Variation of Burning Velocity with Pressure

Author: Pardee, William McKnight

Year: 1953

Degree: Engineer's thesis

Advisor: Marble, Frank E.

Committee Member: Unknown, Unknown

Option: Aeronautics

DOI: 10.7907/C95P-BV39

Abstract

A review of some of the recent theories of steady state flame propagation in gaseous mixtures reveals a considerable difference in their prediction of the effect of pressure on burning velocity. Furthermore, the experimental data obtained by various workers in the field indicate widely different trends. In some cases burning velocity appears to be independent of pressure whereas in other cases it appears to increase as the pressure is reduced below atmospheric. Hence, as a possible aid in discovering more about the mechanism of flame propagation, the burning velocity of several gaseous mixtures was studied over the general pressure range from 100 to 700 mm Hg absolute.

The mixtures used were acetylene-oxygen, acetylene-air, acetylene-oxygen-nitrogen, ammonia-oxygen, ammonia-oxygen-nitrogen, carbon monoxide-oxygen, carbon monoxide-air, and propane-air. Using the burner-visual cone-area method with burners of various sizes, the following results were obtained: for all the above mixtures, except propane-air, the burning velocity is independent of pressure; for propane-air mixtures, the burning velocity varies as P[superscript -.13]. These results are valid provided the burner size is large enough to nullify the effect of quenching.

It is concluded that these results definitely do not support the Tanford and Pease theory that burning velocity varies as P[superscript -.25].

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