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Numerical Investigation of Different Ventilation Systems in Coal Mines Effects on the Fire Extinguishing

Kavkar Moghaddam, Erfan | 2020

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  1. Type of Document: M.Sc. Thesis
  2. Language: Farsi
  3. Document No: 53224 (08)
  4. University: Sharif University of Technology
  5. Department: Mechanical Engineering
  6. Advisor(s): Afshin, Hossein; Farhanieh, Bijan
  7. Abstract:
  8. In recent years, due to fires in mines around the world, the need to study the dynamic behavior of fire to understand how it spreads and design an appropriate fire extinguishing system to reduce damage to people and underground facilities has been felt. Mine fires are usually caused by external sources such as cable connections, methane gas explosions, or coal self-ignition due to oxygen uptake and rising temperatures.In this research, using Fire Dynamic Simulator (FDS) software, after drawing the geometry of a coal tunnel corridor in progress and creating a fire model through pyrolysis of PVC, fire extinguishing was performed by nozzles. If the nozzle does not succeed in extinguishing the fire, which depends on an experimental variable called the extinguishing coefficient, the two scenarios of air suction and inert gas injection will start working after a certain period of time. The results of the simulations show that the efficiency of the nozzle connected to the thermocouple is better than the sprinkler. Water mists will be more effective in extinguishing fires than similar nozzles. Air suction will have a better effect in reducing the temperature than gas injection, but will cause the fire to move towards the entrance of the mine. Using pure carbon dioxide and a mixture of two gases, carbon dioxide and nitrogen, instead of using pure nitrogen, causes the fire to be extinguished faster, but increases the concentration of carbon dioxide throughout the mine to a deadly level. Also, the presence of a branch in a mineral tunnel corridor, in addition to providing an evacuation route from the injured area, will increase the length of time that different parts of the tunnel remain safe from temperature and harmful gases from the fire; If the branch is close to the fire, it will develop the fire and make it difficult to control due to the oxygen it needs. Also, the blowing fan, despite the faster extinguishing of the fire, will increase the concentration of harmful substances and also reduce the field of view throughout the geometry
  9. Keywords:
  10. Fire Extinguisher ; Air Intakes ; Sprinkler Nozzles ; Nozzles ; Water Mist Nozzles ; Inert Gas Injection ; Fire Dynamics ; Fire Dynamic Simulator (FDS)Software

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