REVIEW OF DESIGN ASSUMPTIONS

This chapter discusses design assumptions. In an axial flow compressor, the axial velocity distribution in the annulus deteriorates to a parabolic form after the first two or three stages. Comparative tests described in the chapter were made on compressors designed for constant axial velocity, the actual axial velocity distribution, and increased total head rise toward the two blade extremities. The highest efficiency was obtained with the first mentioned design. In the second design, the downstream velocity distribution showed deterioration, while some improvement in this regard was achieved with the third type of blading. The efficiency loss in this last case was traced to stator stalling brought about by the large swirl angles encountered at the stator extremities. A theoretical analysis was made of the effect that a radial variation of inlet velocity is likely to have on a rotor designed for constant axial velocity.