Predictions of Index of Hemolysis in Shear Blood Flow. Improvement of Accuracy for Prediction by Modifying Turbulence Model for Orifice-pipe Flow.

Abstract

This paper describes the improvement of accuracy for prediction of index of hemolysis in shear blood flow by computational fluid dynamics (CFD) with modified turbulence model, applying to orifice-pipe blood flow, which is simple model of turbulent shear stress induced hemolysis in the high speed rotary blood pump. Using CFD with partially patched modified k-e model (Launder-Kato partially patched model; LK-Zonal), results of the flow field in the orifice-pipe flow are compared with standard low Reynolds number k- model at whole region (STD), and it is found that the shear stress by LK-Zonal model is predicted more precisely than that by STD model near the impinging flow region. As for hemolysis, from the computational data of orifice-pipe flow, the index of hemolysis is estimated in the same way as our previous paper (1) , and it is found that the accuracy for prediction of index of hemolysis is also improved using LK-Zonal model in comparison with STD model, particularly in case of the orifice-pipe flow with large and long contracted part. From these results, the design method using CFD for the rotary blood pumps, that have impinging flow region to the wall, for suppressing the hemolysis can be proposed.