2

Test1

Question 1 (20 points)

A disk with four radial holes rotates at 1,000 rpm clockwise. The air enters the system at 10 g/s.

Each of the axial holes is inclined at βo = 10o (in the direction of the rotation). The inlet radius

(r1) of the radial disk is 20 cm and the outlet radius (r2) is 30 cm. The diameter of the hole is 10

mm. The density of the air is ρ = 1.2 kg/m3.

a) Calculate the incidence angle of the air entering each of the holes. (14 points)

b) Suggest three methods that can be used to force the incidence angle bordering to zero.

(6 points)

3

4

Question 2 (20 points)

A centrifugal pump is used to deliver water from the well to the tank. The vertical distance from

the surface in the well to the centerline of the pump is 10 m, and the vertical distance from the

centerline of the pump to the water surface in the tank is 15 m. The total length of the pipe on the

suction side is 20 m while the total length of the discharge side is 30 m. The required flowrate is

10 gpm. The diameter of suction pipe is 2.54 cm (1 inch) while the diameter of the discharge

pipe is 1.91 cm (0.75 inch). Find the total head of the system.

Figure 1 : Centrifugal pump delivering water from the well to the tank

8 m

5 m

2 m

5

6

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