Paper presented at the 6th International Conference on Heat Transfer, Fluid Mechanics and Thermodynamics, South Africa, 30 June - 2 July, 2008.
The main goal of this work is to determine experimentally
local stretch rate distribution along limit methane/air and
propane/air flames – using Particle Image Velocimetry (PIV)
method. It allows to obtain necessary moving flame velocity
fields in a standard flammability column and, also, to recognize
the flame structures. For this purpose each mixture was seeded
with MgO particles (of known size) before entering the tube
(column) – using a special system. The amount of seeds in the
mixture, their dispersion system and the laser power producing
a sheet of light penetrating the column – were carefully chosen
(not to disrupt the combustion or flame propagation in it). After
learning process, finally it allowed to obtain the good quality
velocity field images in the region concern – acceptable for
further processing. The methodology developed for these
experiments proved to be reliable and able to supply analyses
with repeatable data. On the basis of performed experiments it
was possible to derive the flame stretch rate which causes its
extinction for both mixtures.
