Effects of Finite Density Fluctuations and of the Upper Hybrid Resonance on O-X Correlation Reflectometry (open access)

Effects of Finite Density Fluctuations and of the Upper Hybrid Resonance on O-X Correlation Reflectometry

The correlation between O-mode and X-mode reflectometer signals is studied with a 1-D reflectometer model taking into account the influence of finite density fluctuation levels and the upper hybrid resonance. It is found that a high level of O-X correlation can only be achieved for sufficiently small density fluctuation levels (typically much less than 1%) or very low magnetic field strengths. The influence of the upper hybrid resonance on the O-X correlation was found to also degrade the correlation between the O and X mode signals for very low magnetic field strengths or for very short density scale lengths. The extrapolation of these results to reactor-scale parameters indicates that the magnetic field strength can reliably be measured in the core plasma provided the density fluctuation level is typically much less than 1%.
Date: February 10, 2001
Creator: Kramer, G. J.; Nazikian, R. & Valeo, E.
Object Type: Report
System: The UNT Digital Library
Tracer Mixing at Fracture Intersections (open access)

Tracer Mixing at Fracture Intersections

Discrete network models are one of the approaches used to simulate a dissolved contaminant, which is usually represented as a tracer in modeling studies, in fractured rocks. The discrete models include large numbers of individual fractures within the network structure, with flow and transport described on the scale of an individual fracture. Numerical simulations for the mixing characteristics and transfer probabilities of a tracer through a fracture intersection are performed for this study. A random-walk, particle-tracking model is applied to simulate tracer transport in fracture intersections by moving particles through space using individual advective and diffusive steps. The simulation results are compared with existing numerical and analytical solutions for a continuous intersection over a wide range of Peclet numbers. This study attempts to characterize the relative concentration at the outflow branches for a continuous intersection with different flow fields. The simulation results demonstrate that the mixing characteristics at the fracture intersections are a function not only of the Peclet number but also of the flow field pattern.
Date: February 10, 2001
Creator: Li, Guomin
Object Type: Article
System: The UNT Digital Library
MINIMIZATION OF CARBON LOSS IN COAL REBURNING (open access)

MINIMIZATION OF CARBON LOSS IN COAL REBURNING

This project develops Fuel-Flexible Reburning (FFR), which combines conventional reburning and Advanced Reburning (AR) technologies with an innovative method of delivering coal as the reburning fuel. The overall objective of this project is to develop engineering and scientific information and know-how needed to improve the cost of reburning via increased efficiency and minimized carbon-in-ash and move the FFR technology to the demonstration and commercialization stage. The first reporting period (August 11, 2000-February 10, 2001) included experimental activities with the primary objective to characterize the impacts of reburning process parameters on NO{sub x} reduction at conditions typical of the full-scale boilers. Tests were conducted in GE EER's Boiler Simulator Facility (BSF). Tests showed that NO{sub x} reduction in basic coal reburning depends on process conditions, initial NO{sub x} and coal type. Up to 60% NO{sub x} reduction was achieved at optimized conditions.
Date: February 10, 2001
Creator: Zamansky, Vladimir M. & Lissianski, Vitali V.
Object Type: Report
System: The UNT Digital Library