Proposal of hemodynamically improved design of an axial flow blood pump for LVAD.

Left ventricular assist devices (LVAD) emerges as an effective clinical device providing life-saving support to heart patients. The design of blood pump of an LVAD involves incredible accuracy and thorough understanding of hemodynamics to mimic the functionality of a healthy ventricle. This work studies hemodynamics around an LVAD and proposes an improved model of axial blood pump for cardiac circulation without any hemolysis complications through numerical investigations. A three-dimensional study on different versions of the impeller with three curved blades (pump I) and spiral blade (pump II) is carried out by utilizing computational fluid dynamics software ANSYS-CFX at a range of rotational speeds and flow rates. The non-Newtonian blood flow through pump is modeled by using Bird-Carreau model. To capture the change in the flow field near the rotating blade, a transient blade row model was employed. The proposal of spiral blade impeller was found to be more compatible as per the hemolytic performance. It considerably reduces the blood damage to two times lesser value than that by pump I and also improves the quality blood flow field. The spiral blade provides a guiding path to the blood particle and avoids mixing of different bloodstreams, thus reducing the eddy losses. Graphical abstract The graphical abstract shows the performance enhancement of the axial blood pump. The model proposed by Peng et al. (Comput Methods Biomech Biomed Engin 17(7):723-727, 2014) has been upgraded to two new versions by redesigning its impeller. Proposed design (pump II) shows improvement in pressure distribution (a) and reduction in hemolysis (in the case of pump II) index (b).