Numerical Analysis of the FDA Centrifugal Blood Pump

Ventricular Assist Devices (VADs) are commonly implanted to assist patients suffering fromheart diseases. They provide long- and short-term support for the human heart and help patientsto recover from heart attacks and from congestive heart failure. It is essential to design bloodsensitiveVADs to minimise the risk of hemolysis and thrombosis. The blood pump, however,must operate at a wide range of flow rates and pressure heads which makes a low-risk design achallenging task. In this study the flow in a centrifugal blood pump, provided by the U.S. Foodand Drug Administration (FDA), is investigated by means of numerical simulations on highperformance computers. The simulations are carried out for different operation REYNOLDSnumbers. A total of 15 pump revolutions is performed to obtain quasi-steady results. The pressuredrop across the pump is considered to study convergence of the solution and to characterisethe energy loss of the device. Investigations of the velocity field show that there exist high velocitiesand strong velocity gradients and shear layers in the outflow region potentially leadingto hemolysis. Investigations of the wall-shear stress reveal the existence of thin boundary layersat the blade tips. Finally, the motor torque is investigated to identify the force acting onthe blades. All the findings show that there is a strong need to develop more blood-sensitivedesigns to reduce the risk of hemolysis and thrombosis