NIOSH Ventilation Research Project
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Project goals
- To apply the MULTIFLUX air flow, heat, moisture, and gas transport simulation model to ventilation tasks in deep, hot underground mines and demonstrating its capabilities in accurate predictions.
- To use MULTIFLUX in selected cases by demonstrating improvement in safety and costs.
- To make MULTIFLUX easy to use as a new mine ventilation and contaminant transport model.
- To educate students and technical professionals how to use it.
Description of the research approach
- Add new, necessary components to the MULTIFLUX software and model originally developed and qualified for nuclear waste repository ventilation, heat and moisture simulations.
- Provide the ventilation engineer with an easy–to–use graphical interface for model definition and input data entry.
- Interpret and animate the results graphically.
- Apply the MULTIFLUX model to industrial mine ventilation tasks including applications with Barrick Goldstrike, our in-kind research partner.
- Work with a total of six students as research assistants.
Background of MULTIFLUX
MULTIFLUX Version 5.1 is a qualified software and model, developed for supporting coupled, time-dependent thermal-hydrologic and ventilation calculations in a subsurface opening in a high-level nuclear waste repository. MULTIFLUX is the result of ten years of development by the Principal Investigator, Dr. George Danko. The software validation and qualification work was completed in 2008 (Danko, 2008) under U. S. Department of Energy support, administered through a subcontract to the Lawrence Berkeley National Laboratory. The total research contract revenues related to the development and application of MF have been over $1 M.
- What is new and innovative?
- Advanced transport solver for heat, mass and contaminant flows.
- Mass flow conservation is provided with variable density.
- Total, barometric pressure is simulated, increasing with depth.
- Humidity, evaporation and condensation is modeled with psychometric equations.
- The solver engines are integrated-parameter computation CFD solvers of the governing equations.
- The Numerical Transport Code Functionalization (NTCF) methodology is used to couple the CFD solution to strata heat and moisture (US Patent No. 7610183B2).
- MULTIFLUX is a general multi-component, multi-physic integrated-parameter Computational Fluid Dynamic (CFD) analytical software that solves a complex problem with much fewer nodes than a commercial CFD code.
- MULTIFLUX solves a system of differential equations for a given network of nodes simultaneously. Currently, there is no other mine ventilation software that solves simultaneous networks for heat, moisture, airflow and contaminant transport.
- The coupled network model-elements in MULTIFLUX are solved efficiently and simultaneously: no need to manually iterate between different modules.
Background science in MULTIFLUX
CFD governing equations and corresponding MULTIFLUX model for each grid node:
Basic model elements of MULTIFLUX:
Solution logic flowchart for the MULTIFLUX model:
Numeric example: Mine ventilation network solution from MULTIFLUX
A modern underground mining complex, with a total of 2345 airways and 1979 junctions, adding up to over 58 km in length.
- All the heat sources from diesel equipment based on diesel consumption were applied to the production zones.
- All the fan heat based on 30% fan efficiency are included.
- Gravity, compression/expansion work, and natural ventilation are included.
- A mine-wide average wetness factor of 0.05 was obtained by matching field measurements.
Airflow velocity simulation for the example ventilation network from the MULTIFLUX model.
Temperature distrubution for the example ventilation network from the MULTIFLUX model.
Relative Humidity distribution for the example ventilation network from the MULTIFLUX model.
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