Numerical simulation on pressure field in chamber of low-voltage circuit breaker in different conditions

For a simplified arc quenching chamber of molded case circuit breaker (MCCB), based on computational fluid dynamics (CFD) software FLUENT, a physical and mathematical model of the high current breaking process of the gas flow and pressure field in arc quenching chamber is built. The erosion of gassing material and contact material, actual arc power is considered in the model. Based on this model, the influence of different arc position, different numbers of bilateral air vents and whether the arc chutes are endothermic on the variation rule of chamber pressure, temperature and velocity with time in arc quenching chamber is simulated and analyzed. The change of arc shape and the temperature distribution on the surface of arc chutes are also obtained by simulation. Simulation results show that with the increasing numbers of bilateral air vents, the maximum pressure in arc quenching chamber decreases. The position of the arc in the chamber affects the maximum pressure value and the moment it appears. Absorbing heat of arc chutes from arc decreases the maximum pressure in chamber.