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Computational modeling and analysis of a flow in a storage room

Description: When a radioactive material gas is accidentally released with a room, the present of the hazardous gas will directly affect the people safety inside. In this study, the flow field and gas dispersion in a ventilated tritium storage room at Los Alamos National Laboratory was simulated using CFX-5.5, a commercially available CFD package using a finite volume methodology. CFD models provide a simultaneously numerical solution of continuity, Navier-Stokes, and energy equations for a flow field geometry with specified boundary conditions. CFX-5 uses a coupled solver, which solves the hydrodynamic equations (for u, v, w, p) as a single system. This reduces the number of iterations required for convergence to a steady state, and to a transient analysis solution for each time step in time-dependant gas dispersion as well.
Date: January 1, 2002
Creator: Chen, Z. (Zukun); Konecni, S. (Snezana) & Whicker, J. J. (Jeffrey J.)
Partner: UNT Libraries Government Documents Department

Computational modeling and analysis of airflow in a tritium storage room

Description: In this study, a commercial computational fluid dynamics (CFD) code, CFX-5.5, was utilized to assess flow field characteristics, and to simulate tritium gas releases and subsequent transport in a storage room in the tritium handling facility at Los Alamos. This study was done with mesh refinement and results compared. The results show a complex, ventilation-induced flow field with vortices, velocity gradients, and stagnant air pockets. This paper also explains the timedependent gas dispersion results. The numerical analysis method used in this study provides important information that is possible to be validated with an experimental technique of aerosol tracer measurement method frequently used at Los Alamos. Application of CFD can have a favorable impact on the design of ventilation systems and worker safety with consideration to facility costs.
Date: January 1, 2003
Creator: Chen, Z. (Zukun); Konecni, S. (Snezana) & Whicker, J. J. (Jeffrey J.)
Partner: UNT Libraries Government Documents Department

Computational modeling and experimental characterization of indoor aerosol transport

Description: When a hazardous aerosol or gas is inadvertently or deliberately released in an occupied facility, the airborne material presents a hazard to people. Inadvertent accidents and exposures continue to occur in Los Alamos and other nuclear facilities despite state-of-art engineering and administrative controls, and heightened diligence. Despite the obvious need in occupational settings and for homeland defense, the body of research in hazardous aerosol dispersion and control in large, complex, ventilated enclosures is extremely limited. The science governing generation, transport, inhalation, and detection of airborne hazards is lacking and must be developed to where it can be used by engineers or safety professionals in the prediction of worker exposure, in the prevention of accidents, or in the mitigation of terrorist actions. In this study, a commercial computational fluid dynamics (CFD) code, CFX5.4, and experiments were used to assess flow field characteristics, and to investigate aerosol release and transport in a large, ventilated workroom in a facility at Savannah River Site. Steady state CFD results illustrating a complex, ventilation-induced, flow field with vortices, velocity gradients, and quiet zones are presented, as are time-dependent CFD and experimental aerosol dispersion results. The comparison of response times between CFD and experimental results was favorable. It is believed that future applications of CFD and experiments can have a favorable impact on the design of ventilation (HVAC) systems and worker safety with consideration to facility costs. Ultimately, statistical methods will be used in conjunction with CFD calculations to determine the optimal number and location of detectors, as well as optimal egress routes in event of a release.
Date: January 1, 2002
Creator: Konecni, S. (Snezana); Whicker, J. J. (Jeffrey J.) & Martin, R. A. (Richard A.)
Partner: UNT Libraries Government Documents Department