Geometry and Dynamic Scaling for a 1/40th Scaled Physical Model of a Longwall Coal Mine


Richard Gilmore, Colorado School of Mines; Jason McMack, Colorado School of Mines; Casey DeRosa, Colorado School of Mines; Gregory Bogin Jr., Colorado School of Mines; Jürgen Brune, Colorado School of Mines

Researchers at the Colorado School of Mines are currently designing and building a scaled version (1/40th) of a longwall coal mine which will allow the variation of ventilation conditions and mine conditions. The goal of the study is to provide insight into the optimal placement of methane sensors, based on various ventilation and mine layout scenarios, along with providing insight into the potential hazards of a methane explosion, and how the design of ventilation and mine layout could have an impact on the severity of an explosion. The model addresses the need for an improved mine-wide Atmospheric Monitoring Systems (AMS) and provides the ability to link existing Mine Ventilation System (MVS) models with AMS in real time. For the purpose of developing suitable scaling factors for the model, various CFD models were created in ANSYS Fluent, both full-scale and 1/40 scale. The models include details such as the shields, belt, and shearer in order to generate realistic flow patterns. With these highly detailed models, researchers were able to study the effects of varying flow parameters such as the Reynolds or Richardson number and their effect on the flow. Based on a comparison of data gained from the scaled with the full-scale model, the researcher created parameters for scaling of the airflow. Further, researchers were able to show that reducing the Reynolds number from 500,000 in the full-scale model to 50,000 in the 1/40 scale model showed comparable results.