A new trial towards the development of centrifugal blood pump for the children with cardiac failure: Numerical design and evaluation of a prototype

For the purpose of supporting the in-vitro circulation of the children with cardiac failure, a centrifugal blood pump is under development in our hospital, currently. We design a suspended impeller with a single supporting point bearing to provide a blood flow. Towards the end of efficient design, the techniques of computer-aided design (CAD) and computational fluid dynamics (CFD) are employed for the development and quantitative evaluation of the fluid dynamic performance. In this study, we report the process of the design and CFD estimation of the dynamic characteristics of a prototype. The three-dimensional flow features inside of the pump were predicted. An unobstructed blood flow path without secondary flow and stagnated flow regions was achieved. The pressure-flow curves, hydraulic efficiencies and wall shear stress (WSS) of the blades were calculated. The results indicated the design of the impeller was good enough to generate a relatively efficient flow patterns in the blade passage to reduce the flow separation and formation of vortices which are believed to increase the degree of hemolysis and thrombosis. In addition, the flow through the hydrodynamic bearing at the center of the impeller and the effects of bearing clearance on shear stress were also investigated for the further optimization of the pump design and the improvement of the hemolytic performance. This implied the analysis of CFD simulation were the efficient tool in the evaluation of the blood pump design.