Page 77 - Compression Machinery for Oil and Gas

Centrifugal Compressors Chapter 3 67

20,000

NC2 = 15,000 rpm AF2 = 2.05 15,000

Rotordynamic response plot Operating speed 10,000 Rotor speed (rpm)

Second critical Second mode 5000 configurations.

speed

0 unbalance
50 45 40 35 30 25 20 15 10 5 0
mode
Response (microns pk-pk)
20,000 second and

NC1=4060 rpm AF1 =5.84 First mode 18,000 16,000 14,000 first the for

Rotordynamic response plot Operating speed 12,000 10,000 8000 Rotor speed (rpm) examples plot response

First critical speed 6000 4000 2000 amplitude Unbalance

0
50 40 30 20 10 0 3.33
Response (microns pk-pk)
FIG.