E7.13 An axial flow turbine blade 10.2cm in height is attached to a 50.8cm radius turbine wheel as shown in Figure E7.19. The blade is designed to receive air from a stator that has an outlet angle 4-20. When the linear speed of rotation at the root of the blade (that is, at the point where the blade is attached to the wheel) is 213m/s the angle of incidence of the chord line of the blade there is i=3. The absolute velocity from the stator outlet is constant at c4-549m/s. Consulting the sketch below and assuming incompressible flow: (a) Find the stagger angle y of the blade chord at the root (b) If the blade is untwisted throughout its height find the angle of incidence at the tip of the blade under the given conditions (c) Find the work performed per unit mass of fluid processed if the rotor blade provides an exit absolute velocity that is purely axial. blade tip blade root 10.2cm W4 W4 -i+i stator 50.8cm chord line C4 rotor Definition of incidence and stagger angles 2001 stage