Magneto hydrodynamic simulation coupled with network in low voltage circuit breakers

NS2 is a 2D hydrodynamic CFD code, developed by Schneider Electric, under permanent upgrading & improvement. This code leans on the Navier Stokes equations and an electromagnetic model (Biot and Savart Law). It is used to simulate the electrical arc behavior and gas flow in low voltage circuit breaker. Real gas thermodynamical data are used for calculation. Specific energy phenomena such as radiation and arc roots losses are taken into account. The moving contact is represented thanks to a moving mesh. Thanks to those magneto hydrodynamic calculations, the arc voltage is calculated and inserted into the network simulated by a voltage source, a resistance and an inductor. Then, numerical voltage, current and arc energy, which are rather easy to measure on a circuit breaker, are compared with experimental results and adjustments of the model are discussed. Then, the code permits a fine analysis of hydrodynamic and electromagnetic phenomena inside the apparatus.