Three-dimensional simulation of ionic wind in a laminar premixed Bunsen flame subjected to a transverse DC electric field

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https://www.sciencedirect.com/science/article/pii/S001021801930015X

Abstract The role of the ionic wind effects on modifying flame dynamics was demonstrated by detailed computational models. Full three-dimensional simulations were conducted to reproduce and describe the response of a laminar premixed methane–air Bunsen flame subjected to a transverse DC electric field at saturation condition. The chemical kinetic mechanism employed a methane–air skeletal mechanism with an optimized ionization model to predict the positive and negative ions that are important for generating the electric currents. Given the strong dependence of the ionic wind on the amount of charged species created by chemi-ionization, the ion production rate was optimized to match the measured saturation current. The simulation successfully reproduced the flame tilt toward the cathode. The ionic winds blowing from the flame toward the electrodes in both rightward and leftward directions were also captured. The calculated flow field is qualitatively consistent with the PIV experimental data. Accurate description of the three-body electron attachment to oxygen and the charge transfer reactions generating heavy anions was found to be critical in simulating the flame–electric field interaction. This is a first demonstration of the ionic wind effect by full three-dimensional simulations. Further investigation by both experiment and modeling are required in future work to address quantitative differences.

[syoukera]

なんで3次元でやる必要があったのか？もちろん，実験装置が軸対象のバーナに横方向に電界を印加しているので次元を落とせないというのは，まあ，理解できる．しかし，対向流などの場を選べば1次元で計算可能なのではないかしら． 実際の実機の状態に近づけたかったということだろうか．火炎同士の相互作用，曲率の影響，電界印加の方向をへんこうすること

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背景

The electric field effects on the flame shape and surrounding flow field has been extensively discussed [3], [8], [9], [20], [21]. While phenomenological explanations for the observed effects are available providing qualitative physical understanding, the role of some important ionization processes is still not fully understood. In particular, further investigations are required in order to describe the key processes relevant to the role of negative charges.

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However

integrating such detailed models into multi-dimensional simulations incurs a significant computational challenge, especially considering that the electron drift velocity demands an extremely small time step [23], [24].

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