Prediction of combustion promotion effect of high/low-frequency AC electric fields based on machine learning method

•An AC electric field can affect the flame propagation and combustion process of CH4-N2-O2 lean mixture.•The flame front under the high-frequency AC electric field is more stable.•The promotion effect of high-frequency AC electric field on flame and combustion is more significant in lean burn conditions.•The ANN method has higher calculation efficiency than the SVM model.•The model established by machine learning method has great generation ability and prediction performance.