Curran, Donald C. (1953) An experimental study of the stability of laminar flame. Engineer's thesis, California Institute of Technology. http://resolver.caltech.edu/CaltechETD:etd-04222003-101645
Knowledge of laminar flame front structure is insufficient to make exact stability calculations possible. The analysis of Landau(1) indicated flame front instability under all conditions. Semi-empirical corrections to Landau's result by Markstein(2) demonstrated that a cellular flame front structure that Markstein observed experimentally might be a stable configuration. Karlovitz(3) has proposed that there is a significant additional amount of turbulence produced in turbulent flames over that found in the upstream flow. Of particular significance is the question of whether or not a flame may take on a turbulent structure in the absence of upstream turbulence.
Therefore explorations concerning the conditions under which a laminar flame might become unstable were undertaken by burning premixed propane and air using a spherical flame holder.
The resulting conical flame had annular waves develop in the flame front a short distance downstream from the flame holder. This distance decreased as fuel-air ratio was decreased and as gas mixture flow velocity increased. Lean high velocity flames showed a parallel result in the amplitude of the wave formed - the wave in this case developing to a large amplitude in a short distance with a tendency to roll up.
Another result of the investigation was that a fairly uniform wavelength of 0.27 in. was observed even though mixture, flame holder size and flow rate were varied.
The introduction of a small external turbulence source upstream of the flame front disturbed the flame - the amount of disturbance increasing with Reynolds' number of the turbulence source and with fuel-air equivalence ratio.
|Item Type:||Thesis (Engineer's thesis)|
|Degree Grantor:||California Institute of Technology|
|Division:||Engineering and Applied Science|
|Major Option:||Engineering and Applied Science|
|Thesis Availability:||Public (worldwide access)|
|Defense Date:||1 January 1953|
|Default Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited By:||Imported from ETD-db|
|Deposited On:||22 Apr 2003|
|Last Modified:||26 Dec 2012 02:38|
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