An analysis of the effect of principal design variables on the stagewise design-point characteristics of multistage axial-flow compressors was made in order to determine whether the average stage pressure ratios of present-day commercial compressors can he raised. The investigation considers certain design limits and the manner in which these limits are affected by the principal design variables of an inlet stage, a typical intermediate stage, and a typical final stage of a multistage axial-flow compressor. Two velocity diagrams were investigated, the wheel plus vortex and the symmetrical at all radii diagrams. The optimum stagewise variations, of axial velocity and relative inlet-air angle are determined. An analysis was made to estimate the possible over-all compressor pressure ratio for several stagewise distributions of these variables. The investigation indicates that for the wheelplus -vortex velocity diagram and procedure followed, the axial velocity should increase stagewise through the compressor and the relative inlet-air angle should be lower in the later stages than in the inlet stage in order to produce the highest over-all total-pressure ratio for a given set of design conditions.
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