also included the next generation thermal-hydraulics code structured for the vector/parallel architecture of the CRAY's and future supercomputers. Funding for these two efforts was about $1M each. I was principally responsible for obtaining that funding associated with the first and shared equally with another staff member in the second.
My work also included study of the basic mechanisms in the boiling process sponsored by Los Alamos National Laboratory. Emphasis of this research included the influence of heater materials and their thickness on both nucleate boiling and the critical heat flux. The nonlinear on-off behavior of possible nucleation sites has been studied and shown to exhibit potential chaotic behavior. This leads, I believe, to identification of the underlying controlling principle for boiling. This work has been done with three different post-doctoral fellows sponsored by Los Alamos.
Taught graduate courses in convection and radiation heat transfer and two-phase thermal-hydraulics.
Major area of interest with the Loss-of Fluid Test (LOFT) program was heat transfer with emphasis on post-CHF boiling. From this work, I proposed a theory of how quenching occurs and developed an experimental program to help quantify the theory. I also developed a unified CHF theory and a probe to measure liquid-contact times in post-CHF boiling. These last two developments were cooperative efforts with Professors Gunnerson (now at University of Idaho) and Chen (Lehigh University), respectively.
Other work areas included the RELAP5 thermal-hydraulics code, modeling of LOFT's external fuel rod thermocouple, and several LOFT-related heat transfer problems. For example, study of predicted and experimental differences for small-break transient L9-1/L3-3 revealed major modeling deficiencies. That explanation saved repeating the experiment at a cost of $1M.
Work involved code development of RELAP4, a computer code used in the prediction of thermal-hydraulic system transients. Assignments included modeling of fuel pins, radiation and convection heat transfer, reactor core hydraulics, core thermal nonequilibrium, and steam generators. Other projects included work with the RELAP5 heat transfer and consultation with the LOFT and Power Burst Facility experimental programs.
Work involved two areas: the design and development of new products, and work with Gould's MK-48 torpedo production. The major design project was the MK-46 torpedo NEARTIP acoustic transducer. Responsibilities included design of the transducer element and minimization of the transducer's self-noise limit. Transducer element design involved the use of optimization techniques and computer simulations to meet both the operational and design constraints. Limitation of the self noise required design of a series of experiments to identify the cause of the self noise. MK-48 production work involved computer simulation and statistical sampling techniques to study the tractability of transducers in the high-volume production environment. Major results of the program were development of (1) improved production procedures to increase the reliability of the transducers; (2) a new quick and accurate technique to measure the extensional velocity of sound in components; (3) computer simulation and sampling techniques to study the effects of transducer component material properties, dimensions, and their tolerances upon the transducers produced from them.
Other responsibilities included a six-month management training period, during which I was assistant manager of the department. I also served as consultant to other divisions on various vibrational, stress analysis, and acoustical problems.
Responsible for various research and development programs. These involved the design of improved composite longitudinal low-frequency sonar transducers and their isolation from vibration and shock. Also involved the measurement of acoustical properties of sonar transducer materials and pressure release materials.