Calculation method of spherically expanding flame propagation radius to consider ignition electrode effects.

Ignition electrodes have an immense impact on the accurate measurement of the flame propagation spherical radius. In this study, a flame-radius calculation method is designed. The method is able to eliminate effects due to the ignition electrodes. The adaptability and optimization effects of the proposed method are analyzed. The results show that the ratio of the angle is affected by the ignition electrodes under the Han II method. There are three obvious divisions include a high-value area, a sharp-variation area, and a mild-variation area. The ratio of the angle affected by the ignition electrodes is only applicable to the mild-variation region when the flame presents respective convex and concave distributions. For these distributions, the increment rate of the mean radius is 0.4-0.85% and 0.42-3.19%. The reduced rate of the standard deviation of the radius extraction value is 11.91-22.1% and 5.13-17.99%, and the reduced rate of the radius extraction value range is 20.32-39.51% and 0.32-8.09%.