THE EXPERIMENTAL RESEARCH ON AXIS ORBIT OF MIXED-FLOW PUMP

摘要

In order to study the vibration state of the rotor shaft in mixed-flow pump under stable operation, the axis orbit measurement of mixed-flow pump was carried out under design flow condition to obtain the original axis orbit diagram which is then further refined to get the rotative speed frequency(1X frequency) and second harmonic frequency(2X frequency) axis orbit and the time-domain diagram. The results show that when the mixed-flow pump is running at the design condition, some jagged high harmonic signals are included in the axis orbit signals and the original axis orbit has an "8" shaped distribution, which can be caused by factors like the shafting friction and misalignment. In the running process, most part of vibration energy is in 1X frequency which has the maximum amplitude, indicating that the shafting unbalance during operation is caused by hydraulic excitation and other related factors. In the mean time, the axis orbit shape of 2X frequency is like a flat oval with the major axis in the horizontal direction, which indicating that the rotor misalignment also has an influence on the running stability. This study aims at providing practical and theoretical guidance for improving the mixed-flow pump stability and preventing the deterioration of vibration fault.