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Publication: Premixed flames stabilized in narrow channels: Effect of chemical heat release on interfacial flame/wall energy transfer.

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Title Premixed flames stabilized in narrow channels: Effect of chemical heat release on interfacial flame/wall energy transfer.
Authors/Editors* G.M.G. Watson and J.M. Bergthorson
Where published* Proceedings of the 2010 Spring Technical Meeting of the Combustion Institute/Canadian Section
How published* Proceedings
Year* 2010
Volume
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Pages
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Abstract
This study investigates a flame stabilized in a channel with an axially varying wall tem- perature gradient. In this geometry, the tube diameter is of the same order as the flame thickness. Interfacial energy transfer between the gas and the wall is governed by the wall temperature and an axially developing thermal boundary layer. The thermal boundary layer has a dominant effect in the flame zone. The effect of non-linear heat release on the rate of interfacial heat transfer is studied experimentally and numerically to understand its effect on flame stabilization in narrow channels. In the experiment, a 1 mm quartz tube is heated by an external heat source forming the axial temperature gradient along the wall of the tube. The apparatus is designed to minimize the effect of heat recirculation while allowing the combustion wave to be studied visually. Stoi- chiometric methane/air flames are stabilized at different positions along the wall temperature gradient over a range of inlet flow velocities. The flames are simulated with a numerical model that takes into account heat released due to chemistry and heat lost from the reaction zone due to enhanced heat transfer to the tube wall. In the model, the detailed structure of the flame is determined by employing a coupled numerical formulation which consists of a one-dimensional flame to model the axial diffusion and chemistry and a two-dimensional boundary layer to capture the effects of the boundary layer on flame/wall energy transfer. Results obtained from this model are validated against data obtained from the experiments to test the model’s ability to predict trends in flame stabilization position.

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