Question

Problem #1: A centrifugal compressor has a mass flow rate of 1.6 kg/s while rotating at 11,000 rpm. The impellor is a radial impellor meaning that the blades are strictly radial at exit (β2' = 0). The radius of the radial impeller at exit is 0.3 m with a blade width 0.01 m. Assume that the entrance flow is axial. For this compressor, the compressor efficiency is 83% and the slip coefficient is 0.9. (a) Clearly sketch the velocity triangles at the exit of the impellor. Include the flow slip and mark all the angles and velocities.

Answer 1

a) The slip coefficient is 0.9

b) Blade tip speed is 345.57 m/s

c) Stagnation temperature exiting the impellor is 416.84 k

d) Exit flow velocity is 84.88 m/s

e) Exit flow angle is 76.2°

f) Exit static temperature is 353.84 k

g) Impellor exit Mach number is 0.943

Step-by-step explanation:

Flow at entry is axial α₁ = 0

Tagential velocity at entry
`V_(w1)`= 0

Blade at exit is radial β₂ = 0

μ₂ =
`V_(w2)`