'Periodica Polytechnica Budapest University of Technology and Economics'
Abstract
An experimental investigation has been carried out to study flammability limits of the
natural gas and the effect of flame holder position, in the burner tube, on it. These tests
employed two shapes of bluff body: disk and cone (600
included angle) with blockage
ratio of 0.42. The fuel used was natural gas and the upstream air velocity was varied up
to 26 m/s. The flame holder location was varied from 12 mm inside the burner tube, with
respect to the burner mouth, to 12 mm downstream and outside it (hid from -0.44 to
+0.44). The results showed that the flammability limits are widened due to the use of
bluff body and it depends largely on the flame holder shape and position in the burner
tube. The results showed also that the best position of the flame holder is not the same
for all shapes of the bluff bodies, but it depends on the shape of the flame holder and
on the nature of study (lean limit or rich limit). For the lean limit of flammability, it
is concluded that the best position of the flame stabilizer is at 6 mm inside the burner
tube (hid = -0.22) for disk bluff body and 12 mm outside it (hid = 0.44) for the conical
one. For the rich limit the best position is 6mm outside (hid = 0.22) for disk and 12mm
outside also (hid = 0.44) for cone
