Computational fluid dynamics and experimental validation of a microaxial blood pump

Intravascular application of microaxial blood pumps as heart assist devices requires a maximum in size reduction of the pump components. These limitations affect the design process in many ways and restrict the number of applicable experimental procedures, but a detailed knowledge of the hemodynamics of the pump is of great interest for efficiency enhancement and reduction of blood trauma and thrombus formation. Computational fluid dynamics (CFD) offers a convenient approach to this goal. In this study, the inlet, vane, and outlet regions of a microaxial blood pump used as an intraaortic left ventricular assist device are analyzed by CFD and 3-dimensional (3-D) particle tracking velocimetry (PTV). For this purpose, a mock loop is set up that facilitates 3-D flow visualization. Flow in the main part of this testing device is modeled and computed by means of CFD. Pump head/flow (HQ) characteristics, axial pressure distribution, and particle images are then compared with numerical flow data. Results show that the pump performance characteristics, as well as inlet and outlet swirl predicted by the CFD model, are quite accurate compared with measured data. Proper boundary condition definitions and spatial discretization topology requirements for satisfactory results are discussed.