The determination of end-wall blockage in axial compressors: A comparison between various approaches

The end-wall blockage in axial compressors has been the subject of several investigations over a period of many years. This paper reviews and compares various approaches to determining the blockage, particularly in the ''repe ating" stage, a stage deeply embedded in the compressor where an equilibriu m stale is reached, the flow through any one stage repeating in the next. T hese approaches include: (i) correlations of displacement thickness measure d in compressor rigs; (ii) a relationship between outlet blockage and the c learance area, based both on an empirical development of a simple model of the flow through the clearance space and full CFD calculations of the flow; (iii) momentum analysis of the flow through the blockage region, developed from the boundary layer analyses of some years ago, but not now relying on boundary layer concepts. [S0889-504X(00)01502-6].