The Influence of Nozzle Design Elements on the Pressure and Flow Velocity During Opening Process

During current breaking of gas filled circuit breaker, the compression chamber should rapidly establish a sufficiently high gas pressure. A nozzle is one of core components of a circuit breaker, and is used to form high-speed gas flows between the breaks. Its design parameters can affect both the pressure buildup effect in the compression chamber and the gas flow velocity in the nozzle throat during breaking process, which then affects the interruption performance of the interrupter. In this paper, based on fluid simulation software, we simulate the pressure in the compression chamber and the gas velocity in the nozzle throat during the no-load opening process, and subsequently analyze the effect of different design parameters of the nozzle.