Abstract An investigation of the influence of different degrees of confinement on flame acceleration due to repeated obstacles has been performed in a 1.22-m-long channel. Confinement is controlled by venting the urburned and product gases through a perforated plate of the channel. It is found that confinement plays an important role in determining the strength of the positive feedback mechanism which accelerates the flame. By venting through the top perforated plate, the unburned gas flow ahead of the flame which convects the leading front forward is greatly reduced. The turbulence intensity is also descreased from a reduced flow velocity. To identify the role of confinement on flame acceleration, a model is used to describe the flame propagation in the partially confined environment under consideration. With only one parameter from fitting with experimental data, the model predicts fairly well the variation in flame speed for various different degrees of confinement.
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