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

Table 7

First natural frequencies of the various length rotors with the prestresses.

D (mm)	900	1200	1500	1800	2000	2400	2700	3000
First natural frequency (with prestress) f (Hz)	57.444	34.879	23.331	17.115	13.975	9.905	7.989	6.578
First natural frequency (without prestress) f (Hz)	54.513	32.717	22.024	16.143	13.220	9.320	7.549	6.218