Large Eddy Simulation of a Film Cooling Flow Injected from an Inclined Discrete Cylindrical Hole into a Crossflow with Zero-Pressure Gradient Turbulent Boundary Layer

A Large Eddy Simulation (LES) is performed of a high blowing ratio (M = 1.7) film cooling flow with density ratio of unity. Mean results are compared with experimental data to show the degree of fidelity achieved in the simulation. While the trends in the LES prediction are a noticeable improvement over Reynolds-Averaged Navier-Stokes (RANS) predictions, there is still a lack a spreading on the underside of the lifted jet. This is likely due to the inability of the LES to capture the full range of influential eddies on the underside of the jet due to their smaller structure. The unsteady structures in the turbulent coolant jet are also explored and related to turbulent mixing characteristic

Fundamental and Applied Experimental Investigations of Corrosion of Steel by LBE under Controlled Conditions: Kinetics, Chemistry Morphology, and Surface Preparation

Advanced nuclear processes such as the transmutation of nuclear waste, fast reactors, liquid-metal-cooled reactors, and spallation neutron sources require advanced materials systems to contain them. The required structural materials must be stable in the presence of nonmoderating coolants. A prime candidate for such a coolant is Lead Bismuth Eutectic (LBE). Materials in these systems must be able to tolerate high neutron fluxes, high temperatures, and chemical corrosion. Unfortunately, LBE corrodes stainless steel. The corrosive behaviors of structural materials in LBE are not well understood. The Russians have over 80 reactor-years experience with LBE coolant in their Alpha-class submarine reactors. The Russians found that the presence of small amounts of oxygen in the LBE significantly reduced corrosion, but a fundamental understanding is incomplete. The formation and breakdown of protective (or non-protective) oxide layers in a steel/LBE is a key materials question

Fundamental and applied experimental investigations of corrosion of steel by LBE under controlled conditions: kinetics, chemistry, morphology, and surface preparation: quarterly report (January 2005-April 2005)

This project has four components: The fabrication of a materials test apparatus with unique capabilities, Comparative studies of steel corrosion under gas phase conditions comparable to the Lead Bismuth Eutectic (LBE) oxygen control conditions, Isotope labeling studies, and Collaborative efforts with other workers in the field. Summary of accomplishments: Started occupation of the High Temperature Materials Experimental Facility. Presented a paper at the meeting of the American Chemical Society in San Diego in March 13-17. Currently reviving the ion beam for implantation experiments. Currently analyzing 38 steel samples from the DELTA loop from LANL

Fundamental and applied experimental investigations of corrosion of steel by LBE under controlled conditions: kinetics, chemistry, morphology, and surface preparation

An innovative research program is proposed to investigate the corrosion of steel by lead alloys, and in particular lead-bismuth eutectic (LBE). In our previous work, some steels were found to be far more resistant to corrosion by LBE than others depending on surface preparation (cold working). This program would allow testing of crucial hypotheses about the causes of the observed increased corrosion resistance. We propose to build a new test facility at UNLV to expose steel samples to LBE as well as facilities to prepare steel samples as indicated by our work. The unique capabilities of the test system will make investigations of the fundamentals of lead alloy corrosion under a variety of conditions feasible and lead to the establishment of new protocols for the minimization of molten lead alloy corrosion of structural materials. These capabilities include fast and controlled sample introduction via a vacuum load lock system, both high temperature operation and controlled chemical environment by the use of alumina and silica or other refractory materials for lead alloy containment, and highly modifiable flow systems for determination of fundamental kinetics and parameters and thus accurate modeling of lead alloy systems. In parallel with the test effort we will prepare well characterized samples of candidate materials and model systems. In particular we shall look at modifications of the sample surface and near surface composition (e.g. the effects of cold working). In addition we shall investigate the feasibility of using the mass selected ion facility at UNLV developed by Prof. Farley to both modify surface composition (e.g. ion implant oxygen to compensate for oxygen deficiencies) of test samples and to introduce stable isotope labels into known steels to determine mass transport properties inside the steels

Experimental investigation of steel corrosion in Lead Bismuth Eutectic (LBE): characterization, species identification, and chemical reactions

The goal of the present research is to achieve a basic understanding of corrosion of steels by Lead Bismuth Eutectic (LBE). Liquid LBE is under consideration in the transmuter as both a spallation target and as a blanket coolant. There have been previous studies of LBE, especially by the Russians, who have over 80 reactor-years experience with LBE coolant in their Alpha-class submarine reactors. However, a fundamental understanding and verification of its role in the corrosion of steels is still very incomplete. We have begun a program of post-experiment testing and analysis on steel samples that have been in intimate contact with LBE. We have employed surface analysis techniques, including Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray (EDAX) spectroscopy, and X-ray Photoelectron Spectrometry (XPS). These techniques, applied to the steel surface, have probed the surface morphology, elemental analysis and oxidation states as a function of position. The measurements were made using the facilities at UNLV. Chemical alterations and resulting chemical species are studied at the steel surface. We plan to use micro-Raman and powder X-ray diffraction in the near future. In addition to these well-established laboratory-based instrumentation approaches at UNLV, we have begun to use a state-of-the-art synchrotron-based spectroscopy and microscopy technique, the X-ray fluorescence microprobe at the Advanced Light Source, at Lawrence Berkeley National Laboratory. We have begun to characterize spectroscopically both the LBE and the stainless steel before and after they interact to determine their composition, including minor components such as chromium and nickel. The proposed research moves toward establishing a rigorous experimental database of experimental measurements of LBE and its reactions with steels. Such a database can be used by DOE scientists and engineers in engineering efforts to control, avoid, and/or minimize the effect of corrosion of steels by LBE, under conditions appropriate to the transmuter