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CFD analysis of mine face ventilation systems.
Wala AM; Jacob JD; Huang G
NIOSH 2005 Jan; :1-80
The use of extended (deep) cut mining with remotely controlled continuous miners is commonly utilized across the, U.S. coal industry. Operators adopt this method to maximize the productivity of their continuous miner sections. The accompanying higher advance rates introduce the problem that higher levels of methane are liberated at the face during coal extraction. This requires an increase in the air supply to the face of the heading for adequate methane dilution. Higher air velocities are a consequence, which, in turn, lead to the entrainment of more dust generated during the coal extraction procedure. Frequently, the increased dust entrainment is countered by the use of large capacity scrubbers that recirculate and filter air in the immediate face area. These circumstances give rise to many concerns concerning miners' health and safety. The former U.S. Bureau of Mines (currently NIOSH), Mine Safety and Health Administration, and the coal industry have conducted significant studies to evaluate the performances of face ventilation systems through the use of full scale tests (underground/surface) or scaled physical modeling. These studies have led to recommendations that tend to make these systems more effective. However, because of the aerodynamic complexity in the face area arising from the variety of ventilation arrangements amid limitations of the experimental methods, doubts still exist when evaluating the effectiveness of such a system. The design of a balanced ventilation system for the scenarios described above requires consideration of the system in a three-dimensional, rather than two-dimensional, manner. Traditional theoretical and experimental methods are available for obtaining useful results, but the former is limited to simple geometries and experimental methods are often slow, and both approaches are limited in the completeness, accuracy and generality of the results that they provide. Computational Fluid Dynamics (CFD) is a promising design methodology by which many complicated fluid flow problems can be solved with numerical codes. CFD embraces a variety of technologies, including mathematics, computer science, engineering, and physics, and has potential to generate face ventilation designs without the previously mentioned disadvantages. The major objective of this proposed project was to investigate the feasibility of developing a tool that facilitates the design of face ventilation systems to provide healthier and safer working environments for underground miners. The potential ability of this approach to reliably, quickly, and inexpensively test alternative face ventilation configurations will reduce the time between the generation of a design concept and its implementation by minimizing the tedious and costly experimental work required with existing design methodologies. If feasible, much improved designs for face ventilation systems should result because it will be possible, for the first time, to screen a wide range of alternative configurations and quickly identify the most promising design concepts for a particular field application. To achieve these objectives mentioned above, the authors conducted the following studies: (1) Development of a scaled physical model for examination of various ventilation scenarios and measurement of the airflow patterns using PIV (particle image velocimetry). These will be compared with simulations using commercial CFD software packages (CFD-2000, FLUENT, and CFX) with the objective of validating the CFD approach; (2) To refine modeling (numerical and scaled-physical) approaches, and to confirm that mathematical models and numerical method (CFD) can be used for design purposes of the face ventilation systems the full scale laboratory (gallery) tests will be performed at the Pittsburgh Research Center by the authors in conjunction with the NIOSH, Dust and Ventilation Group; (3) based on the study performed the authors will down select a CFD software package, which could be, in cooperation with the software development company, converted to the specialized design tool utilized by the industry. It was determined that at the present time, CFD is not mature enough to be reliably used for ventilation design, though it can be used during the design process should sufficient validation be available.
Mining-industry; Ventilation; Ventilation-systems; Mining-equipment; Coal-mining; Underground-mining; Models; Computer-models; Simulation-methods
Final Grant Report
Research Tools and Approaches: Control Technology and Personal Protective Equipment
National Institute for Occupational Safety and Health
University of Kentucky