Numerical Study of a Bio‐Centrifugal Blood Pump With Straight Impeller Blade Profiles

Abstract

Computational fluid dynamic simulations of the flow in the Kyoto-NTN (Kyoto University, Kyoto, Japan) magnetically suspended centrifugal blood pump with a 16-straight-bladed impeller were performed in the present study. The flow in the pump was assumed as unsteady and turbulent, and blood was treated as a Newtonian fluid. At the impeller rotating speed of 2000 rpm and flow rate of 5 L/min, the pump produces a pressure head of 113.5 mm Hg according to the simulation. It was found that the double volute of the pump has caused symmetrical pressure distribution in the volute passages and subsequently caused symmetrical flow patterns in the blade channels. Due to the tangentially increasing pressure in the volute passages, the flow through the blade channels initially increases at the low-pressure region and then decreases due to the increased pressure. The reverse flow and vortices have been identified in the impeller blade channels. The high shear stress of the flow in the pump mainly occurred at the inlet and outlet of the blade channels, the beginning of the volute passages and the regions around the tips of the cutwater and splitter plate. Higher shear stress is obtained when the tips of the cutwater and splitter plate are located at the impeller blade trailing edges than when they are located at the middle of the impeller blade channel. It was found that the blood damage index assessed based on the blood corpuscle path tracing of the present pump was about 0.94%, which has the same order of magnitude as those of the clinical centrifugal pumps reported in the literature.

Acquired von Willebrand syndrome in patients with extracorporeal life support (ECLS)

“…The ECLS devices analyzed in this study are centrifugal or diagonal pumps with rotational speeds of several thousand rpm. All pump types used for VADs are believed to exert nonphysiologically high shear stress on blood [26][27][28][29][30][31]. In centrifugal and diagonal pumps, shear rates depend on design [28,29] and on pump speed [31].…”

Numerical Simulation of LVAD Inflow Cannulas with Different Tip

“…The estimation value of blood damage was between 5 × 10 -5 % to 20 × 10 -5 %. The acceptable estimation value of blood damage for LVAD was 10 -3 % [27,28]. So the blood damage in inflow cannula was negligible.…”

Evaluation of the Impeller Shroud Performance of an Axial Flow Ventricular Assist Device Using Computational Fluid Dynamics

“…Hundreds of particles are sampled in both models, and the mean blood damage indices of both models are both around 1%. Although the formula proposed by Giersiepen et al (23) overestimates the hemolysis obtained in the in vitro hemolysis test (4,14,25), a relative good correlation between the estimated and measured hemolysis can be obtained (16,(26)(27)(28). Because a hemolysis test was not conducted in this study, the experimental results of an axial flow blood pump investigated by Yano et al (16) was used for comparison.…”