November 15, 2011 | News
The CUNY Energy Institute is proud to announce that we have been awarded two prestigious grants from the Department of Energy’s Nuclear Energy University Programs (NEUP). The goal of NEUP is to support the growth of nuclear engineering and science research and education at the university and college level. NEUP has funded more than $80 million in research projects since the 2009 fiscal year. We greatly appreciate this significant support. These grants will help expand the nuclear engineering research and education we can provide at the City College of New York (CCNY) campus. Started in 2009, City College offers the only nuclear engineering program in the tri-state area.
Below are the research and development abstracts for the grants we received:
Experimental Investigation of Convection and Heat Transfer in the Reactor Core for a VHTR
PI: Masahiro Kawaji – City College of New York
Collaborators: Sanjoy Banerjee – CCNY
Manohar S. Sohal – INL, Richard R. Schultz – INL, Hans Gouger – INL
Budget: $1,118,856 over 3 years
This project aims at identifying and characterizing the conditions under which abnormal heat transfer phenomena would occur in Very High Temperature Reactors (VHTR). High pressure high temperature experiments will be conducted to obtain data that would be used for validation of VHTR design and safety analysis codes. As shown in several Phenomena Identification and Ranking Tables (PIRT) for VHTRs under normal steady-state, transient, and accident scenarios, the key phenomena leading to localized hot spots in the reactor core include degraded heat transfer in coolant channels, laminarization of flow, effects of bypass flow and non-uniform heat generation across the core. These phenomena will be investigated using a unique high pressure, high temperature facility recently constructed at the University. The focus of these experiments will be to generate benchmark data for design and off-design heat transfer for forced, mixed and natural convection in a VHTR core with prismatic blocks.
A key research area related to the VHTR is the development of a best estimate capability to predict coupled convection-radiation heat transfer and calculate the presence of hot spots in the core. This is particularly true given that the bypass flow in a prismatic reactor core may change by as much as a factor of six during the lifetime of the reactor. Hence it is essential to be able to identify and calculate the flow behavior in the core cooling channels and bypass gaps during both operational and accident conditions. To this end, Nuclear Regulatory Commission is modifying or enhancing legacy analysis tools but they either ignore or approximate fundamental physics for both prismatic and pebble bed helium gas cooled reactor cores. Therefore, the main objective of this proposal is to develop reliable thermal-hydraulic data for the development of VHTR design codes and safety analysis codes in coordination with other DOE projects underway or being planned within the Next Generation Nuclear Plant (NGNP) experimental verification & validation (V&V) program.
Development of an Efficient Meso-scale Multi-phase Flow Solver in Nuclear Applications
PI: Taehun Lee – City College of New York (CCNY)
Collaborators: Sanjoy Banerjee – CCNY, Masahiro Kawaji – CCNY
Kent E. Wardle – Argonne National Laboratory
Budget: $505,858 over 3 years
The proposed research aims at formulating a predictive high-order Lattice Boltzmann Equation for multi-phase flows relevant to nuclear energy related applications—namely, saturated and sub-cooled boiling in reactors, and liquid-liquid mixing and extraction for fuel cycle separation. An efficient flow solver will be developed based on the Finite Element based Lattice Boltzmann Method (FE-LBM), accounting for phase-change heat transfer and capable of treating multiple phases over length scales from the submicron to the meter. LBM is a mesoscale approach, which can accommodate coarse-grained, molecular-level information into the macroscopic description of complex interfacial phenomena. This is achieved by introducing a phase field function into a single-phase lattice Boltzmann formulation to distinguish between phases (i.e. liquid-vapor or liquid-liquid), together with a phenomenological free energy functional of the solid-liquid-vapor system whose dissipative minimization constrains the temporal evolution of the phase field. The proposed FE-LBM will provide stability and geometric flexibility while retaining the original LBM’s high accuracy and scalability in massively parallel computing platforms.
A thermal LBM will be developed in order to handle adjustable Prandtl number, arbitrary specific heat ratio, a wide range of temperature variations, better numerical stability during liquid-vapor phase change, and full thermo-hydrodynamic consistency. Recent advances in multiphase LBM methodology have also demonstrated the potential for extension of LBM beyond two phases. We propose to extend FE-LBM to liquid–liquid–gas multi-phase flows for application to high-fidelity simulations building up from the meso-scale up to the equipment sub-component scale. While several relevant applications exist, the initial applications for demonstration of the efficient methods to be developed as part of this project include numerical investigations of Critical Heat Flux (CHF) phenomena in nuclear reactor fuel bundles, and liquid-liquid mixing and interfacial area generation for liquid-liquid separations. Large Eddy Simulation (LES) based on the dynamic global-coefficient model for multi-phase flows will be carried out. In addition, targeted experiments will be conducted for validation of these advanced multi-phase models.