基于相空间重构离心泵基础振动的研究

确定离心泵基础振动主要影响参数的数量,有利于对基础振动影响参数进行分级并进一步指导低振动离心泵基础的设计。通过隔离电机、管道振动的离心泵试验台架,测试了基础上4个测点的振动位移;运用Tisean3.0通过Fraser互信息算法得出了各测点振动位移时间序列的最佳延迟时间,基于该延迟时间通过伪最近邻点法确定各测点振动时间序列的嵌入维数;最后基于所得最佳延迟时间与嵌入维数对离心泵基础振动时间序列进行了相空间重构,以确定所得延迟时间与嵌入维数的准确性。结果表明,虽然离心泵基础上同一平面内不同测点的振动位移时间序列时域信号不同,但在相空间的重构中具有相同的延迟时间与嵌入维数;不同长度的振动位移序列数据段得到相同的相空间重构参数,表明通过振动位移序列进行相空间重构以确定离心泵基础振动影响因素个数具有稳定性;离心泵基础振动位移时间序列在重构的相空间中具有明显吸引子存在,表明离心泵及其基础所组成系统具有确定的振动规律存在;所建立离心泵试验台基础振动的嵌入维数为4,表明其主要影响参数小于或等于4。

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