Flame Propagation Along a Fine Vortex Tube

ABSTRACT

Interaction between a premixed flame and a fine vortex tube perpendicular to the flame is simulated numerically in order to study the effects of the rotating velocity and tube diameter on flame propagation along the vortex tube. The vortex tube has an initial circumferential velocity ranging from 1.8 to 36 times the laminar burning velocity and an initial core diameter ranging from 0.18 to 1.71 times the flame thickness. It is shown that a premixed flame can be accelerated along the vortex tube axis, and that the propagation velocity is proportional to the maximum circumferential velocity of the vortex tube. It is also shown that the influence of the vortex on the flame propagation can be neglected when the Reynolds number based on the vortex tube diameter and maximum circumferential velocity is below 10. The proportionality factor between the propagation velocity and circumferential velocity increases above the critical number with azimuthal speed and reaches about one at the Reynolds number of about 60.

Key Words:

• Premixed flames
• concentrated vortices
• flame speed
• vortex bursting
• turbulent flames