Wet Modal Analyses of Various Length Coaxial Sump Pump Rotors with Acoustic-Solid Coupling

Table 8

Predicted first natural frequencies and measured [22] and predicted critical speeds for various rotor lengths from the wet mode analysis.

D (mm)	Predicted first natural frequency f (Hz)	Predicted first critical speed n (RPM)	Measured first critical speed [22], n (RPM)
900	48.265	2878	3467
1200	29.194	1741	2107
1500	19.482	1158	1429
1800	14.326	850	1038
2000	11.753	700	862
2400	8.340	498	623
2700	6.711	399	505
3000	5.531	330	417