Centrifugal Pumps Design and Application 2nd ed - Val S. Lobanoff, Robert R. Ross (Butterworth-Heinemann, 1992)
Share Embed Flag
Download ePaper

Centrifugal Pumps Design and Application 2nd ed - Val S. Lobanoff, Robert R. Ross (Butterworth-Heinemann, 1992)

ariejulianto
from ariejulianto More from this publisher
24.01.2016 Views

Vibration and Noise in Pumps 481 Figure 18-36. Three-stage pump—unbalanced response—with seals. Pulsation Induced Vibrations [14]. A four-stage centrifugal pump suffered repeated failures of the splitter between pump stages. A detailed field study revealed the cause of the problems to be an acoustic resonance of the long cross-over that connected the second-stage discharge with the third-stage suction (Figure 18-38). The resonant frequency was a halfwave acoustic resonance.

482 Centrifugal Pumps: Design and Application Figure 1S-37. Three-stage pump—comparison of measured and calculated response. where: c = acoustic velocity, ft/sec L = length, ft The speed of sound in water is a function of the temperature, and at 310°F was calculated to be 4,770 ft/sec. The length of the cross-over was 5.75 ft. The acoustic natural frequency was The acoustic resonant frequency was excited by the vane passing frequency (seven times running speed). Coincidence occurred at (415) (60)/ 7 = 3,560 rpm. Dynamic pressure measurements in the center of the cross-over showed pulsation amplitudes of 100 psi peak-to-peak. The pulsations at the suction and discharge flanges were less than 10 psi peak-to-peak, which agreed with the mode shape of the half-wave acoustic resonance. There were two possible changes that could eliminate the coincidence of vane passing frequency with the resonant frequency and reduce the

Vibration <strong>and</strong> Noise in <strong>Pumps</strong> 481<br />

Figure 18-36. Three-stage pump—unbalanc<strong>ed</strong> response—with seals.<br />

Pulsation Induc<strong>ed</strong> Vibrations [14]. A four-stage centrifugal pump suffer<strong>ed</strong><br />

repeat<strong>ed</strong> failures of the splitter between pump stages. A detail<strong>ed</strong><br />

field study reveal<strong>ed</strong> the cause of the problems to be an acoustic resonance<br />

of the long cross-over that connect<strong>ed</strong> the second-stage discharge with the<br />

third-stage suction (Figure 18-38). The resonant frequency was a halfwave<br />

acoustic resonance.

logo

products

Resources

Company

Terms of service
Privacy policy
Cookie policy
Cookie settings
Imprint
Change language
Made with love in Switzerland
© 2024 Yumpu.com all rights reserved

Hooray! Your file is uploaded and ready to be published.

Saved successfully!

Ooh no, something went wrong!