Hemolysis Related to Turbulent Eddy Size Distributions Using Comparisons of Experiments to Computations

Turbulent blood flow in medical devices contributes to blood trauma, yet the exact mechanism(s) have not been fully elucidated. Local turbulent stresses, viscous stresses, and the rate of dissipation of the turbulent kinetic energy have been proffered as hypotheses to describe and predict blood damage. In this work, simulations of experiments in a Couette flow viscometer and a capillary tube were used to examine extensive properties of the turbulent flow field and to investigate contributing factors for red blood cell hemoglobin release in turbulence by eddy analysis. It was found that hemolysis occurred when dissipative eddies were comparable in size to the red blood cells. The Kolmogorov length scale was used to quantify the size of smaller turbulent eddies, indicating correspondence of hemolysis with number and surface area of eddies smaller than about 10 μm when a k-ε turbulence model is adopted.