Research on base vibration of centrifugal pump by phase space reconstruction

Abstract: The identification of the number of the parameters that mainly influence the vibration of a centrifugal pump base is good for the classification of all the parameters concerned with the centrifugal pump system into different levels and guiding the design of a low-vibration centrifugal pump base. A centrifugal pump test bench which isolates vibration from motor for driving and pipeline for water transferring, as well as background vibration, was built by installing a contactless electromagnetic clutch between the motor and the centrifugal pump, and by mounting corrugated pipe between the centrifugal pump and the pipeline. The vibration displacements of four testing points which are on the same centrifugal pump base plane that is vertical to the symmetry plane of volute were gained by a LMS data acquisition system and four eddy current displacement sensors. Mutual information of a time series about each of the four vibration displacements were computed by the Tisean 3.0 toolbox with a Fraser mutual information algorithm when the data length of the time series segments were 10 240, 20 480, and 30 720 respectively. Then the optimal time delay corresponded to the first minimal of mutual information. Based on these optimal time delays, the embedding dimensions of the four time series were also determined by Tisean 3.0 with a False Nearest Neighbors algorithm when the data lengths of each segment of the four time series were 10 240, 20 480, and 30 720 respectively. Finally,, the phase space reconstruction of the four time series about centrifugal pump base vibrations are carried out respectively, which was based on their optimal time delays and embedding dimensions, so as to validate the accuracy of the time delays and embedding dimensions. The results indicated that the time area vibration signals of different measuring points on the same plane of centrifugal pump base were certainly not the same, but they shared the same optimal time delay and the same embedding dimensions for phase space reconstruction. The reconstruction of phase space to confirm the effect factors of the base vibration by a displacement series has stability, because the same optimal time delay and embedding dimensions can be gained by vibration displacement series segments with different data lengths. Attractors, which show that the system made up by centrifugal and its base, owns an established vibration regulation, definitely exists in the reconstructed phase spaces of a vibration displacement of points on a centrifugal pump base. The main parameters which influenced vibration of the built centrifugal pump test bench were not more than 4, because the embedding dimensions of a vibration displacement time series are 4