Theory versus experiment for leakage and rotordynamic coefficients of circumferentially-grooved liquid annular seals with L/D of 0.45
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This paper presents an experimental study of circumferentially-grooved annular seals. The influence of pressure drop, running speed, and static eccentricity on rotordynamic coefficients has been investigated. Rotordynamic coefficients are accurately predicted by the theory, except for the cross-coupled stiffness term, which is under predicted by about 40%. Grooved seals leak less at lower speeds than smooth seals. Direct and cross-coupled stiffness as well as direct damping are greatly reduced. Leakage flowrate and rotordynamic coefficients are insensitive to static eccentricity ratios up to 0.5. The whirl. frequency ratio of grooved seals is substantially smaller than smooth seals, suggesting a stability advantage. However, net damping was much lower for grooved seals than smooth seals, which is consistent with the customary experience that smooth seals generally enhance pump rotordynamic response and stability in comparison to grooved seals.
author list (cited authors)
Marquette, O. R., Childs, D. W., & Phillips, S. G.