Transfusion technology
A pipette is a small tube that aspirates liquids. It works by creating a partial vacuum above the liquid-holding chamber and selectively releasing this vacuum to draw up and dispense.
In a blood mixing device a blood concentrate is diluted with plasma. The concentration of red blood cells are reduced to a well-tolerated level for the human organism. A simple confluencing of both fluids does not lead to a homogenous mixture because the viscosity of the concentrated RBCs is much higher than that of plasma.
Aim – The optimized blood mixing device provides a homogenous mixing with minimized damage potential for blood cells. Simulation: The mixing behaviour can be analyzed with a multiphase system flow simulation. The viscosity of the suspension is changed with the proportion of the red blood cells. Hemolysis models allow to determine the risk of blood damage by high shear rates in the cross-section reductions.
Method – Models for multiphase flow allow the calculation of problems with free surfaces such as in pipettes. Beside the influence of gravity, also fluidspecific conditions such as surface tension and wetting of solid surfaces are considered.
Results – Based on the the phase distribution, velocity and pressure fields, the pipette design is optimised regarding its aspiration behaviour, the prevention of air inclusions and the damage of sensitive media.
