Laminar burning velocities of methane-air flames

Pritchard, R

Abstract

The properties of methane are of considerable significance at
the present time in the United Kingdom following the discovery of
large quantities of natural gas under the North Sea.
One property of particular interest, mainly because of its
importance in connection with flame stability is burning velocity.
The concept of burning velocity as a physicochemical constant
for a particular reactant mixture was first suggested by Mallard and
Le Chatelier (l) nearly a century ago when they referred to "la
vitesse normale", a characteristic of "deflagration" as distinct
from detonation. Over thirty years ago, Coward and Payman (2)
considered that "the fundamental speed of flame is the most difficult
of all the factors to analyze .... and when physicochemical hypotheses
are formulated, they must be tested by measurements of the fundamental
speed. What measurements are available?" The derivation of burning
velocities for hydrocarbon-air flames from fundamental data is now a
not-too-distant prospect (3) following the development of a satisfactory
predictive method for hydrogen flames. However, until this becomes
fact, and afterwards for comparative purposes, we must reiterate Coward
and Payman's question. "What measurements are available?"
There are in fact many measurements available; the burning
velocity of methane-air flames has been the subject of many experimental
investigations over the years. However, there exist considerable
differences in the results of various workers (b) and no agreement on
a standardized method exists.
Furthermore the range of mixture composition over which burning
velocity data are available is somewhat limited.
As Andrews and Bradley (It) have recently stated, although the
theoretical definition of burning velocity is simple, unfortunately
the same cannot be said of its practical measurement.
The theoretical definition of burning velocity relates to the
unidimensional flame model and is the velocity with which a plane
flame front moves normal to its surface through the adjacent unburned
gas. It is an invariant property of the reactant mixture depending
only on the composition and state of the initial mixture.

Citation

Pritchard, R. Laminar burning velocities of methane-air flames. (Thesis). Salford : University of Salford

• Thesis Type: Thesis
• Deposit Date: Oct 3, 2012
• Award Date: Jan 1, 1972