Spatial and temporal features of cavitation in micropump by dynamic mode decomposing

Abstract

This study investigates the spatial and temporal features of micropump cavitation. The numerical model is based on the k-Epsilon turbulence model and the Zwart cavitation model. Cases with different rotation speeds and flow volumes are carried out experimentally to validate the numerical model by changing rotation speed and flow rate separately. The periodic to chaos cavitation is observed by varying the cavitation number. Spatial modes of cavitation on the blade are identified by the dynamic mode decomposing. The frequencies of those modes are also obtained. The most energetic modes are presented and discussed. Cavitation of micropump on the suction side of the blade experiences growing, breaking, and shedding. With the decrease of cavitation number, the cavitation occurs at the leading-edge part, the middle part, and the entire blades. The leakage of cavitation can result in the interaction between cavitation between neighboring gaps of blades and the symmetrical distribution. The results also show that with the increase of cavitation number, there exists a downshift of frequency, and the bump point of the blade can influence the cavitation significantly.