Lean Flammability Limit as a Fundamental Refrigerant Property. Interim Technical Report. Phase 1. October 1, 1994-March 31, 1995.
Lean Flammability Limit as a Fundamental Refrigerant
Property. Interim Technical Report. Phase 1. October
1, 1994-March 31, 1995.
Womeldorf, C. A.; King, M. D.; Grosshandler, W. L.
DOE/CE/23810-58; 32 p. March 31, 1995.
Sponsor:Department of Energy, Washington, DC
Available from: National Technical Information Service
(NTIS), Technology Administration, U.S. Department of
Commerce, Springfield, VA 22161.
1-800-553-6847 or 703-605-6000;
Order number: DE95-011238
flammability limits; refrigerants; difluoromethane;
pentafluoroethane; counterflow burner
Due to the ozone-depleting effects of commonly used
chlorofluorocarbon refrigerants, safe
environmentally-firendly replacements must be found.
HFC-32 (CH2F2) and other hydrochlorofluorocarbons are
potential candidates; however, in contrast with the
CFCs, many of these compounds are flammable. Testing
the flammability limits of these
hydrochlorofluorocarbons using traditional ASTM E-681
methods has produced a range of limits depending upon
the vessel and ignition source used. This project
demonstrates the feasibility of defining a fundamental
flammability limit of HFC-32, that occurs at the limit
of a zero strain rate and is independent of ignition
source. Using a counterflow twin-flame burner to define
extinction points for different strain rates, an
extrapolation to zero strain rate is performed. Using
this technique, preliminary results on the lean
flammability limit of HFC-32 and the critical
flammability ration of HFC-125 (C2HF5) in HFC-32 are