- Author
- Cooper, L. Y.
- Title
- Dispersion of Fire Suppression Agents Discharged From High Pressure Vessels: Establishing Initial/Boundary Conditions for the Flow Outside the Vessel.
- Coporate
- National Institute of Standards and Technology, Gaithersburg, MD
- Sponsor
- Air Force, Wright Patterson AFB, OH
- Report
- NISTIR 5219; Paper XIII-2, September 1993, 37 p.
- Distribution
- Available from National Technical Information Service
- Book or Conf
- Institute for Liquid Atomization and Spray Systems (ILASS-Europe) and CORIA. Liquid Atomization and Spray Systems, 6th International Conference Proceedings. ICLASS 94. July 18-22, 1994, Begell House, Inc., NY, Rouen, France, Yule, A. J.; Dumouchel, C., Editors, 1031-1038 p., ['1993', '1994']
- Keywords
- fire extinguishing agents | aircraft safety | discharge pressure | fire extinguishment | fire safety | halons | fire suppression | halon alternatives | pressure vessels
- Identifiers
- halon alternatives
- Abstract
- This work reports on part of an effort to study the dispersion and extinguishment effectiveness of Halon and Halon-alternative fire extinguishment agents discharged from N₂-pressurized vessels. In the systems under consideration, as the agent exits from the vessel, thermodynamic and fluid-dynamic instabilities lead to flashing and break-up of the agent into a two-phase droplet/gaseous jet mixture. This occurs in a transition region relatively close to the vessel exit orifice/nozzle. Downstream of this region the two-phase agent jet then mixes with the ambient air environment and is dispersed in the protected space. A mathematical model has been developed previously to simulate the time-dependent discharge of the agent from the pressure vessel. Using the output of this model and thermodynamic and fluid-dynamic considerations of the phenomena in the transition section, the present work develops a method for determining a set of initial/boundary conditions at an initial section of the jet, downstream of the transition region. These initial/boundary conditions are in a form that can be used to formulate and solve the problem of the development and dispersal of the ensuring mixed air/two-phase-agent jet. Example applications of the developed methodology are presented. These are for agent discharge from a half-liter cylindrical discharge vessel with a circular discharge nozzle/orifice of diameter 0.019m. Simulations involve discharge of the vessel when it is half-filled with either Freon 22 or Halon 1301 and then pressurized with N₂ to 41.37x10⁵Pa (600 psi).