In order to explore the influence of DC electric field on combustion characteristics of ammonia/hydrocarbon mixed fuel

the influence of positive or negative DC electric field on flame propagation characteristics of methane/ammonia/air premixed laminar flow is studied on a constant volume combustion bomb bench. The experiment is divided into two parts: under normal temperature and pressure

the excess air coefficient is kept constant

the mixing ratio of ammonia in methane/ammonia mixture is changed

and the methane/ammonia/air mixture with different proportions is loaded with positive or negative direct current fields

respectively; the mixing ratio of ammonia in methane/ammonia mixture is kept constant

and the methane/ammonia/air mixtures with different excess air coefficients are loaded with positive or negative DC electric fields

respectively. After processing the experimental results

the flame propagation development image

the average flame propagation speed

the speed improvement rate

the complete combustion time and the complete combustion time advance rate are obtained under various conditions. The results show that the promotion effect of negative DC electric field is slightly stronger than that of positive DC electric field. The stretching effect of negative DC electric field on flame is approximately a rounded rectangle

while that of positive DC electric field is approximately fusiform

and the stretching effect increases with the increase of the ammonia mixing ratio and the excess air coefficient. The positive or negative DC electric fields can accelerate flame propagation speed and shorten the complete combustion time

and the promotion effect increases with the increase of voltage value. On the other hand

the promotion effects of both electric fields will increase with the increase of ammonia mixing ratio and excess air coefficient. This experiment shows that the high voltage DC electric field can obviously promote the lean combustion of ammonia/hydrocarbon fuel mixture.