Computational fluid dynamics analysis of a centrifugal blood pump with washout hole diameter variations.

The centrifugal blood pump is used widely for medical treatment in end-stage Heart failure patients. However, the flow conditions inside the centrifugal blood pump may cause blood traumas, i.e., thrombosis and hemolysis. Computer fluid dynamics (CFD) has been applied to blood pump designs and evaluations to describe if the new design of the pump components may cause these undesirable conditions. In this study, an investigation of a centrifugal blood pump was carried out through CFD simulations. The study of such computer simulations focuses on the generated pressure head, types of flow pattern, velocity, and wall shear stress of the blood pump. Four impeller designs with different washout hole diameters of 5 mm, 7 mm, 9 mm, and 10.13 mm were studied during the operating condition of 2500 RPM rotating speed and a 5 L/min flow rate. The result showed that, at the desired condition, the variation of the washout hole diameter does not significantly affect the pressure head. Meanwhile, the Reynold number (Re) can distinguish the type of flow that occurs inside the washout hole. The high Re can be observed in the impellers with 9 mm and 10.13 mm washout holes stating the occurrence of turbulence flow which is one of the causes of hemolysis.