Flow analysis in valve with moving grids through CFD techniques

The compressible air flow in a typical puffer chamber with moving contact between fixed electrodes has been studied using computational fluid dynamics techniques. Moving grid methods in CFD process not only plays a pivotal role in understanding the flow behavior in time domain but also helps for fixing the internals at optimal locations. A typical laboratory puffer chamber geometry has been extracted from the published literature and generated multi-block structured grid using Altair's HyperMesh software. Flow simulation in axi-symmetry duct comprises fixed electrodes, moving contact and exit duct has been carried out with ANSYS-CFX software. It has been observed that, due to steps and curvature in the geometry, flow takes different turns from inlet and velocity distribution between fixed electrodes indicates vortex flow with turbulent eddies. CFD simulation with valve element mesh motion indicates that pressure history is significantly affected by the velocity of moving contact in the puffer chamber. The results obtained for a typical puffer chamber with the mesh motion are qualitative in nature and forms the sound basis for future design studies of electro-fluid dynamics of circuit breakers. (C) 2008 Elsevier Ltd. All rights reserved.