Accession Number : AD0463022

Title :   THE EFFECT OF SOUND ON THE NORMAL VELOCITY AND STABILITY LIMITS OF LAMINAR PROPANE-AIR FLAMES,

Corporate Author : WISCONSIN UNIV-MADISON THEORETICAL CHEMISTRY INST

Personal Author(s) : Loshaek, Sam ; Fein, R. S. ; Olsen, H. L.

Report Date : 09 JUL 1949

Pagination or Media Count : 1

Abstract : The application of sound of known intensity and a frequency of 12.7 kc to a laminar propane-air flame is found to produce a shift in the stability limits of the flame. The sound alters the flashback limit so that the flame becomes more stable and the blowoff limit so that the flame becomes less stable. The normal burning velocity is not changed with the application of sound and that the flow velocity profile in the tube is likewise unchanged. From the Lewis and von Elbe theory of flame stabilization it is then concluded that the penetration distance must be increased. The penetration distances are calculated from the flow velocity distribution and the normal burning velocity and, near stoichiometric, are found to increase about 20% at the maximum sound intensity of 10 milliwatts/sq cm. Sound at a frequency of 18.3 kc affects the blowoff limit in a similar manner as the lower frequency but no appreciable effect is noted on the flashback limit. It is concluded that these results in combination with further experimental studies should yield useful information about the nature of the penetration distance and flame holding in general, but that sound at these low frequences does not offer a useful tool for studying flame propagation. (Author)

Descriptors :   (*FLAMES, STABILITY), HYDROCARBONS, AIR, SOUND, BURNING RATE, VELOCITY, DISTRIBUTION, FREQUENCY, PENETRATION.

Distribution Statement : APPROVED FOR PUBLIC RELEASE