The Department of Energy in collaboration with the Electric Power Research Institute is in the process of conducting the High Burnup Demonstration Project, where the objective is to characterize the performance of hig...
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(纸本)9780791885352
The Department of Energy in collaboration with the Electric Power Research Institute is in the process of conducting the High Burnup Demonstration Project, where the objective is to characterize the performance of high-burnup fuel in long term storage. As part of this demonstration, a TN-32B dry storage cask was instrumented and loaded with spent nuclear fuel at North Anna Nuclear Generating Station in November 2017. The project cask provides a unique opportunity to gain information on spent fuel and cask performance from an in-service operational system. The cask was instrumented with thermocouples inside of the fuel assemblies, then loaded and dried using normal procedures. After the drying process a thermal soak period where the cask was left indoors was used to obtain steady temperatures for model comparison along with surface temperatures. This paper details thermal modeling validation work that was done to model both the steady state and transient cases. Two modeling tools were used to predict temperatures in the cask. The general purpose cfd and heat transfer code STAR-CCM+ was used with both a detailed pin-by-pin model along with a more efficient k-effective simplification. The other code is COBRA-SFS, a purpose-built detailed thermal modeling tool developed and maintained at PNNL. Results from all the modeling tools were compared blind to the test data. Each model utilized general design information and compared reasonably well to the blind steady state data using convection and surface temperature boundary conditions. Post-test adjustments were later made to better reflect the "as built" conditions of the cask. Based on lessons learned from the steady state analysis the vacuum drying process was modeled in both codes. Utilizing the measured loading conditions the transient models were able to compare very well with the measured data. Overall the project showed an ability to model spent fuel storage conditions very well and future work is planned to general
Kaneko and Fischer (https://***/articles/10.3389/fphy.2022.905392) put forth an augmented-basis method (ABM) to stabilize reduced order models (ROMs) of turbulent incompressible flows. The new strategy augments the cl...
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Kaneko and Fischer (https://***/articles/10.3389/fphy.2022.905392) put forth an augmented-basis method (ABM) to stabilize reduced order models (ROMs) of turbulent incompressible flows. The new strategy augments the classical POD basis functions with divergence-free projections of a subset of the nonlinear interaction terms that constitute a significant fraction of the time-derivative of the solution. The numerical investigation shows that the ABM outperforms the standard ROM and the Leray regularized ROM. Huang et al. (https://***/articles/10.3389/fphy.2022.900064) propose a component-based domain-decomposition framework for the modeling of large-scale systems that cannot be directly accessed using the high-fidelity simulations (e.g., rocket engines or wind farms). The new framework decomposes the full system into different components, each of which can flexibly adopt different modeling strategies (e.g., reduced order modeling or full order modeling), balancing physical complexity with accuracy requirements. The authors investigate the new framework in the numerical simulation of complex flows involving combustion dynamics. Tsai and Fischer (https://***/articles/10.3389/fphy.2022.903169) propose a time-averaged error indicator for regularized ROMs of two-dimensional unsteady natural convection in a high-aspect ratio slot parameterized with the Prandtl number, Rayleigh number, and slot angle with respect to the gravity. The authors show that the Leray-regularized ROMs provide a robust strategy for this class of flows. Chan et al. (https://***/articles/10.3389/fphy.2022.898028) show that, for variable density flows with under-resolved features, there are differences in robustness between entropy stable schemes which incorporate the entropy projection and those which do not. These differences in robustness are observed to depend on the density contrast and persist across a range of polynomial degrees, mesh
Vertical axis wind turbines (VAWT) have a number of advantages over the horizontal axis wind turbines (HAWT), however the performance is a little smaller, so that researches for their development should be continued f...
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Vertical axis wind turbines (VAWT) have a number of advantages over the horizontal axis wind turbines (HAWT), however the performance is a little smaller, so that researches for their development should be continued for the implementation of these turbines in urban environment for electrical energy generation. This paper provides an overview of characterization of the VAWT, through a literature review, making comparisons with the HAWT and highlighting the advantages and disadvantages of this type of turbines. The paper also defines and compares the main exist types of VAWT for application in urban environment, so that aims to be a first step towards development of a VAWT research. Finally, this paper features how the aerodynamic optimization of a VAWT can be obtained defining the experimental and the computational numerical analysis, by the relationship between them.
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