Dynamic Behavior of Droplets and Flashover Characteristics for CFD and Experimental Analysis on SiR Composites

The dynamic mechanism of water droplet formation has recently drawn considerable attention in research and application toward silicon rubber composite insulators. This paper is aimed at numerical simulations and experiments on the dynamic mechanism of water droplet formation with different applied voltages and droplet distribution and induced surface discharges on the insulator surface under the impact of AC electric field. The computational fluid dynamics model and experimental setup of multiple droplets were established to analyze the dynamic behavior of droplets and flashover characteristics. The obtained results reveal that the fusion first occurs between larger size droplets and the fusion is hard to happen along with the rise of the fractal dimension (FD) of droplet distribution. The elongation of droplets merges with more droplets and finally affects the electric field distribution on the insulator surface. With the increase of FD, the maximum electric field intensity shows an increasing tendency. Meanwhile, the experimental results show that with the increase of electric field intensity, the droplet fusion phenomenon becomes more obvious, which is consistent with the simulation results. The flashover voltage on the surface of silicon rubber decreases with the decrease of the FD of droplets, indicating that the complexity of droplet distribution has a significant effect on the flashover voltage.