Experimental Investigation of the Effect of Radial Gap and Impeller Blade Exit on Flow-Induced Vibration at the Blade-Passing Frequency in a Centrifugal Pump

Table 3

Effect of gap on pump performance, 𝑄=𝑄_𝑛.

Gap (mm)	Impeller-I		Impeller-II
	% change in head	% change in efficiency	% change in head	% change in efficiency
2	−1.30	−1.88	0.74	0.74
3	0.55	0.11	−0.42	0.27
3.6	—	—	—	—
4.85	−0.15	−1.36	−2.92	−0.88
6	−0.93	−0.50	−4.99	−2.40
7	−2.41	−1.43	−5.51	−1.53