Burning velocity of 1,1-diflurorethane (R-152a)

This paper presents measurements and numerical calculations of the burning velocity of 1,1-diflurorethane (R-152a, CH 3 -CHF 2 ), compares the present results to others appearing in the literature, and discusses the influence of flame stretch and other experimental complications on the measured burning velocities. The measurements have been made in a Mache-Hebra nozzle burner over the range of equivalence ratios 0.9≤Φ≤1.3. Corresponding numerical calculations for a steady, one-dimensional, planar flame have been made using a comprehensive chemical kinetic mechanism based on 783 reversible elementary reactions. The raw experimental data indicate a peak flame speed (based on the total area method) of 29.3 cm/s, while the numerical calculations predict a value of27.6cm/s, both near Φ = 1.1. Stretch corrections for the conical Bunsen-type flame have been estimated and lower the experimentally measured values by about 20% for all Φ < 1.05 but insignificantly for richer flames. Since flame stretch can significantly modify the laminar flame speed and also change the propensity ofthe flame to become turbulent (and have a much higher flame speed), it is suggested that it may be useful in future tests to use techniques that allow simultaneous determination of the unstretched laminar flame speed as well as the flame's response to stretch and preferential diffusion.