Laser doppler anemometer measurements of the flow in the impeller blade channels of a centrifugal blood pump

Hemodynamics in the rotary blood pumps is of great importance for it is highly related to the blood hemolysis and thrombus generation in the blood pumps. In the present study, the flow in the impeller passages of Kyoto-NTN centrifugal blood pump with 16 forward-bending blades was measured using Laser Doppler Anemometer (LDA) ona 1:1 size pump model. The measurement results were compared with those of the numerical simulation study and the measurement results on a 5:1 enlarged pump model. The comparison indicated a reasonable agreement between the results of the present measurement and the numerical simulation. The comparison between the measurement results on the 1:1 and 5:1 enlarged pump models revealed, however, significant differences in the flow patterns. The main cause of the differences between the 1:1 and 5:1 pump model should be due to the incomplete similarity of the later, which has produced 31 % higher dimensionless flow rate than the prototype. Therefore, it is important to require more elaborate arrangements of experimental rig to enhance the flow similarity of the enlarged pump model or, considering the difficulties in achieving the complete similarity of the enlarged pump, the measurements can be suggested to be carried on the pump model that has the same size as the prototype.