PIV experimental study on the flow field characteristics of axial flow blood pump under three operating conditions

In order to investigate the internal flow field of an axial blood pump, two‐dimensional (2D) particle image velocimetry (PIV) was applied to test the blood pump under three different conditions. Acquiring the images of inlet, front guide vane, impeller, back guide vane and outlet area, the distribution of internal flow field was then analysed. The rotation speed of the blood pump was set to 6000, 7000 and 8000 r/min, respectively. The results show that the flow field of blood pump is stable relatively at the inlet area. Some vortices and reflux existed due to the block of guide vane in the import and impeller area. With the increase of rotating speed, the overall disturbance degree of flow field increases. Under the condition of low rotation speed, the flow field acceleration is insufficient. Under the medium rotation speed condition, the flow field is stable and the velocity distribution is even. Under the condition of high rotating speed, the number of vortices in the flow field increased significantly, the flow separation phenomenon at the impeller was obvious and more unstable flow appeared at the back guide vanes and outlet area.