Pressure drop measurements for woven metal mesh screens used in electrical safety switchgears

Abstract

The paper deals with an experimental investigation of the pressure drops and friction factors induced by sets of metal woven screens in the case of an incompressible fluid flow, namely water flow. These woven screens are of metallic type and are used in electrical safety devices, especially at the end of exhaust duct of low voltage circuit breakers. In a first step, the whole of the set-up is used to check some approxima- tions dedicated to pressure drops due to sphere beds around 275 μm and 375 μm as diameters. Results are discussed in terms of Darcyan and non-Darcyan permeabilities compared with published data and are analyzed in terms of the Blake-type friction factor. In the second step, the pressure drops are mea- sured for stacks composed of eight different woven screens (of plain dutch type) formed with millimetric wires. Various formulations of the pressure drops and friction factors published elsewhere are tested with a special care dedicated to the choice of the geometry for the flow pattern (hydraulic diameter, spher- ical diameter, cylindrical diameter) and to the consideration of laminar and turbulent contribution. We then give the formulation that characterizes the fluid flowing through stacks of woven screens used in electrical safety applications.