Numerical simulations of free-surface flows of a Carbopol solution
Abstract not provided.
Publications
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Jump to search filtersComputational models and experimental studies of mold filling in thin channels with yield stress fluids
Abstract not provided.
Polyurethane Foam Manufacturing Models Using a FEM‐Level Set‐Population Balance Approach
Abstract not provided.
Multiphysics Modeling Of Long-Term Aging And Deformation Mechanisms In Polyurethane Foams
Abstract not provided.
Computational Models for Fluid-to-Solid Transitions in Yield Stress Fluids
Abstract not provided.
Computational Models for Fluid-to-Solid Transitions in Yield Stress Fluids
Abstract not provided.
Computational models and experimental studies of mold filling in thin channels with yield stress fluids
Abstract not provided.
Using Alkaline Carbonate to Mitigate Molten Corium in Severe Nuclear Reactor Accidents
Abstract not provided.
Thermomechanical Behavior of Polyurea Nanocomposites
Abstract not provided.
Computational Models of Polyurethane Foam Formation for Property Prediction
Abstract not provided.
Numerical study of an elastoviscoplastic mold filling experiment
Abstract not provided.
Multiphysics Modeling of Coupled Chemical-Thermal-Mechanical Phenomena in Chemically Blown Polyurethane Foams during Manufacturing & Aging
Abstract not provided.
Multiphysics Modeling Of Long-Term Aging And Deformation Mechanisms In Polyurethane Foams
Abstract not provided.
Computational models for fluid-to-solid transitions in yield stress fluids
Abstract not provided.
Computational models for fluid-to-solid transitions in yield stress fluids (flash version)
Abstract not provided.
Bubble-size Experiments and Predictions for Polyurethane Foam using a Population Balance Equation
Abstract not provided.
Local Arrest of Carbopol Gel in a Quasi Two-Dimensional Flow
Abstract not provided.
Polyurethane foam process models using a population balance method
Abstract not provided.
Goma History and Capabilities Seminar
Abstract not provided.
Material Models for Polyurethane Foam Encapsulation and Aging
Abstract not provided.
Using Alkaline Carbonate to Mitigate Molten Corium in Severe Nuclear Reactor Accidents
Abstract not provided.
Foam process models for polyurethane including blowing and curing kinetics
Abstract not provided.
Using Alkaline Carbonate to Mitigate Molten Corium in Severe Nuclear Reactor Accidents
Abstract not provided.
Diagnostics and Models for Birthing Stress
Understanding the stress development in fluids as they transition to solids is not well-understood. Computational models are needed to represent "birthing stress" for multiphysics applications such as polymer encapsulation around sensitive electronics and additive manufacturing where these stresses can lead to defects such as cracking and voids. The local stress state is also critical to understand and predict the net shape of parts formed in the liquid phase. In this one-year exploratory LDRD, we have worked towards a novel experimental diagnostic to measure the fluid rheology, degree of solidification, and the solid stress development simultaneously. We debugged and made viable a "first-generation" Rheo-Raman system and used it to characterize two types of solidifying systems: paraffin wax, which crystalizes as it solidifies, and thermoset polymers, which form a network of covalent bonds. We used the paraffin wax as a model system to perform flow visualization studies and did some preliminary modeling of the experiment, to demonstrate the inadequacy of the current modeling approaches. This work will inform an advanced fluid constitutive equation that includes a yield stress, temperature dependence, and an evolving viscosity when we pursue the full proposal, which was funded for FY20.
A New Method to Contain Molten Corium in Catastrophic Nuclear Reactor Accidents
The catastrophic nuclear reactor accident at Fukushima damaged public confidence in nuclear energy and a demand for new engineered safety features that could mitigate or prevent radiation releases to the environment in the future. We have developed a novel use of sacrificial material (SM) to prevent the molten corium from breaching containment during accidents as well as a validated, novel, high-fidelity modeling capability to design and optimize the proposed concept. Some new reactor designs employ a core catcher and a SM, such as ceramic or concrete, to slow the molten corium and avoid the breach of the containment. However, existing reactors cannot easily be modified to include these SMs but could be modified to allow injectable cooling materials (current designs are limited to water). The SM proposed in this Laboratory Development Research and Development (LDRD) project is based on granular carbonate minerals that can be used in existing light water reactor plants. This new SM will induce an endothermic reaction to quickly freeze the corium in place, with minimal hydrogen explosion and maximum radionuclide retention. Because corium spreading is a complex process strongly influenced by coupled chemical reactions (with underlying containment material and especially with the proposed SM), decay heat and phase change. No existing tool is available for modeling such a complex process. This LDRD project focused on two research areas: experiments to demonstrate the feasibility of the novel SM concept, and modeling activities to determine the potential applications of the concept to actual nuclear plants. We have demonstrated small-scale to large-scaled experiments using lead oxide (Pb0) as surrogate for molten corium, which showed that the reaction of the SM with molten Pb0 results in a fast solidification of the melt and the formation of open pore structures in the solidified Pb0 because of CO2 released from the carbonate decomposition.
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