Characterization of flow through porous metals

Porous metals have long been considered as an ideal material in which to manufacture turbine components given the inherent large convective surface area. One consideration, however, in using porous metals is the increase in pressure drop that accompanies these materials. To characterize increases in pressure drop for porous materials, flow measurements were made on numerous porous metal coupons. The porosity of the coupons investigated had a range of four in terms of density. A technique for determining the effective internal flow area from pressure drop measurements was developed to provide an effective diameter. The pressure drop measurements were compared to an ideal isentropic compressible-flow nozzle and to a smooth, straight-walled tube. The comparisons show that the porous channels have a similar, but much larger pressure drop than the smooth walls. The experiments performed demonstrated that these porous geometries can be scaled to provide generalized pressure drop characteristics for all geometries.