Abstract
It is well known that there are numerous micro-particles and micro-protrusions on electrodes surface in vacuum gaps. The vacuum breakdown mechanisms initiated by the micro-particles and the micro-protrusions have been studied during the vacuum pre-breakdown processes. However, there is no quantitative research on interaction effect between the micro-particles and the field emission electrons based on the nonideal micro-protrusions in different vacuum gaps. In this paper, by means of a micro-protrusion model based on the fractal theory and the micro-particle dynamic equations, the anode micro-particle characteristics under the bombardment of the field emission electrons in different vacuum gaps are investigated quantitatively. The results show that the bombardment of the field emission electrons has a significant influence on the dynamic characteristics of the micro-particles. There is a close relationship between the vacuum gap and the dynamic characteristics of the micro-particles. With a vacuum gap less than 1.0 mm, the maximum temperature of the micro-particles would eventually reach the boiling point and the evaporation rate would reach 97 kg-m−2·s−1. With a vacuum gap more than 5.0 mm, the maximum temperature would not reach the boiling point and the evaporation rate would decrease to zero. Furthermore, in a vacuum gap more than 5.0 mm, there are more obvious impact phenomena occurred between the cathode and the micro-particle than that in a vacuum gap less than 1.0 mm. The results of this paper may provide some useful information to understand the physical mechanism of vacuum breakdown.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call