Simulation of arc in molded-case circuit breaker with metal vapor and moving electrode

The behavior of arc in molded case circuit breaker is studied by computational fluid dynamics simulation (CFD) with moving electrode taking account of the metal vapor (Cu, Ag/W, Fe) and the decomposed gases (CO2, H2). The background fluid is air and the electric current is 820A DC. The circuit breaker consists of copper electrodes, arc runner, magnet, splitter plates and molded case. The mesh-morphing and re-meshing technique is used to represent the motion of electrode. With local thermal equilibrium (LTE) assumption, thermodynamic property of arc plasma is calculated by temperature, pressure, and gas composition. The simulation is performed by commercial software STAR-CCM+. It is shown that the motion of arc from electrode to arc runner is reproduced successfully, and the cooling effect of metal vapor has significant influence on the temperature of arc plasma.