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Lean Flammability Limit as a Fundamental Refrigerant Property. Interim Technical Report. Phase 1. October 1, 1994-March 31, 1995.


pdf icon Lean Flammability Limit as a Fundamental Refrigerant Property. Interim Technical Report. Phase 1. October 1, 1994-March 31, 1995. (1443 K)
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.
Telephone: 1-800-553-6847 or 703-605-6000;
Fax: 703-605-6900.
Website: http://www.ntis.gov
Order number: DE95-011238

Keywords:

flammability limits; refrigerants; difluoromethane; pentafluoroethane; counterflow burner

Abstract:

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 reported.