The design of the vaned diffuser of a centrifugal compressor is still based on a considerable amount of empiricism in its design methodology. Parameters such as area ratio and blockage, which are more relevant to conical diffusers, are used in conventional design practice.
Fracture as a material sink
Cracks are created by massive breakage of molecular or atomic bonds. The latter, in its turn, leads to the highly localized loss of material, which is the reason why even closed cracks are visible by a naked eye. Thus, fracture can be interpreted as the local material sink. Mass conservation is violated locally in the area of material failure. We consider a theoretical formulation of the coupled mass and momenta balance equations for a description of fracture.
