An analytical study was made of four combinations of subsonic and supersonic flow in the rotor- and stator-blade passages of axial-flow compressors. The theoretical total-pressure ratio of each of these types of compressor, when only normal-shock losses are considered, is given as a function of the rotational speed and the turning angle in the rotor passage.nCompressor I with a rotor-contained normal shock and subsonic velocity at the stator entrance offered a total-pressure ratio of about 3.5 per stage and for no change in outer shroud radius was limited by the stator-entrance angles and stator-entrance Mach numbers to a maximum total-pressure ratio of about 4.6 per stage.nCompressor II had a rotor-contained normal shock but permitted supersonic velocities at the stator entrance. Total-pressure ratios above 6.0 per stage were theoretically possible, but problems such as stabilizing normal shocks in both the rotor and the stator, large turning in the rotor passage, and utilizing the high stator-entrance angles require further investigation.nCompressor III utilized supersonic flow throughout the rotor and recovered the pressure in supersonic stators having a contained normal shook. Total-pressure ratios above 5.0 were possible in a single stage, but normal shock losses were greater than for the other types at comparable pressure ratios above 3.0. Because the shock was removed to the stator, however, devices for approaching isentropic deceleration through sonic velocity may be more easily applied.
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