ONE-DIMENSIONAL COMPRESSIBLE FLOW IN VANELESS DIFFUSERS OF RADIAL- AND MIXED-FLOW CENTRIFUGAL COMPRESSORS, INCLUDING EFFECTS OF FRICTION, HEAT TRANSFER AND AREA CHANGE

摘要

An analysis method and a design method are developed for one-dimensional, compressible flow-with friction, heat transfer, and area change in vaneless diffusers with arbitrary profiles in the axial-radial plane. The effects of mixing losses due to nonuniform flow conditions at the impeller discharge are not considered. In the analysis method the variations in fluid properties, including the velocity and flow direction, are determined as a function of radius for a prescribed variation in diffuser wall spacing with radius. In the design method the variations in effective diffuser wall spacing and in the fluid properties1 are determined as a function of radius for an arbitrary prescribed variation in one fluid property. For efficient diffuser designs the fluid property selected and the manner in which its variation is prescribed will depend on viscous flow effects that are considered in boundary-layer studies but are not investigated in this report.