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Details for article 13 of 15 found articles
| Title: |
The Effect of Pressure Variations on Premixed Flames |
| Author: |
Peters, N. Ludford, G.S.S. |
| Appeared in: |
Combustion science and technology |
| Paging: | Volume 34 (1983) nr. 1-6 pages 331-344 |
| Year: |
1983-12-01 |
| Contents: |
A thermal theory is developed to explain the experimentally observed effect of pressure changes on the propagation velocity of premixed flames. The theory uses a one-step reaction and large activation energy asymptotics in the framework of a slowly varying flame analysis. A one-dimensional unsteady flame with Lewis number ℒ equal or unequal to unity is considered. The Mach number is assumed to be low enough such that spatial pressure gradients can be neglected. The asymptotic analysis requires a small temperature variation of the unburnt gas due to pressure changes-this condition is satisfied in the limit of large heat release. The analysis shows that pressure changes affect the flame velocity in two direrent ways, through the change of the enthalpy balance in the preheat zone and through the change of flame temperature. An ordinary differential equation for the time variation of the normalized mass burning rate is derived. This equation is analysed for ℒ=l and constant relative pressure decrease to derive a quenching condition for a flame in an expanding chamber. A comparison with experimental data is performed. The effect of stochastic pressure changes is analysed for Lewis numbers different from unity on the basis of a Fokker-Planck equation. These results indicate a drift of the mean velocity towards small values even in the stable case ℒ<1, while in the unstable case ℒ>1 the mean becomes infinitely large immediately. |
| Publisher: |
Taylor & Francis |
| Source file: |
Elektronische Wetenschappelijke Tijdschriften |
Details for article 13 of 15 found articles
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