Influence of the dissociation unit on pressure and temperature distribution in arc chamber of ACB during the breaking process

To void breakdown between busbars, the dissociation unit is applied in the arc chamber of an air circuit breaker (ACB) to cool down the hot gas exhausted from the vent of the arc chamber in the interrupting process. Cooling efficiency and flow resistance of the dissociation unit have important roles, which can greatly affect the safety of the low voltage switcher and interrupting performance of the arc chamber. The most common structure style of the dissociation unit is a multilayer metal wire mesh, and it has a complex microstructure. Then, it is unreasonable to directly simulate the dissociation unit due to the huge cost of calculation. In this study, the porous medium model is introduced and a combination of two different porous materials is applied to simplify the simulation model of the dissociation unit. Based on the porous model and simplified arc chamber model, the ACB with the dissociation unit is analyzed. The cooling effect and flow resistance of the dissociation unit are evaluated in the breaking process. By comparing experimental and simulated pressures in the arc chamber, this simulation approach is verified.