FUNDAMENTAL FLAME VELOCITIES OF PURE HYDROCARBONS III - EXTENSION OF TUBE METHOD TO HIGH FLAME VELOCITIES - ACETYLENE-AIR MIXTURES

摘要

The tube method of measuring flame velocities has been extended to fundamental flame velocities of 141 centimeters per second. This extension was accomplished by reducing the flame-tube diameter from 25 to 12.5 millimeters. The reduction in flame-tube diameter decreased the Reynolds number of the unburned gas ahead of the flame from a turbulent to a laminar region. The gas-velocity correction in the 12.5-millimeter flame tube fits the empirical linear relation between gas velocity and spatial flame velocity previously obtained in the 25-millimeter flame tube. The ratio of the flame-tube cross-sectional area to the flame surface area was found to be the same constant in the 25- and the 12.5-millimeter flame tubes. A simplified equation for calculating the flame surface area from flame photographs is presented.nThe maximum fundamental flame velocity of acetylene-air mixtures was found to be 141 centimeters per second, which is in satisfactory agreement with Bunsen burner results.