Detection and characterization of penetrating pores in porous materials

Sintered porous materials fabricated from powdered super-alloy are considered to be prime candidates for applications requiring transpiration cooling. The characteristics of these materials, especially the distribution and size of the penetrating pores at the surface exposed in high heat flux, are important because they directly affect the cooling and burned-out location. Thus, it is necessary to detect and characterize quantitatively the penetrating pores at the surface. This paper describes a digital image processing technique that was successfully used to detect the penetrating pores at the surfaces of porous plates. It is suggested that the homogeneous dimension minimum concept can be used to describe quantitatively the exterior property of the porous materials.