Experimental Research of Journal Orbit for Water-Lubricated Bearing

Abstract

To study the transient dynamic characteristics of water-lubricated bearing-rotor system in seawater desalination high pressure pump, the water-lubricated bearing test device was designed and built based on the prototype of high pressure pump with 4-stage rotors. The test was conducted to study the journal orbit and circumferential pressure distribution of journal bearing. The result shows that, in startup stage, the journal whirled with little amplitude in low revolution speed, and as the revolution speed increased, the journal began to move irregularly. The hydrodynamic lubrication formed basically when close to the rated revolution speed, and there is stable whirling center and amplitude of the journal orbit. The circumferential pressure distribution of journal bearing changed severely and kept consistent with the change of journal orbit; when the revolution speed reached the rated speed, the pressure distribution is stable. We changed the radius clearance, the aspect ratio, and the rotating speed to analyze the influence on the bearing-rotor system at steady speed. In conclusion, the journal orbit and circumferential pressure of journal bearing are very stable when the clearance radius is 0.05 mm, the aspect ratio is 1, and the revolution speed is 3000 r/min.

A New Method to Calculate Water Film Stiffness and Damping for Water Lubricated Bearing with Multiple Axial Grooves

“…The projection of bearing load to r-φ co-ordinate system is then (18) In Eqs. (22), (23), the function K (η) is one of the function K L (η) , K E (η) or K P (η) depending on which one is chosen. The same applied to function C(η) .…”

“…(24) and (25) into Eqs. (22) and (23), their matrix form can be expressed as The coefficients of stiffness and damping for the pad with index "i" are: (25)…”

“…In spite of this paper doesn't include the effect of elastic deformation of bearing surface in terms of elastohydrodynamic lubrication, the results are valid approximately for polymer bearings with higher hardness and lower pressure that most pump and turbine guide bearings are the case. The result is not suitable to water lubricated bearings with rubber staves that needs special treatment either through experiment [20][21][22][23][24][25][26][27][28][29] or numerical analysis. Experimental study on bearings with multiple axial grooves demonstrates that a relatively rigid surface of bearing pad more easily forms hydrodynamic pressure than soft surface [22].…”

A dynamic response test rig of a full-scale rotor–journal bearing system

“…Ye et al. 6 designed a test device of a water-lubricated bearing in a seawater desalination pump. Sun et al.…”

“…The second strategy to build the test rig is based on a real rotating machinery model. Ye et al 6 designed a test device of a water-lubricated bearing in a seawater desalination pump. Sun et al 7 investigated journal misalignment based on a test rig that consisted of two cylindrical journal bearings.…”