A vane-axial flow fan is being designed with the stator blades upstream of the rotor blades (Fig. P14–70). To reduce expenses, both the stator and rotor blades are to be constructed of sheet metal. The stator blade is a simple circular arc with its leading edge aligned axially and its trailing edge at angle β_st = 26.6° from the axis as shown in the sketch. (The subscript notation indicates stator trailing edge.) There are 18 stator blades. At design conditions, the axial flow speed through the blades is 31.4 m/s, and the impeller rotates at 1800 rpm. At a radius of 0.50 m, calculate the leading and trailing edge angles of the rotor blade, and sketch the shape of the blade. How many rotor blades should there be?

FIGURE P14–70

Transcribed Image Text:

Bst Hub and motor ᏯᏛ . ???-- Stator Rotor out