Abstract
Although condition monitoring of centrifugal pump bearings to infer faults is common practice, the relationship between a pump’s vibration level and the unsteady flow within has not been extensively researched. The latter, however potentially provides the foundations for further developments in, pump design to increase performance, advanced predictive maintenance programs and, vibration monitoring techniques that can permit inference of pump efficiency states. This paper investigates the correlation between pump vibration and unsteady flow at different motor speeds. A test rig and a numerical CFD model were employed. It was found that flow-induced vibration in general increases with pump speed and was clearly linked to pump efficiency. It therefore seems possible to construct a model to deduce a pump’s efficiency from its pressure and vibration levels, if the efficiency curve is known a priori . However, as the vibration levels are also dependent on the system’s structural natural frequencies and modes, it seems that knowledge of these may also be needed in some instances. The work confirms that utilising a variable speed pump at lower pump speeds allows greater deviations from the design BEP without jeopardising the safety of the pump and should be considered for industrial use.
Highlights
Turbo machinery accounts for nearly 20% of the world’s electrical energy, and up to 50% of energy in industrial plant operations [1]
This paper aims to identify, by means of experimentation and numerical methods, how centrifugal pump vibration and unsteady flow are related at different motor speeds
It seems that the hydraulic induced vibration generally increases with increasing motor speed which makes physical sense as more energy is fed into the system, and a greater amount of pressure fluctuations can induce vibration responses
Summary
Turbo machinery accounts for nearly 20% of the world’s electrical energy, and up to 50% of energy in industrial plant operations [1]. The potential for cost savings provides technological companies with motivation to place considerable time and effort on pump design research. Vibration is the leading cause of pump component failure and reduced pump performance. Pressure fluctuations interact with the volute casing and tongue region within the pump and give rise to unsteady forces, which, in turn, produce hydraulic vibration and noise. According to van Esch [2], pump design can only make further progress if effort is made to understand the internal flow. Further research is required to better understand the relationship between vibration and unsteady flow inside centrifugal pumps for different operating conditions
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