Interaction of lean premixed flame with active grid generated turbulence
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The present work adopts an active turbulence grid (ATG) with an aim to study the interaction of a premixed flame with isotropic turbulence. The ATG allows control over turbulence intensities and integral length scales independent of mean velocity. Active grid generated turbulence is characterized using hot-wire anemometer in a non-reacting flow. A lean V-flame interacting with active grid generated turbulence is investigated. Simultaneous particle image velocimetry and OH-planar laser induced fluorescence are performed to deduce the velocity and the scalar fields, respectively. Proper orthogonal decomposition (POD) is applied to these scalar and the velocity fields. Further, the flame surface density is evaluated to quantify the extent of flame wrinkling. The statistics of tangential strain along the flame front is evaluated as well. The POD shows flapping modes and turbulent fluctuations of the flame. The energetic modes correspond to the flapping modes, whereas the flame dynamics pertaining to the turbulent fluctuations are found in lower energy modes. The mode shapes of the lower energy modes are found to be physically meaningful as they compare well with the instantaneous realizations. The lower energy modes are as important as the energetic modes to capture the complete dynamics. ATG is recommended for combustion studies if the effect of relatively larger integral scales needs to be investigated.
This research was supported by Gas Turbine Enabling Technologies Initiative, and the National Centre for Combustion R&D is supported by the Department of Science and Technology, Government of India.
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