Page 207 - Fluid Mechanics and Thermodynamics of Turbomachinery

188 Fluid Mechanics, Thermodynamics of Turbomachinery

FIG. 6.10. (a) Pressure variation in the neighbourhood of a rotating blade row. (b) Axial
velocity at the hub in the neighbourhood of a rotating blade row (adapted from
Hawthorne and Horlock 1962).

geometry, a blade row of reduced width may be considered to affect the flow in
exactly the same way as the original row. In the limit as the axial width vanishes, the
blade row becomes, conceptually, a plane discontinuity of tangential velocity the
actuator disc. Note that while the tangential velocity undergoes an abrupt change in
direction, the axial and radial velocities are continuous across the disc.