Investigation of the flow performance of a nutating blood pump by computational fluid dynamics

In centrifugal blood pumps, blood is moved into a circular path with the help of an impeller. In a nutating pump, the nutating body takes over the role of the impeller. Since the nutating body itself does not rotate, this pump needs no seal, no blood contacting, and no magnetic bearings. To examine the suitability of the nutating pump principle for mechanical heart assist, the flow performance of different nutating pump models was investigated by computational fluid dynamics. The geometrical parameters of the pump were varied and flow-pressure curves were calculated for 12 models at different rotation frequencies. All models showed satisfactory flow-pressure curves. One model was computed minutely at 1 flow configuration to examine shear stresses within the fluid. A flow of 5 L/min and a frequency of 3,300 rotations per min (rpm) resulted in a differential pressure of 85 mm Hg. The maximum shear stress in the fluid at this flow was estimated to be 193 Pa which is considered to be an acceptable value for a blood pump.