Numerical simulation of centrifugal and hemodynamically levitated LVAD for performance improvement

Abstract

Left ventricular assist device (LVAD) provides an effective artificial support system to the heart patients. Despite the improved life survival rate, complications like hemolysis, blood trauma, and thrombus formation still limit the performance of the blood pump. The geometrical aspects of blood pumps majorly influence the hemodynamics, therefore these devices must be carefully engineered. In this work, several versions of centrifugal blood pumps are simulated using ANSYS-CFX to propose a best compatible design for LVAD. A hemodynamic levitation approach for the impeller is also suggested to overcome the cost and weight issue associated with the magnetic levitation. The blood flow is modeled by implementing Bird-Carreau model and its turbulence is solved using the SST turbulence model. The influence of the blade profile, blade tip width, blade numbers, and splitter blades on the hemodynamic characteristics through the pump is observed. An optimum design of centrifugal blood pump for the assistance of failed ventricle is proposed that can effectively pump the blood from the left ventricle to the ascending aorta. The proposal can be adopted by LVAD designers to have hemodynamically tuned efficient product. K E Y W O R D Scentrifugal blood pump, damage index estimates, hemolysis, left ventricular assist device, non-Newtonian modeling E2 |

Comparative assessment of different versions of axial and centrifugal LVADs: A review

“…The comparative analysis has been initially made by considering two of the commercially available axial and centrifugal versions of LVADs (HeartMate‐II and HVAD, respectively), 48,49 followed by a comparison of two blood pumps from our recently published studies 50,51 . We have proposed novel designs of axial and centrifugal LVAD pumps in these respective studies.…”

“…The major design details of the pumps are summarized in Table 2. Computational fluid dynamics (CFD) models used for the proposition can be found in these studies 50,51 …”

“…Similar observations were also observed in the H–Q curves of our designs (shown in Figure 3A). 50,51 The H–Q curve for both the pumps has been plotted at several rotational speeds. Again, the hydraulic performance of the axial LVAD is observed to be inferior to the centrifugal version.…”

“…(A) Hydraulic performance and (B) Hydraulic efficiency of centrifugal and axial blood pump at different blood flow rates 50,51 [Color figure can be viewed at wileyonlinelibrary.com]…”

“…Blood damage index at different blood flow rate for axial and centrifugal blood pump 50,51 [Color figure can be viewed at wileyonlinelibrary.com]…”