QC-06-041 - Burning Velocity of 1,1-diflurorethane (R-152a) PDF

This paper presents measurements and numerical calculationsof the burning velocity of 1,1-diflurorethane (R-152a,CH3-CHF2), compares the present results to others appearingin the literature, and discusses the influence of flame stretchand other experimental complications on the measured burningvelocities. The measurements have been made in a Mache-Hebra nozzle burner over the range of equivalence ratios0.9 ¡Ü ¦Õ ¡Ü 1.3. Corresponding numerical calculations for asteady, one-dimensional, planar flame have been made usinga comprehensive chemical kinetic mechanism based on 783reversible elementary reactions. The raw experimental dataindicate a peak flame speed (based on the total area method)of 29.3 cm/s, while the numerical calculations predict a valueof 27.6 cm/s, both near ¦Õ = 1.1. Stretch corrections for the conicalBunsen-type flame have been estimated and lower theexperimentally measured values by about 20% for all ¦Õ < 1.05but insignificantly for richer flames. Since flame stretch cansignificantly modify the laminar flame speed and also changethe propensity of the flame to become turbulent (and have amuch higher flame speed), it is suggested that it may be usefulin future tests to use techniques that allow simultaneous determinationof the unstretched laminar flame speed as well as theflame¡¯s response to stretch and preferential diffusion.